Patent Publication Number: US-2023149721-A1

Title: Implantable pacemaker with automatic implant detection and system integrity determination

Description:
This application claims the benefit of U.S. Provisional patent application Ser. No. 63/264,252 filed on Nov. 18, 2021, the entire contents of which are incorporated herein by reference. 
    
    
     BACKGROUND 
     Implantable medical devices (IMDs), such as cardiac pacemakers, are often configured to be connected to leads. The leads include electrical conductors that extend through a lead body from a connector assembly provided at a proximal lead end to one or more electrodes located at the distal lead end or elsewhere along the length of the lead body. The conductors connect stimulation and/or sensing circuitry within the IMD housing to respective electrodes or other sensors on the lead. 
     Therapeutic electrical signals provided by the leads connected to the IMD may include pulses or shocks for pacing, cardioversion, or defibrillation. In some cases, an IMD senses intrinsic depolarizations of the heart, and controls delivery of therapeutic signals to the heart based on the sensed depolarizations. An IMD may also be used to conduct temporary cardiac pacing on a temporary basis (for example, up to about 90 days). Temporary pacing may be prescribed to patients who may have temporary conduction disturbances, such as following the end of an operative procedure, or as a bridge between permanent implants in cases of device or system infection. In some examples, conduction disturbances treatable using a temporary IMD may be the result of transcatheter aortic valve replacement (TAVR), or may be caused by alcohol septal ablation or Lyme carditis. 
     The implantation of an IMD, such as a temporary or permanent pacemaker, has typically required one or more custom support instruments such as, for example, a device programmer, to perform a number of confirmation checks on the IMD at the time of implant. These confirmation checks help to ensure that the IMD and leads are properly implanted and operational post implant procedure, and can be important to ensure that the system provides prescribed therapy to a patient beginning at the time of implant. 
     SUMMARY 
     When a temporary or permanent IMD is implanted, in some cases the practitioner performing the implant procedure lacks experience, or performs the implant procedure infrequently. In other cases, the implant procedure may be performed at a location or under emergency conditions where the practitioner performing the implant procedure may not have access to custom device programming instruments. In such situations the practitioner may desire rapid feedback on whether the implantation procedure was performed successfully. In some examples, the most readily available feedback on proper implantation is a surface electrocardiogram (ECG), which, in the absence of a sophisticated external programmer, can be monitored by the clinician performing the implant procedure. 
     In general, the present disclosure is directed to techniques in which, after leads are attached to the IMD, the IMD triggers performance of diagnostic self-tests and provides rapid feedback to the practitioner to support the implant procedure. In some examples, following lead connection, the temporary or permanent IMD performs at least some of the following diagnostic tests: detection of qualification of connection to a pacing electrode(s), determination that the IMD is able to adequately sense intrinsic cardiac activity of the patient, determination that pacing operations generated by a signal generator or an implantable pulse generator (IPG) in the IMD are acceptable for implant, e.g., that pacing pulses capture the heart, and detection of proper lead fixation via assessment of current of injury (COI) parameters. 
     In some examples, the IMD performs periodic lead impedance monitoring to detect connection to electrodes, integrity of the lead, and/or connection of the electrodes to the heart. In some examples, detection of lead impedance in a valid range triggers other diagnostic tests such as monitoring a patient electrogram (EGM) to allow measurement of amplitudes alone or in combination with calculation of COI parameters. If the EGM amplitude and COI parameters are satisfied, the IMD may perform other test or measurements. In some examples, the IMD may lower a pacing rate, if necessary, to allow intrinsic conduction to determine EGM amplitudes, e.g., to confirm R-wave detection. In some examples, after EGM sensing has been confirmed, or it is determined that intrinsic conduction does not occur even when the pacing rate is lowered to threshold, e.g., indicating pacer dependency, IMD may perform capture tests to determine the pacing capture threshold (PCT), e.g., to determine whether the PCT is within an acceptable range for operation of the IMD. 
     In some examples, if the IMD does not itself make capture determinations, a clinician may observe the rhythm of the patient on an ECG monitor, and determine adequate R-wave sensing and device capture based on these observations. In some examples, the IMD confirms device capture by pacing the heart and detecting a signal confirming device capture. In some examples, IMD repeats the qualification test cycle for a predetermined period of time (for example, about 30 minutes) to provide continued monitoring of pacing and sensing effectiveness until (and in some cases after) the implantation procedure is complete (e.g., until or after skin closure). The IMD may provide confirmation of pacing and sensing effectiveness to a clinician via a confirmation signal, as described herein. 
     In some examples, the IMD performs these self-test algorithms without any external instrument or programming device, other than an optional ECG monitor that can display heart rate with some accuracy, and as such the method of the present disclosure can simplify the IMD implantation procedure and evaluation of device capture. In this manner, the techniques of this disclosure may improve the performance of the IMD during an implantation procedure or other performance evaluation, particularly in cases where custom support instruments may not be available. 
     In one aspect, the present disclosure is directed to an implantable medical device (IMD) configured to be coupled to at least one implantable medical lead, wherein the IMD comprises: sensing circuitry configured to sense an electrogram (EMG) signal of a patient via at least one electrode of the implantable medical lead; impedance measurement circuitry to measure impedance via the implantable medical lead; and a processor. The processor is configured, in response to coupling of the IMD to the at least one implantable medical lead, to initiate a device test sequence comprising a plurality of qualification tests over an evaluation period in which the processor: (1) controls the impedance measurement circuitry to measure an impedance for at least one electrical path that includes the at least one electrode to determine a connection status of the IMD to the at least one electrode; and (2) compares EGM (electrogram) amplitudes of the patient over an EGM test period against a predetermined threshold. 
     In another aspect, the present disclosure is directed to a method comprising detecting, by an implantable medical device (IMD), attachment to the IMD of at least one implantable medical lead, wherein the at least one implantable medical lead comprises at least one electrode, and triggering by the IMD, based on the detecting of the attachment to the IMD of the at least one medical lead, a device test sequence in which the IMD performs the following qualification tests over an evaluation period: (1) detecting an impedance for at least one electrical path that includes the at least one electrode to determine a connection status of the IMD to the at least one electrode; and (2) comparing EGM (electrogram) amplitudes of the patient over an EGM test period against a predetermined threshold. 
     In another aspect, the present disclosure is directed to a computer-readable medium comprising instructions that cause a processor to: following connection of the implantable medical device (IMD) to at least one lead, the lead including an electrode, controlling the IMD to automatically initiate, without input from an external programming device, a device test sequence in which the IMD performs the following qualification tests over an evaluation period: (1) detecting an impedance for at least one electrical path that includes the at least one electrode to determine a connection status of the IMD to the at least one electrode; and (2) comparing, over an EGM test period, cardiac sensed event amplitudes in an electrogram of the patient over an EGM test period against a predetermined threshold. 
     The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages of the disclosure will be apparent from the description and drawings, and from the claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a conceptual drawing illustrating an example system that includes a temporary or permanent implantable medical device (IMD) coupled to implantable medical leads. 
         FIG.  2    is a functional block diagram illustrating an example configuration of the IMD of  FIG.  1   . 
         FIGS.  3 - 6  and  7 A- 7 C  are flow diagrams of example operations according device test sequences that may be performed, at least in part, by an IMD according to the present disclosure. 
         FIG.  8    is a conceptual diagram illustrating a configuration of another example IMD. 
     
    
    
     Like symbols in the drawings indicate like elements. 
     DETAILED DESCRIPTION 
     In general, in this application an IMD is configured to perform a number of diagnostic tests following initial implantation in an automated fashion. In some examples, these diagnostic tests are performed by the IMD without input from an external programmer or other monitoring device. In some examples, the diagnostic tests performed by the IMD include periodic lead impedance monitoring to detect connection to electrodes, which in some examples is triggered by attachment of leads to the IMD. In some examples, detection of lead impedance in a valid range triggers measurement by the IMD of EGM amplitudes, and may include lowering the pacing rate generated by the IMD, if necessary, to uncover intrinsic signals, e.g., R-waves, in the EGM signals. In some examples, detection of lead impedance in a valid range can trigger measurement by the IMD of COI parameters. In some examples, after sensing of R-waves or another indication of adequate sensed EGM amplitudes, or it is determined that the patient does not have intrinsic conduction detectable at a lower escape interval, the IMD performs testing of pacing capture. 
     In some examples, the IMD presents a confirmation signal to the user based on successful completion of the test sequence, e.g., after determining an adequate pacing capture threshold. In some examples, the confirmation is observable on an ECG by a clinician as a fixed pacing rate, or pacing pattern such as, for example, alternating rates and/or alternating pacing outputs, over a predetermined time period. The confirmation cycle may repeat for a period of time (for example, about 30 minutes) to provide continued monitoring of pacing and sensing effectiveness as (and in some cases after) the implantation procedure is completed. The IMD may provide confirmation of pacing and sensing effectiveness to a clinician via a confirmation signal, as described herein. 
       FIG.  1    is a conceptual diagram illustrating a portion of an example implantable medical device system  100  in accordance with one or more aspects of this disclosure. In the example of  FIG.  1   , implantable medical device system  100  includes one or more implantable medical leads  112  and an implantable medical device (IMD)  126 . Implantable medical lead  112  includes an elongated lead body  118  with a distal portion  120 . Distal portion  120  of implantable medical lead  112  is positioned at a target site  114  within a heart  122  of a patient  116 . Distal portion  120  may include one or more electrodes. Target site  114  may be located at a wall of a ventricle of heart  122 . In various examples, the lead  112  may be a unipolar, a bipolar, or a multipolar lead. 
     A clinician may maneuver distal portion  120  through the vasculature of patient  116  to position distal portion  120  at or near target site  114 . For example, the clinician may guide distal portion  120  through the superior vena cava (SVC) to target site  114  on or in a ventricular wall of heart  122 , e.g., at the apex of the right ventricle as illustrated in  FIG.  1   . In some examples, other pathways or techniques may be used to guide distal portion  120  into other target implant sites within the body of patient  116 . Other target implant sites may include the ventricular septum, e.g., for delivery of conduction system pacing via one or more of the His bundle, the right bundle branch, or the left bundle branch. Implantable medical device system  100  may include a delivery catheter and/or outer member (not shown), and implantable medical lead  112  may be guided and/or maneuvered within a lumen of the delivery catheter in order to approach target site  114 . 
     Implantable medical lead  112  may include electrodes  124 A and  124 B configured to be positioned on, within, or near cardiac tissue at or near target site  114 , and a housing  127  of IMD  126  may include a housing electrode  124 C. Electrodes  124 A- 124 C may collectively be referred to “electrodes  124 ”, and the number and locations of electrodes  124  shown in  FIG.  1    are merely examples. In some examples, electrodes  124  are configured to function as electrodes to, for example, sense EGM signals of heart  122  and provide pacing to heart  122 . 
     Electrodes  124  may be electrically connected to conductors (not shown) extending through lead body  118 . In some examples, the conductors are electrically connected to therapy delivery circuitry of IMD  126 , with the therapy delivery circuitry configured to provide electrical signals through the conductor to electrodes  124 . Electrodes  124  may conduct the electrical signals to the target tissue of heart  122 , causing the cardiac muscle, e.g., of the ventricles, to depolarize and, in turn, contract at a regular interval. Electrodes  124  may also be connected to sensing circuitry of IMD  126  via the conductors, and the sensing circuitry may sense activity of heart  122  via electrodes  124 . Electrodes  124  may have various shapes such as tines, helices, screws, rings, and so on. Again, although a bipolar configuration of lead  112  including two electrodes  124  is illustrated in  FIG.  1   , in other examples IMD  126  may be coupled to leads including different numbers of electrodes, such as one electrode, three electrodes, or four electrodes. 
     In some examples, one or more housing electrodes  124 C may be formed integrally with an outer surface of housing  127  or otherwise coupled to the housing  127 . In some examples, housing electrode  124 C is defined by an uninsulated portion of an outward facing portion of the housing  127  of the IMD  126 . Other divisions between insulated and uninsulated portions of the housing  127  may be employed to define two or more housing electrodes. In some examples, the housing electrode  124 C can include substantially all of the housing  127 . Any of the electrodes  124 A,  124 B may be used for unipolar sensing or pacing in combination with the housing electrode  124 C. As described in further detail with reference to  FIG.  2   , the housing  127  may enclose therapy delivery circuitry, referred to as a stimulation signal generator, that generates cardiac pacing pulses, as well as a sensing module including sensing circuitry for monitoring the patient&#39;s heart rhythm. 
     The configuration of the therapy system  100  illustrated in  FIG.  1    is merely one example. In other examples, a therapy system may include epicardial leads and/or patch electrodes instead of or in addition to the transvenous lead  112  illustrated in  FIG.  1   . Further, the IMD  126  need not be implanted within the patient  116 . In examples in which the IMD  126  is not implanted in the patient  116 , the IMD  12  may deliver therapies to the heart  122  via percutaneous leads that extend through the skin of patient  116  to a variety of positions within or outside of heart  122 . 
     In one or more examples, IMD  126  includes electronic circuitry contained within an enclosure where the circuitry may be configured to deliver cardiac pacing. In the example of  FIG.  1   , the electronic circuitry within IMD  126  may include therapy delivery circuitry electrically coupled to electrodes  124 . The electronic circuitry within IMD  126  may also include sensing circuitry configured to sense electrical activity of heart  122  via electrodes  124 . The therapy delivery circuitry may be configured to administer cardiac pacing via electrodes  124 , e.g., by delivering pacing pulses in response to expiration of a timer and/or in response to detection of the intrinsic activity (or absence thereof) of the heart. 
     In some examples, the system  100  includes an optional programmer  130 . For example, optional programmer  130  can be a handheld computing device such as a tablet or a phone, a computer workstation, or a networked computing device. The optional programmer  130  can include a user interface that receives input from a clinician, which can include a keypad and a suitable display such as, for example, a touch screen display, or a peripheral pointing device, such as a mouse, via which a user may interact with the user interface. The clinician may also interact with the programmer  130  remotely via a networked computing device. 
     The clinician, such as a physician, technician, surgeon, electrophysiologist, and the like, may in some cases interact with the programmer  130  to communicate with the IMD  126 . For example, the clinician may interact with the programmer  130  to retrieve physiological or diagnostic information from the IMD  126 . The clinician may also interact with the programmer  126  to program the IMD  126 , e.g., select values for operational parameters of the IMD. In some examples, the programmer  130  may include an optional electrocardiogram (ECG) monitor. 
     The IMD  126  and the programmer  130  may communicate via wireless communication using any techniques known in the art. Examples of communication techniques may include, for example, low frequency or radiofrequency (RF) telemetry, but other techniques are also contemplated. In some examples, the IMD  126  may signal the programmer  130  to further communicate with and pass information through a network such as those available under the trade designation Medtronic CareLink Network from Medtronic, Inc., of Minneapolis, Minn., or some other network linking the patient  116  to a clinician. 
     In some examples, the system  100  includes an optional electrocardiogram (ECG) monitor  132 . In some methods of the present disclosure, if the programmer  130  is not available, the EGC monitor  132  can provide a clinician with feedback regarding the rhythm and electrical activity of the heart following an IMD implantation procedure. In various examples, the ECG monitor can include one or more leads (not shown in  FIG.  1   ), may include surface electrodes attached to the skin of the patient (not shown in  FIG.  1   ), or may be a wireless monitor without leads. 
       FIG.  2    is a functional block diagram illustrating an example configuration of an example IMD such as the IMD  126  described in  FIG.  1   . In the illustrated example, the IMD  126  includes a processor  80 , a memory  82 , a signal generator  84 , a sensing module  86 , a telemetry module  88 , a ventricular capture management (VCM) module  89 , and power source  90 . The memory  82  includes computer-readable instructions that, when executed by the processor  80 , cause the IMD  126  and the processor  80  to perform various functions described herein. The memory  82  may include any volatile, non-volatile, magnetic, optical, or electrical media, such as a random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically-erasable programmable ROM (EEPROM), flash memory, or any other digital or analog media. 
     Processor  80  may include processing circuitry, such as any one or more of a microprocessor, a controller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field-programmable gate array (FPGA), or equivalent discrete or analog logic circuitry. In some examples, the processor  80  may include multiple components, such as any combination of one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, or one or more FPGAs, as well as other discrete or integrated logic circuitry. The functions attributed to the processor  80  herein may be embodied as software, firmware, hardware or any combination thereof. 
     Processor  80  controls signal generator  84  to deliver therapy to heart  122  according to a selected one or more of therapy programs, which may be stored in memory  82 . For example, processor  80  may control signal generator  84  to deliver electrical pulses with the amplitudes, pulse widths, frequency, or electrode polarities specified by the selected one or more therapy programs. As discussed in more detail below, processor  80  may control the signal generator to pace the heart in a number of different modes including, but not limited to, VOO, VVI, and OVO. 
     Signal generator  84  is electrically coupled to electrodes  124 A,  124 B, e.g., via conductors of lead  120 , or, in the case of housing electrode  124 C, via an electrical conductor disposed within the housing  127  of the IMD  126 . Signal generator  84  includes circuitry, such as capacitors, charge pumps, regulators, current mirrors, and switches, configured to generate and deliver electrical signals to heart  122 . For example, signal generator  84  may deliver pacing stimulation in the form of electrical pulses via the electrodes  124 A-C. Signal generator  84  may include switches, and processor  80  may use the switches to select which of the available electrodes  124  are used to deliver therapy signals. The switches may include a switch array, switch matrix, multiplexer, or any other type of switching device suitable to selectively couple stimulation energy to selected electrodes. 
     Sensing module  86  monitors signals from at least one of electrodes  124 A-C to monitor electrical activity of heart  122 . Sensing module  86  may include electrical sensing circuitry such as filters and amplifiers, as well as an analog-to-digital converter. Sensing module  86  may also include switches to select which of the available electrodes are used to sense the heart activity, e.g., to sense a cardiac EGM, depending upon which electrode combination is used in the current sensing configuration. Sensing module  86  may include one or more detection channels, each of which may be coupled to a respective electrode combination and include an amplifier. The detection channels may be used to sense respective cardiac EGMs. Some detection channels may be configured detect cardiac events, such as, for example, R- or P-waves, or COI parameters, and provide indications of the occurrences of such events to the processor  80 . In some examples, processor  80  detects cardiac events or determines other parameters discussed herein, e.g., COI parameters, based on a digitally converted EGM signal. 
     For generation and delivery of pacing pulses to the heart  122 , processor  80  may utilize programmable counters to control the basic time intervals associated with VOO, OVO, DDD, VVI, DVI, VDD, AAI, DDI, DDDR, VVIR, DVIR, VDDR, AAIR, DDIR and other modes of single and dual chamber pacing. In the aforementioned pacing modes, “D” may indicate dual chamber, “V” may indicate a ventricle, “I” may indicate inhibited pacing (e.g., no pacing), and “A” may indicate an atrium. The first letter in the pacing mode may indicate the chamber that is paced, the second letter may indicate the chamber that is sensed, and the third letter may indicate the chamber in which the response to sensing is provided. The intervals may include atrial and ventricular pacing escape intervals, refractory periods during which sensed P-waves and R-waves are ineffective to restart timing of the escape intervals. Processor  80  may also define a blanking period, and provide signals to the sensing module  86  to blank one or more channels, e.g., amplifiers, for a period during and after delivery of electrical stimulation to heart  122 . The durations of these intervals may be determined by processor  80  in response to stored data in memory  82 . 
     As discussed above, IMD  126  may implement a number of techniques that improve its operation to, for example, verify satisfactory implantation in a way that may be automated and not require programmer  130 . To that end, following attachment of a lead to the IMD  126 , processor  80  may be configured to control IMD  126  to initiate a device test sequence according to qualification test parameters  83  stored in memory  82 . In some examples, the device test sequence(s) are triggered automatically (without further input from the programmer  130  or other device external to the IMD  126 ) after the one or more leads are connected to the IMD. In the device test sequence according to some examples, processor  80  causes IMD  126  to conduct, in series or in parallel, the following qualification tests: 
     (1) detecting an impedance for at least one electrical path that includes the at least one electrode to determine a connection status of the IMD to the at least one electrode and, in some examples, the connection of the electrode to the patient; and 
     (2) comparing EGM amplitudes of, for example, R-waves, over an EGM test period against a predetermined threshold. 
     In some examples, IMD  126  further performs a qualification test (3), which includes determining a pacing capture threshold (PCT) for the IMD. Processor  80  may determine whether a PCT threshold is adequate, e.g., below a threshold. In some examples, the IMD  126  detects a signal indicative of capture during the PCT test and/or a clinician monitors the surface ECG of the patient to determine electrical activity of heart associated with pacing capture. 
     In some examples, the signal generator  84  paces the heart of the patient prior to, during, and/or after performing any of the qualification tests (1)-(3). In some examples, the pacing is in VOO mode (asynchronous ventricular pacing), and in some cases the pacing is in a VVI mode (ventricular demand pacing), but any form of ventricular or atrial pacing may be used. In some examples, IMD  126  operates in OVO mode (no chambers of the heart paced, ventricular sensing only). 
     Once one or more of the qualification tests (1)-(3) are completed in a passing range, in some examples IMD  126  generates an output signal indicating that the qualification tests are complete. In some examples, IMD  126  generates no output signal, but a clinician may observe on a surface ECG that pacing capture threshold (PCT) in qualification test (3) has been successfully performed by the IMD, e.g., based on observing an ECG signal reflecting successful capture of heart by the pacing delivered by IMD  126 . Based on knowledge that successful capture completes the test sequence, the clinician may determine qualification tests have been successfully completed by IMD  126 . 
     In qualification test (1), sensing module  86  and/or processor  80  are capable of collecting, measuring, and/or calculating impedance data according to impedance parameters  81  stored in memory  82  for any of a variety of electrical paths that include two or more of the electrodes  124 A-C. Sensing module  86  may include an impedance measurement module  92  with circuitry configured to measure electrical parameter values during delivery of an electrical signal between at least two of the electrodes. Processor  80  may determine impedance values based on parameter values measured by the impedance measurement module  92 , and store the measured impedance values in the memory  82 . 
     In some examples, processor  80  may perform an impedance measurement by controlling delivery, from the signal generator  84 , of a voltage pulse or other voltage-controlled waveform between selected first and second electrodes  124 . The impedance measurement module  92  may measure a resulting current, and the processor  80  may calculate a resistance based upon the voltage amplitude of the pulse and the measured amplitude of the resulting current. In other examples, the processor  80  may perform an impedance measurement by controlling delivery, from the signal generator  84 , of a current pulse or other current-controlled waveform between first and second electrodes, the measurement module  92  may measure a resulting voltage, and the processor  80  may calculate a resistance based upon the current amplitude of the pulse and the measured amplitude of the resulting voltage. The measurement module  92  may include circuitry for measuring amplitudes of resulting currents or voltages, such as sample and hold circuitry. 
     In these examples, signal generator  84  delivers signals that do not necessarily deliver stimulation therapy to the heart  122 , due to, for example, the amplitudes of such signals and/or the timing of delivery of such signals. For example, these signals may include sub-threshold amplitude signals that may not stimulate the heart  122 . In some cases, these signals may be delivered during a refractory period, in which case they also may not stimulate the heart  122 . IMD  126  may use defined or predetermined pulse amplitudes, widths, frequencies, or electrode polarities for the pulses delivered for these various impedance measurements. 
     In certain cases, IMD  126  may measure impedance values that include both a resistive and a reactive (i.e., phase) component. In such cases, IMD  126  may measure impedance during delivery of a sinusoidal or other time varying signal by signal generator  84 , for example. Thus, as used herein, the term “impedance” is used in a broad sense to indicate any collected, measured, and/or calculated value that may include one or both of resistive and reactive components. 
     Processor  80  may control a plurality of measurements of the impedance of any one or more electrical paths including combinations of electrodes  124 A-C according to the impedance parameters  81  stored therein. In some examples, the processor  80  determines that the qualification test (1) is a pass when processor  80  determines that the impedance measurement module  92  detects an impedance threshold stored in the memory  82 . In some examples, an impedance measurement of about 300Ω to about 2000Ω, or about 300Ω to about 1000Ω, is sufficient to provide a pass for qualification test (1). 
     In some examples, before and during IMD  126  performing the qualification test (1), signal generator  84  paces the heart in VOO mode (ventricular pacing, no sensing). For example, signal generator  84  paces the heart at about 80 beats per minute (bpm). In some examples, signal generator  84  and sensing module  86  may be used to pace the heart in VVI mode (sensed ventricular pacing) prior to the IMD performing the qualification test (1). For example, signal generator  84  may pace the heart at about 60 bpm in response to absence of detection of signals (e.g., detection of the absence of intrinsic R-waves) by sensing module  86 . In some examples, the heart may be paced in VOO or VVI mode in parallel with the IMD performing the impedance measurements in qualification test (1). 
     Processor  80  may control signal generator  84  to deliver the pacing pulses during or after impedance measurement according to the qualification test parameters  83  stored in the memory  82 . For example, processor  80  may control the timing or amplitude of test pulses based on the qualification test parameters  83  which, in some examples, can specify a period of time, e.g., a window, subsequent a pacing pulse or detected cardiac event, which may be an R-wave or a P-wave, or other EGM measurement, noise, an asystolic EGM signal, or the like, in which one or more impedance measurement pulses may be delivered. In some examples, the duration of the period may be selected as appropriate to determine the most accurate impedance values. Furthermore, by controlling the timing of impedance measurement pulses in this manner, IMD  126  may avoid interference with the accuracy of impedance measurements by intrinsic cardiac signals. Processor  80  may compare the impedances measured from each of the test pulses to an impedance threshold, and evaluate the connection and integrity of lead  112  based on the comparison. In some examples, processor  80  may also switch from a current sensing configuration to an alternative sensing or therapy configuration in response to determining a lead related condition or other integrity issue with a configuration. 
     In some examples, IMD  126  repeatedly performs the qualification test (1) until the processor  80  determines a passing impedance measurement over a predetermined time period such as, for example, 2 minutes, 5 minutes, 15 minutes, 30 minutes, 45 minutes or 1 hour. If the measured impedance during the predetermined time period is not within a predetermined passing range, qualification test (1) is determined by the processor  80  to be a failure, and the result is optionally stored in the memory  82 . In some examples, the predetermined passing range is about 300Ω to about 2000Ω, or about 300Ω to about 1000Ω, but the passing range may be set at any appropriate level. If the measured impedance in qualification test (1) is within the passing range, the qualification test (1) is determined by the processor  80  to be a pass, and the result may optionally be stored in the memory  82 . If the qualification test (1) is determined to be a pass, in some examples the processor  80  may cause the signal generator  84  and the sensing module  86  to initiate pacing of the heart in, for example, VVI mode, prior to initiation of qualification tests (2) or (2)-(3). For example, in some cases, the pacing is applied by the IMD to the heart at 60 bpm at a pacing output of about 5 V. 
     In some examples, the following completion of qualification test (1), processor  80  controls IMD  126  to perform qualification test (2). In qualification test (2), processor  80  may detect aspects of EGM signals sensed by sensing module  86  such as, for example, R-waves, P-waves, and COI parameters, according to test criteria  85  stored within the memory  82 . In some examples, the EGM test criteria  85  may include one or more R-wave or P-wave amplitude thresholds, to which the processor  80  may compare amplitudes of sensed R-waves and P-waves. As an example, the suitable EGM threshold may be satisfied by measurable R-waves having an amplitude of at least about 5 mV. If the EGM threshold(s) are satisfied, the qualification test (2) is completed and the processor  80  initiates the optional qualification test (3). If the heart rate is too fast, e.g., whether or not the EGM threshold is determined to be a pass, the processor may repeat one or both of qualification tests (1) and (2), in some examples. 
     In some examples, if processor  80  and sensing module  84  are unable to detect a threshold number of R-waves or other EGM components satisfying the threshold amplitude, processor  80  may lower the pacing rate, e.g., lengthen the escape interval, to allow more intrinsic conduction. For example, processor  80  may decrement the pacing rate, e.g., by steps or otherwise, to minimum rate, e.g., 40 beats per minute (bpm). If the EGM sensing still does not pass the test, processor may change the EGM sensing parameters, e.g., amplitude threshold or electrodes  124  used for sensing. 
     In some examples, processor  80  may perform COI tests according to COI test parameters  85  in the memory  82 , following the completion of the EGM qualification test (2), or in parallel with the EGM qualification test (2). In some examples, sensing module  86  may sense the heart in, for example, OVO mode, prior to initiation of the COI test parameters stored in the memory  82 . Suitable COI parameters  85  in the memory  82  include, but are not limited to, determination of: the maximum amplitude of the ST segment in the EGM of the patient, amplitude of the ST segment 80 milliseconds (ms) from the segment&#39;s beginning, the area under the wave curve (from R-wave start to the end of the ST segment), the area under the ST segment, amplitude at a start of ST segment, median and quartile amplitudes of the first 200 ms following ST segment, amplitude of the R wave, duration of the ST segment, duration of the signal (QT), ratio of R-wave amplitude to maximum amplitude of ST segment, ratio of R-wave amplitude to amplitude of ST segment 80 ms from start, and combinations thereof. 
     In some examples, processor  80  may determine the values of COI parameters based on an analysis of a digitized version of the EGM signal. For example, processor  80  may perform a deconvolution operation of the time-series of EGM samples to recover lower frequency COI content, e.g., emphasize features in the EGM indicative of COI. In some examples, the other EGM signals such as R-wave or P-wave amplitude may be evaluated over the same time period that the COI parameters are determined. If insufficient COI is detected, or if insufficient EGM amplitudes are detected, the qualification test (2) may be terminated by the processor  80 . 
     If processor  80  determines that IMD  126  passes qualification test (2), processor  80  optionally initiates qualification test (3) to evaluate the PCT of IMD  126  according to the PCT/VCM (ventricular capture management) parameters  87  in the memory  82 . In the PCT qualification test, VCM module  89 , sensing module  86 , and signal generator  84  operate according to PCT parameters stored in the memory  82  to evaluate the energy required to cause depolarization and contraction of the heart tissue of the patient, and compares the required energy to a PCT threshold. For example, in some embodiments, the PCT threshold may be evaluated by VCM module  89  to automatically monitor pacing thresholds at periodic intervals. Once the pacing threshold is determined, in some examples VCM module  89  determines a target pacing output based on a predetermined safety margin and a predetermined minimum EGM amplitude. 
     In some examples, processor  80  may run abbreviated VCM tests in which the PCT capture threshold is required to be less than about 2.5 V. In some examples, the processor  80  initiates the signal generator  84  to pace the heart in VVI mode for a predetermined time period (for example, 30 seconds to 60 seconds) to evaluate PCT capture threshold. In some examples, the heart is paced in VVI mode at about 90 bpm to determine the PCT capture threshold. Such a pacing rate is likely faster than the intrinsic heart rate of the patient so that intrinsic heart beats will not interfere with pacing capture threshold testing. 
     If the PCT capture threshold is not achieved, the processor  80  indicates that qualification test (3) was not successful, and the result may optionally be stored in the memory  82 . If the PCT capture threshold is achieved and qualification test (3) is determined to be a pass, in some examples processor  80  may generate a confirmation signal, and a result is optionally stored in the memory  82 . Suitable indications include, for example, energizing a LED, an audible alert, or sending a confirmation signal to an optional programmer  130 . In some examples, processor  80  provides no indication of the status of the qualification test (3), and pacing capture may be evaluated by a clinician as pacing at a fixed rate visible to the clinician on a surface ECG monitor. 
     In some examples, if qualification test (3) is determined to be a pass, IMD  126  switches back to pacing in, for example, OVO mode, for a predetermined period of time (for example, about 6 seconds to about 10 seconds) to allow intrinsic conduction so that sensing module  86  may measure COI parameters. The COI parameters may then be compared to previously measured COI values stored in memory  82 , and if a COI percent change threshold is met, the processor  80  provides an indication that the qualification test (3) and the COI parameters were successful. If the COI percent change threshold fails, the processor  80  instructs the signal generator  84  and the sensing module  86  to switch to pacing in, for example, VVI mode, for a predetermined period of time such as, for example, about 60 seconds. 
     After a selected pacing time of, for example, about 60 seconds, processor  80  may instruct the signal generator  84  and the sensing module  86  to return to OVO mode and the COI parameters are again evaluated and compared the COI values previously stored in memory  82 . For example, the COI values may be compared to stored COI values previously stored in memory  82  from COI measurements completed by IMD  126  minutes to 5 minutes earlier. If the COI percent change threshold is met, processor  80  generates an output indicating that the qualification test (3) and the COI determination were a pass. Otherwise, the processor  80  may output an indication that the COI parameters were not satisfied. 
     The various components of the IMD  126  are coupled to a power source  90 , which may include a rechargeable or non-rechargeable battery. A non-rechargeable battery may be capable of holding a charge for several years, while a rechargeable battery may be inductively charged from an external device, e.g., on a daily or weekly basis. 
       FIG.  3    is a flow diagram illustrating an example of a device test sequence  200  performed by an IMD  126  (for example,  FIG.  1   ) according to the present disclosure. As shown in  FIG.  3   , after IMD  126  detects attachment of lead  112 , processor  80  triggers a device test sequence without input from an external device such as a programmer. IMD  126  may detect attachment of lead  112  based on measuring an impedance consistent with connection to lead  112 . 
     Prior to or at the same time the device test sequence initiates, the signal generator  84  ( FIG.  2   ) paces the ventricle of the heart in VOO mode at a rate of about 80 pulses per minute, and the impedance measurement module  92  performs one or more impedance measurements of the qualification test (1) after each paced event to determine if the measured lead impedance is within a passing range ( 202 ). The one or more impedances within the passing range may indicate one or more of attachment of IMD  126  to lead  112 , integrity of lead  112 , and attachment of lead  112  to the heart. If the qualification test (1) is determined to be a pass (YES of  204 ), processor  80  controls IMD  126  to proceed to qualification test (2). If the measured impedance is outside the passing range (NO of  204 ), the qualification test (1) is deemed to fail, and IMD  126  returns to step  202  to re-initiate the qualification test (1) and search for a passing lead impedance value. As noted above, IMD  126  may continue the qualification test (1) for a predetermined period of time such as, for example, about 30 minutes, or indefinitely until qualification test (1) is determined to be passed (e.g., indicating lead connection and that other qualification tests may proceed). 
     If qualification test (1) is a pass (YES of  204 ), processor  80  triggers the signal generator  84  and the sensing module  86  to perform pacing of the ventricle of the heart of the patient in VVI mode at a rate of 60 bpm and with an R-wave sensitivity of 5 mV ( 206 ). Processor  80  then initiates the qualification test (2) by applying R-wave test criteria  85  stored in the memory  82  ( 208 ). If the measured intrinsic heart rate exceeds a threshold ( 210 ), processor  80  may return to the VOO pacing ( 202 ) and re-runs qualification test (1) ( 204 ). If the R-wave criteria are not met due to too few measured R-waves ( 212 ), processor  80  determines whether the pacing rate has already been decremented to a minimum value, e.g., 40 bpm ( 214 ). If so (YES of  214 ), processor  80  may return IMD  126  to qualification test (1) ( 202 , 204 ) without providing feedback of a successful test. If the pacing rate has not yet been decremented to the minimum value (NO of  214 ), processor  80  decrements the pacing rate ( 218 ) and again attempts to detect and measure R-waves until the R-wave test criteria  85  are satisfied ( 208 ). If excessive processor  80  determines that an amount of noise detected in the EGM signal detected by sensing module  86  during qualification test (2) ( 220 ), the processor may return to the qualification test (1) ( 202 ,  204 ). 
     If the measured EGM amplitudes satisfy the EGM test criteria  85  ( 222 ), the qualification test (2) is deemed a pass. Processor  80  may delay for 30 seconds ( 224 ), and then configured the sensing module  86  and the signal generator  84  to apply pacing to the heart in VVI mode at 90 bpm and 2.5 V for 30 seconds ( 226 ). A clinician may then observe a surface ECG monitor to confirm proper pacing and device capture. The operation of  FIG.  3    thus provides a rapid and simple check on the success of the IMD implantation procedure. 
       FIG.  4    is a flow diagram illustrating another example of a device test sequence  300  performed by an IMD  126  (for example,  FIG.  1   ) according to the present disclosure. As shown in  FIG.  4   , after attachment of at least one lead  112  to IMD  126 , processor  80  triggers a device test sequence without input from an external device such as a programmer. IMD  126  may detect attachment of lead  112  based on measuring an impedance consistent with connection to lead  112 . 
     According to the device test sequence, processor  80  controls signal generator  84  ( FIG.  2   ) to pace the heart in VOO mode at a rate of about 80 pulses per minute ( 302 ) and, e.g., on every paced event, impedance measurement module  92  to measure an impedance to perform the qualification test (1) to determine if the measured lead impedance is within a passing range ( 304 ). The one or more impedances within the passing range may indicate one or more of attachment of IMD  126  to lead  112 , integrity of lead  112 , and attachment of lead  112  to the heart. If the qualification test (1) is determined to be a pass (YES of  304 ), processor  80  controls IMD  126  to proceed to qualification test (2). If the measured impedance is outside the passing range (NO of  304 ), the qualification test (1) is deemed a failure and processor  80  re-initiates the qualification test (1) and searches for a passing lead impedance value ( 302 , 304 ). IMD  126  may continue the qualification test (1) for a predetermined period of time such as, for example, about 30 minutes, or indefinitely. 
     If qualification test (1) is a pass (YES of  304 ), processor  80  triggers signal generator  84  and the sensing module  86  to pace the heart of the patient in VVI mode at a rate of 60 bpm ( 306 ). Processor  80  may then initiate the qualification test (2) by applying R-wave test interval criteria  85  stored in the memory  82  to the EGM sensing by sensing module  86  ( 308 ). If the measured intrinsic heart rate is determined to be too high, e.g., by exceeding a heart rate threshold ( 310 ), processor  80  returns to the VOO pacing ( 302 ), re-runs qualification test (1) ( 304 ). 
     If the R-wave criteria are not met due to too few measured R-waves ( 312 ), processor  80  determines whether the pacing rate has already been decremented to a minimum value, e.g., 40 bpm ( 314 ). If so (YES of  314 ), processor  80  may return IMD  126  to qualification test (1) ( 302 ,  304 ) without confirmation to the clinician or with a signal of non-confirmation ( 317 ). If the pacing rate has not yet been decremented to the minimum value (NO of  314 ), processor  80  may decrement the pacing rate ( 318 ) and sensing module  86  may again attempt to detect and measure R-waves until the EGM test criteria  85  are satisfied ( 308 ). If sensing module  86  detects an amount of noise in the sensed EGM greater than a threshold ( 320 ), processor  80  may return IMD  126  to the qualification test (1) ( 302 ,  304 ) without confirmation to the clinician or with a non-confirmation signal to the clinician ( 317 ). 
     If the R-wave interval criteria  85  are satisfied (YES of  308 ), processor  80  applies an R-wave amplitude test from the EGM test criteria  85  ( 322 ), and determines whether the R-waves meet the criteria, e.g., whether a sufficient number of R-waves were sensed when sensing module  86  applies a threshold of 5 mV ( 324 ). If the sensed R-waves meet the criteria (YES of  324 ), the qualification test (2) is deemed a pass and processor  80  may proceed qualification test (3) ( 326 ). If the sensed R-waves do not meet the 5 mV criteria (NO of  324 ), processor  80  may return IMD  126  to the qualification test (1) ( 302 ,  304 ) without confirmation to the clinician ( 317 ). 
     In qualification test (3), processor  80  may initially perform a rate and stability check ( 326 ). If the check is passed (YES of  326 ), processor  80  may control VCM module  89  to perform an abbreviated VCM test to determine whether capture occurs at or below 2.5V ( 330 ). In capture is confirmed (YES of  332 ), processor  80  may control IMD  126  to provide a confirmation signal ( 334 ), which may include pacing at VVI  90  for 30 seconds ( 336 ). If the VVI pacing protocol is successful as observed on a surface ECG, the qualification test (3) is deemed a pass, and the implant of the IMD is deemed to be successful. If the PCT is outside the target range at 2.5 V (NO of  332 ) or the rate and stability check is not passed (NO of  326 ), the VCM module re-initiates the VCM test, or after a predetermined number of attempts processor  30  controls IMD to provide a non-confirmation signal or returns IMD  126  to the qualification test (1) ( 302 ,  304 ) without confirmation to the clinician ( 317 ). 
       FIG.  5    is a flow diagram illustrating another example of a device test sequence  400  performed by an IMD  126  (for example,  FIG.  1   ) according to the present disclosure. As shown in  FIG.  5   , after attachment of at least one lead to the IMD, the processor  80  triggers a device test sequence without input from an external device such as a programmer. IMD  126  may detect attachment of lead  112  based on measuring an impedance consistent with connection to lead  112 . 
     According to the device test sequence, processor  80  controls signal generator  84  and sensing module  86  ( FIG.  2   ) pace the heart in VVI mode at a rate of about 60 bpm ( 402 ). Based on beats being paced according to the VVI mode, processor  80  transitions IMD  126  to VOO pacing, and controls impedance measurement module  92  measure impedance to determine if the measured lead impedance is within a passing range ( 404 ). The one or more impedances within the passing range may indicate one or more of attachment of IMD  126  to lead  112 , integrity of lead  112 , and attachment of lead  112  to the heart. If the measured impedance does not satisfy the impedance criteria (N of  404 ), processor  80  may control IMD  126  to resume pacing according to the VVI mode. 
     If qualification test (1) is a pass (YES of  404 ), processor controls IMD  126  to return to the VVI mode. For intrinsic beats that are sensed during pacing in the VVI mode, processor  80  may control sensing module  86  to perform qualification test (2) by applying an interval measurement in the EGM test criteria  85  stored in the memory  82  for sensing intrinsic beats ( 408 ). If the measured heart rate is too high, e.g., above a threshold rate, processor  80  returns continues pacing in the VVI mode ( 410 ). If the R-wave criteria are not met due to too few intrinsic R-waves ( 412 ), processor  80  determines whether the pacing rate is at a minimum value, e.g., 40 bpm ( 414 ). If the pacing rate is not at the minimum (NO of  414 ), processor  80  may decrement the pacing rate ( 418 ) and continue VVI pacing and monitoring for intrinsic R-waves. If the pacing rate has already been decremented to 40 bpm (YES  414 ), processor  80  may provide a non-confirmation signal in step  417  that qualification test (2) is not a pass, and re-initiate qualification tests (1 and 2) ( 402 ,  404 , and  408 ). 
     If processor  80  determines that an amount of noise in the EGM exceeds a threshold ( 420 ), the processor may control impedance measurement module  92  to measure impedance and determine whether the measurement is valid ( 422 ). If the measured lead impedance is valid (YES of  422 ), processor  80  may issue a non-confirmation signal  417  and re-initiate qualification tests (1 and 2) ( 402 ,  404 , and  408 ). If the measured impedance is not valid (NO of  422 ), processor  80  may control IMD  126  to switch to VOO pacing, e.g., at a rate of 80 bpm ( 424 ), and determine whether the measured impedances meet impedance criteria  81  ( 404 ). 
     If the sensed R-waves satisfy interval criteria of test criteria  85 , processor  80  applies an R-wave amplitude test from the EGM test criteria  85  ( 428 ). Processor  80  determines whether one or more R-wave amplitudes are greater than a threshold, e.g., 5 mV, and the impedance check from qualification test (1) is a pass ( 430 ). If criteria of qualification tests (1) and (2) are met (YES of  430 ), processor  80  proceeds to perform a capture management rate and stability check ( 432 ). If the measured R-wave amplitude(s) do not meet the 5 mV threshold (NO of  430  and  434 ), processor  80  causes IMD  126  to return the non-qualification signal ( 417 ), and may return to VVI pacing at 60 bpm ( 402 ). If the measured R-wave amplitude(s) do meet the 5 mV threshold, but the impedance check was not a pass (NO of  430  and YES  434 ), processor  80  may control IMD  126  to transition to VOO pacing at 80 bpm and control impedance measurement module  92  to measure impedances ( 436 ). If the impedance check is not a pass (NO of  437 ), processor  80  returns the non-confirmation signal ( 417 ), and may return to VVI pacing at 60 bpm ( 402 ). If the impedance check is a pass (YES of  437 ), processor  80  proceeds to perform a capture management rate and stability check ( 432 ). 
     If the rate and stability check is passed (YES of  432 ), processor  80  may control VCM module  89  to perform an abbreviated VCM test to determine whether capture occurs at or below 2.5V ( 440 ). Processor  80  sets ventricular pacing output to 2.5V and the PCT is evaluated by the VCM module  89 . In capture is confirmed (YES of  442 ), processor  80  may control IMD  126  to provide a confirmation signal ( 444 ), which may include pacing at VVI  90  for 30 seconds ( 446 ). If the VVI pacing protocol is successful as observed on a surface ECG, the qualification test (3) is deemed a pass, and the implant of the IMD is deemed to be successful. If capture is not observed/detected at 2.5 V (NO of  442 ) or the rate and stability check is not passed (NO of  432 ), the VCM module re-initiates the VCM test, or after a predetermined number of attempts processor  80  controls IMD to provide a non-confirmation signal ( 417 ) or returns IMD  126  to the qualification tests (1 and 2) and VVI pacing ( 402 ) with a signal of confirmation to the clinician ( 417 ). 
       FIG.  6    is a flow diagram illustrating another embodiment of a device test sequence  500  performed by an IMD  126  (for example,  FIG.  1   ) according to the present disclosure. IMD  126  is attached to lead  112  ( 501 ), and processor  80  triggers a device test sequence without input from an external device such as a programmer. According to the sequence  500 , processor  80  controls impedance measurement module  92  to measure impedances according to qualification test (1) to determine if the measured lead impedance is within a passing range ( 502 ). The one or more impedances within the passing range may indicate one or more of attachment of IMD  126  to lead  112 , integrity of lead  112 , and attachment of lead  112  to the heart. If the qualification test (1) is determined to be a pass (YES of  502 ), processor  80  proceeds to qualification test (2) ( 504 ). If the measured impedance is outside the passing range (NO of  502 ), processor  80  may re-initiate the qualification test (1) and search for a passing lead impedance value ( 502 ). Processor  80  may continue the qualification test (1) for a predetermined period of time such as, for example, about 30 minutes, or indefinitely. 
     According to qualification test (2), processor  80  may control IMD  126  to enter an OVO mode and sensing module  86  to sense intrinsic R-wave amplitudes and COI parameters ( 504 , 506 ). As noted above, COI parameters  85  can include the maximum amplitude of the ST segment, the amplitude of the ST segment 80 ms from the segment&#39;s beginning, the area under the wave curve (from R-wave start to the end of the ST segment), the area under the ST segment, amplitude at a start of ST segment, median and quartile amplitudes of the first 200 ms following ST segment, amplitude of the R wave, duration of the ST segment, duration of the signal (QT), ratio of R-wave amplitude to maximum amplitude of ST segment, ratio of R-wave amplitude to amplitude of ST segment 80 ms from start, and combinations thereof. If insufficient COI is detected after an evaluation period of about 6 seconds, processor  80  outputs that the implant failed ( 508 ). If an insufficient R-wave amplitude is detected, e.g., after an evaluation period of 6 seconds, processor  80  outputs that the implant failed ( 510 ). 
     Otherwise, processor  80  controls IMD  126  to switch to pacing in VVI mode for 60 seconds to evaluate pacing capture threshold (PCT) in qualification test (3) ( 512 ). If there is not proper capture as measured by the VCM module  89 , processor outputs that implant has failed ( 508 ). If there is proper capture, processor  80  controls IMD  126  to switch back to OVO mode for a period of 6 seconds to calculate COI parameters ( 514 ). The COI parameter values are compared to the values from a time period before current values, such as 1 minute, 5 minutes, or 10 minutes. If the COI percent change threshold is met, processor  80  outputs that the implant passed ( 516 ). If the COI percent change threshold fails, processor  80  controls IMD  126  to pace in VVI mode for 60 seconds ( 518 ). 
     After 60 seconds of pacing, processor  80  returns IMD  126  to OVO mode to calculate COI parameters again ( 520 ). The parameters are compared to the initial values from 2 minutes before. If the COI percent change threshold is met, processor  80  outputs that the implant passed ( 516 ). Otherwise, processor  80  outputs that the implant failed ( 508 ). 
       FIGS.  7 A- 7 C  are a flow diagrams illustrating another example of a device test sequence  600  performed by an IMD  126  (for example,  FIG.  1   ) according to the present disclosure. After attachment of at least one lead  112  to IMD  126  ( 601 ), the processor  80  triggers a device test sequence without input from an external device such as a programmer. While in a single chamber asynchronous mode such as VOO or a single chamber demand pacing mode such as VVI, processor  80  controls impedance measurement module  92  to measure impedances to perform the qualification test (1) to determine if the measured lead impedance is within a passing range ( 602 ). The one or more impedances within the passing range may indicate one or more of attachment of IMD  126  to lead  112 , integrity of lead  112 , and attachment of lead  112  to the heart. If the measured impedance is outside the passing range (NO of  602 ), the qualification test (1) is deemed to be a failure, and processor  80  may, after a delay ( 603 ) re-initiate the qualification test (1) and search for a passing lead impedance value ( 602 ). Processor  80  may repeat performance of qualification test (1) after an impedance test interval of about 15 seconds to about 30 seconds. Processor  80  may continue the qualification test (1) for a predetermined period of time such as, for example, about 30 minutes, or indefinitely. 
     If the qualification test (1) is determined to be a pass (YES of  602 ), processor  80  may switch IMD  126  to operation in the OVO mode, and the sensing module  86  may sense intrinsic R-wave amplitudes and COI parameters for qualification test (2) ( 604 ). As noted above, these COI parameters  85  can include determining any or all of the following: the maximum amplitude of the ST segment, the amplitude of the ST segment 80 ms from the segment&#39;s beginning, the area under the wave curve (from R-wave start to the end of the ST segment), the area under the ST segment, amplitude at a start of ST segment, median and quartile amplitudes of the first 200 ms following ST segment, amplitude of the R wave, duration of the ST segment, duration of the signal (QT), ratio of R-wave amplitude to maximum amplitude of ST segment, ratio of R-wave amplitude to amplitude of ST segment 80 ms from start, and combinations thereof. 
     If R-wave amplitude sensing is determined to be insufficient (NO of  605 ), qualification test (2) is determined to be a failure. If R-wave amplitude sensing is determined to be sufficient (YES of  605 ), processor  80  switches IMD  126  to pacing in VVI mode for a period of time such as 30 or 60 seconds ( 606 ), and proceeds to perform the impedance check of qualification test (1) ( 608 ). To avoid intrinsic cardiac interference, in some examples VOO pacing may performed instead of VVI pacing for this impedance measurement. If the impedance check of qualification test (1) is determined to be out of a passing range (NO of  608 ), processor  80  assumes that a lead is being repositioned or reconnected to the IMD and waits ( 603 ) prior to performing another impedance check ( 602 ). 
     If the impedance is within a passing range (YES of  608 ), processor  80  again implements VVI pacing for 30 seconds ( 610 ) and re-checks impedance ( 612 ). If the impedance is in a passing range (YES of  612 ), processor  80  switches to OVO mode for a period of about 6 seconds, and calculates any or all of the COI parameters discussed above with respect to step  604  ( 614 ). 
     Processor  80  controls IMD  126  to initiate overdrive pacing in VVI mode for 30 seconds to evaluate device capture at 1.5 V for PCT qualification test (3) ( 616 ). If there is not proper capture at 1.5V as measured by the VCM module  89  (NO of  618 ), processor  80  outputs that the implant failed ( 619 ). If there is proper capture (YES of  618 ), processor  80  again controls performance of impedance measurements for qualification test (1) ( 620 ). If the impedance is within a predetermined passing range (YES of  620 ), processor  80  controls IMD  126  to pace the heart in VVI mode for 30 seconds ( 622 ), and then again checks impedance ( 624 ). 
     If the impedance remains in the passing range (YES of  624 ), processor  80  switches IMD  126  back to OVO mode for a period of 6 seconds to calculate COI parameters ( 626 ). Processor  80  compares the COI parameters to the previously measured COI values from steps  604  and  614  ( 628 ). If the COI percent change threshold is met (YES of  628 ), processor outputs an indication that the implant passed ( 630 ). If the COI percent change threshold is not met (NO of  628 ), processor  80  may indicate that the IMD implantation failed ( 629 ). 
     It should be noted that the therapy system  100  may not be limited to treatment of a human patient. In alternative examples, the therapy system  100  may be implemented in non-human patients, e.g., primates, canines, equines, pigs, and felines. These other animals may undergo clinical or research therapies that my benefit from the subject matter of this disclosure. 
       FIG.  8    is a conceptual drawing illustrating an example configuration of another IMD  700 , which may be configured to automatically trigger performance of diagnostic self-tests and provide rapid feedback to the practitioner to support a procedure to implant the IMD, e.g., in the manner described herein with respect to IMD  126  and  FIGS.  4 - 7 B . 
     As shown in  FIG.  8   , IPD  700  includes case  730 , cap  738 , electrode  740 , electrode  732 , fixation mechanisms  742 , flange  734 , and opening  736 . Together, case  730  and cap  738  may be considered the housing of IMD  700 . In this manner, case  730  and cap  738  may enclose and protect the various electrical components, e.g., a processor, signal generator, sensing module, impedance measurement circuitry, VCM module, memory, telemetry module, and other circuitry as described with respect to  FIG.  2   , within IMD  700 . IMD  700  may a plurality of electrodes (e.g., electrodes  732  and  740 ) for delivery and sensing of electrical signals. 
     Electrodes  732  and  740  are carried on the housing created by case  730  and cap  738 . In this manner, electrodes  732  and  740  may be considered leadless electrodes, and IMD  700  may be considered a leadless IMD, e.g., a leadless pacemaker or leadless pacing device. In the example of  FIG.  8   , electrode  740  is disposed on the exterior surface of cap  738 . Electrode  740  may be positioned to contact cardiac tissue upon implantation. Electrode  732  may be a ring or cylindrical electrode disposed on the exterior surface of case  730 . Both case  730  and cap  738  may be electrically insulating. 
     Electrode  740  may be used as a cathode and electrode  732  may be used as an anode, or vice versa, for delivering cardiac pacing such as bradycardia pacing, CRT, ATP, or post-shock pacing. However, electrodes  732  and  740  may be used in any stimulation configuration. In addition, electrodes  732  and  740  may be used to detect intrinsic electrical signals, e.g., from cardiac muscle. 
     Fixation mechanisms  742  may attach IMD  700  to tissue, e.g., cardiac tissue. Fixation mechanisms  742  may be active fixation tines, screws, clamps, adhesive members, or any other mechanisms for attaching a device to tissue. As shown in the example of  FIG.  8   , fixation mechanisms  742  may be constructed of a memory material, such as a shape memory alloy (e.g., nickel titanium), that retains a preformed shape. During implantation, fixation mechanisms  742  may be flexed forward to pierce tissue and allowed to flex back towards case  730 . In this manner, fixation mechanisms  742  may be embedded within the target tissue. Flange  734  may be provided on one end of case  730  to enable tethering or extraction of IMD  700 . 
     IMD  700 , e.g., processor  80  of IMD  700 , may be configured to detect placement of the IMD into a patient and, in response to placement of the IMD into the patient, to initiate a device test sequence, comprising any of the a plurality of qualification tests disclosed herein, over an evaluation period. Processor  80  may be configured to detect positioning of IMD  700  within patient based on a change in impedance measured by impedance measurement circuitry  92  via electrodes  732  and  740  when the electrodes are exposed to blood and/or come into contact with tissue. For the test sequence, processor  80  may control IMD  700  to perform qualification tests including measurement of impedance, comparison of EGM amplitudes to a threshold, evaluation of pacing capture, determining COI parameters, or any one or more of the tests described herein. 
     The techniques described in this disclosure, including those attributed to the IMDs  126  and  700 , the programmer  130 , or various constituent components, may be implemented, at least in part, in hardware, software, firmware or any combination thereof. For example, various aspects of the techniques may be implemented within one or more processors, including one or more microprocessors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or any other equivalent integrated or discrete logic circuitry, as well as any combinations of such components, embodied in programmers, such as physician or patient programmers, stimulators, image processing devices or other devices. The term “processor” or “processing circuitry” may generally refer to any of the foregoing logic circuitry, alone or in combination with other logic circuitry, or any other equivalent circuitry. 
     Such hardware, software, firmware may be implemented within the same device or within separate devices to support the various operations and functions described in this disclosure. In addition, any of the described units, modules or components may be implemented together or separately as discrete but interoperable logic devices. Depiction of different features as modules or units is intended to highlight different functional aspects and does not necessarily imply that such modules or units must be realized by separate hardware or software components. Rather, functionality associated with one or more modules or units may be performed by separate hardware or software components, or integrated within common or separate hardware or software components. 
     When implemented in software, the functionality ascribed to the systems, devices and techniques described in this disclosure may be embodied as instructions on a computer-readable medium such as random access memory (RAM), read-only memory (ROM), non-volatile random access memory (NVRAM), electrically erasable programmable read-only memory (EEPROM), FLASH memory, magnetic data storage media, optical data storage media, or the like. The instructions may be executed to support one or more aspects of the functionality described in this disclosure. 
     Various examples have been described. These and other examples are within the scope of the following claims. 
     EMBODIMENTS 
     Embodiment A. A method comprising: 
     detecting, by an implantable medical device (IMD), attachment to the IMD of at least one implantable medical lead, wherein the at least one implantable medical lead comprises at least one electrode; and 
     triggering by the IMD, based on the detecting of the attachment to the IMD of the at least one medical lead, a device test sequence in which the IMD performs the following qualification tests over an evaluation period: 
     (1) detecting an impedance for at least one electrical path that includes the at least one electrode to determine a connection status of the IMD to the at least one electrode; and 
     (2) comparing EGM (electrogram) amplitudes of the patient over an EGM test period against a predetermined threshold. 
     Embodiment B. The method of Embodiment A, wherein the device test sequence further comprises a qualification test (3), monitoring pacing capture threshold (PCT) of the IMD.
 
Embodiment C. The method of Embodiments A to B, wherein qualification tests (1)-(2) are performed sequentially.
 
Embodiment D. The method of any of Embodiments A to C, wherein qualification tests (1)-(2) are performed in parallel.
 
Embodiment E. The method of any of Embodiments A to D, wherein qualification tests (2)-(3) are performed following qualification test (1).
 
Embodiment F. The method of any of Embodiments B to E, wherein the IMD measures current of injury (COI) parameters in an EGM of the patient prior to, during, or after, qualification test (3).
 
Embodiment G. The method of any of Embodiments A to F, wherein the IMD measures current of injury (COI) parameters following qualification test (1).
 
Embodiment H. The method of any of Embodiments A to G, wherein the IMD measures current of injury (COI) parameters following qualification test (1), and in parallel with qualification test (2).
 
Embodiment I. The method of any of Embodiments B to H, wherein if the IMD passes any of the qualification tests (1)-(3) over the evaluation period, the IMD generates a confirmation signal.
 
Embodiment J. The method of any of Embodiments A to I, wherein the IMD automatically initiates the device test sequence, without input from an external programmer, when the at least one implantable lead is connected to the IMD.
 
Embodiment K. The method of any of Embodiments A to J, wherein an impedance passing range for the qualification test (1) is about 300Ω to about 2000Ω.
 
Embodiment L. The method of any of Embodiments A to K, wherein the evaluation period is about 2 minutes to about 1 hour following attachment of the at least one lead to the IMD.
 
Embodiment M. The method of any of Embodiments A to L, wherein the evaluation period is about 5 minutes to about 30 minutes after attachment of the at least one lead to the IMD.
 
Embodiment N. The method of any of Embodiments A to M, wherein the IMD paces the heart of the patient in a single chamber asynchronous mode prior to or during performance of the device test sequence.
 
Embodiment O. The method of Embodiment N, wherein the IMD paces the heart at a fixed rate of at least 80 pulses per minute.
 
Embodiment P. The method of any of Embodiments A to O, wherein the IMD performs single chamber demand pacing on the heart of the patient prior to or during performance of the device test sequence.
 
Embodiment Q. The method of Embodiment P, wherein the demand pacing is delivered at a rate of about 60 pulses per minute.
 
Embodiment R. The method of any of Embodiments A to Q, further comprising generating, by the IMD, an alert confirming termination of the device test sequence.
 
Embodiment S. The method of any of Embodiments A to R, wherein if the impedance detected by the IMD in qualification test (1) is within an impedance passing range, the IMD paces the heart of the patient in a single chamber demand mode.
 
Embodiment T. The method of Embodiment S, wherein the IMD paces the heart at about 60 bpm in VVI mode at a pacing output of about 5 V.
 
Embodiment U. The method of Embodiment S, wherein the IMD paces the heart at 60 bpm in AAI mode at a pacing output of about 1 V.
 
Embodiment V. The method of any of Embodiments A to U, wherein the qualification test (2) runs over an EGM test period of at least 30 seconds.
 
Embodiment W. The method of any of Embodiments A to V, wherein if the IMD measures an R-wave amplitude, or an average or a median R-wave amplitude, of at least about 5 mV over the EGM test period, the IMD terminates qualification test (2).
 
Embodiment X. The method of any of Embodiments A to W, wherein if the IMD measures a P-wave amplitude, or an average or a median P-wave amplitude, of at least about 1 mV over the EGM test period, the IMD terminates qualification test (2).
 
Embodiment Y. The method of any of Embodiments A to X, wherein if the IMD measures a R-wave amplitude, or an average or a median R-wave amplitude, of less than about 5 mV over the EGM test period, the IMD re-starts qualification test (2).
 
Embodiment Z. The method of any of Embodiments A to Y, wherein if the IMD measures a P-wave amplitude, or an average or a median P-wave amplitude, of at least about 1 mV over the EGM test period, the IMD re-starts qualification test (2).
 
Embodiment AA. The method of any of Embodiments A to Z, wherein if the IMD determined no sensed cardiac events in a predetermined time period, the IMD terminates qualification test (2).
 
Embodiment BB. The method of any of Embodiments A to AA, wherein the IMD performs qualification test (2) on a predetermined number of cardiac sensed events having the lowest measured amplitudes.
 
Embodiment CC. The method of any of Embodiments A to BB, wherein following termination of qualification test (2) is a pass, the IMD paces a heart of the patient in single chamber demand mode.
 
Embodiment DD. The method of Embodiment CC, wherein the IMD paces the heart at 90 bpm in single chamber demand mode for about 30 seconds.
 
Embodiment EE. The method of Embodiment DD, wherein the IMD paces the heart in VVI mode at a pacing output of about 2.5 V.
 
Embodiment FF. The method of Embodiment DD, wherein the IMD paces the heart in AAI mode at a pacing output of about 1 V.
 
Embodiment GG. The method of any of Embodiments B to FF, wherein qualification test (3) comprises pacing, by the IMD, of a heart of the patient in single chamber demand mode.
 
Embodiment HH. The method of any of Embodiments A to GG, wherein the IMD paces the heart in VVI mode at 2.5V for about 30 seconds to about 60 seconds.
 
Embodiment II. The method of any of Embodiments A to HH, wherein the IMD paces the heart in AAI mode at 1 V for about 30 seconds to about 60 seconds.
 
Embodiment JJ. The method of any of Embodiments E to II, wherein the IMD measures the current of injury (COI) parameters in an electrogram of the patient by performing at least one of the following steps: determining a maximum amplitude of an ST segment, determining an amplitude of the ST segment 80 milliseconds from a beginning of the segment, determining an area under a wave curve from an R-wave start to the end of the ST segment, and determining an area under the ST segment.
 
Embodiment KK. The method of Embodiment JJ, wherein the COI parameters are determined in OVO or VVI mode.
 
Embodiment LL. The method of Embodiments JJ to KK, wherein the COI parameters are determined in OVO mode or VVI mode after completion of the qualification test (3), and wherein the IMD determines the COI parameters over a predetermined interval.
 
Embodiment MM. The method of Embodiment LL, wherein the predetermined interval is about 6 seconds.
 
Embodiment NN. A method comprising:
 
     detecting, by an implantable medical device (IMD), attachment to the IMD of at least one implantable medical lead, wherein the at least one implantable medical lead comprises at least one electrode; 
     triggering by the IMD, based on the detecting of the attachment of the at least one implantable medical lead, a device test sequence in which the IMD performs the following steps over an evaluation period: 
     (1) delivering a pacing stimulus to a heart of the patient in a single chamber asynchronous mode; 
     (2) prior to or during step (1), periodically detecting an impedance for at least one electrical path that includes the at least one electrode, and determining, based on whether the impedance detected by the IMD is within a passing range, a connection status of the IMD to the at least one electrode; 
     (3) pacing the heart of the patient in demand mode; 
     (4) comparing, over an EGM test period, cardiac sensed event amplitudes in an electrogram of the heart of the patient over an EGM test period against a predetermined threshold; and 
     (5) pacing the heart of the patient in demand mode to determine a pacing capture threshold (PCT). 
     Embodiment 00. The method of Embodiment NN, wherein following completion of the steps (1)-(5) over an evaluation period, generating by the IMD a confirmation signal.
 
Embodiment PP. The method of Embodiments NN to OO, comprising pacing by the IMD the heart of the patient in single chamber asynchronous mode at a fixed rate of at least 80 pulses per minute prior to or after performing the device test sequence.
 
Embodiment QQ. The method of any of Embodiments NN to PP, wherein in step (3) the IMD paces the heart of the patient at 60 bpm in VVI mode at a pacing output of about 5 V.
 
Embodiment RR. The method of any of Embodiments NN to QQ, wherein in step (3) the IMD paces the heart of the patient at 60 bpm in AAI mode at a pacing output of about 1 V.
 
Embodiment SS. The method of any of Embodiments NN to RR, wherein in step (5) the IMD paces the heart of the patient at 90 bpm in VVI mode for 30 seconds at a pacing output of about 2.5 V to determine a device capture.
 
Embodiment TT. The method of an of Embodiments NN to SS, wherein in step (5) the IMD paces the heart of the patient at 90 bpm in AAI mode for 30 seconds at a pacing output of about 1 V to determine a device capture.
 
Embodiment UU. A method comprising:
 
     detecting, by an implantable medical device (IMD), attachment to the IMD of at least one implantable medical lead, wherein the at least one implantable medical lead comprises at least one electrode; 
     triggering by the IMD, based on the attachment to the IMD of the at least one implantable medical lead, a device test sequence in which the IMD performs the following steps over an evaluation period: 
     (1) pacing a heart of the patient in single chamber demand mode; 
     (2) periodically detecting an impedance for at least one electrical path that includes the at least one electrode, and determining, based on whether the impedance detected by the IMD is within a predetermined range, a connection status of the IMD to the at least one electrode; 
     (3) comparing, over an EGM test period, cardiac sensed event amplitudes in an electrogram of the patient over an EGM test period against a predetermined threshold; and 
     (4) pacing the heart of the patient, for a predetermined time period, in single chamber demand mode to determine a pacing capture threshold (PCT). 
     Embodiment VV. The method of Embodiment UU, wherein steps (2) and (3) are performed in parallel.
 
Embodiment WW. The method of Embodiments UU to VV, wherein the IMD generates a confirmation signal when steps (1)-(4) are complete.
 
Embodiment XX. The method of any of Embodiments UU to WW, wherein the evaluation period is about 2 minutes to about 1 hour.
 
Embodiment YY. The method of any of Embodiments UU to XX, wherein if step (2) results in an impedance measurement outside a passing range of about 300Ω to about 2000Ω, the 1 MB paces the heart of the patient in single chamber asynchronous mode.
 
Embodiment ZZ. The method of any of Embodiments UU to YY, wherein if impedance detected by the IMD is outside the impedance passing range of about 300Ω to about 2000Ω, the 1 MB returns to step (1) and repeats step (2) until the IMD detects an impedance in the passing range.
 
Embodiment AAA. The method of any of Embodiments UU to ZZ, wherein IMD paces the heart of the patient at 60 bpm at a pacing output of about 2.5V in VVI mode in step (1).
 
Embodiment BBB. The method of any of Embodiments UU to AAA, wherein IMD paces the heart of the patient at 60 bpm at a pacing output of about 1V in AAI mode in step (1).
 
Embodiment CCC. The method of any of Embodiments UU to BBB, wherein the IMD performs step (3) over an EGM test period of at least 30 seconds.
 
Embodiment DDD. The method of Embodiment CCC, wherein if the R-wave amplitude measured by the IMD is at least about 5 mV over the EGM test period, the IMD terminates the EGM test sequence.
 
Embodiment EEE. The method of any of Embodiments UU to DDD, wherein if the R-wave amplitude measured by the IMD is less than about 5 mV over the EGM test period, the IMD re-starts the EGM test sequence.
 
Embodiment FFF. The method of Embodiment CCC, wherein if the P-wave amplitude measured by the IMD is at least about 1 mV over the EGM test period, the IMD terminates the EGM test sequence.
 
Embodiment GGG. The method of any of Embodiments UU to FFF, wherein if the P-wave amplitude measured by the IMD is less than about 1 mV over the EGM test period, the IMD re-starts the EGM test sequence.
 
Embodiment HHH. The method of any of Embodiments UU to GGG, wherein the IMD measures cardiac sensed events, and terminates the test sequence if the number of cardiac sensed events is less than a predetermined threshold.
 
Embodiment III. The method of any of Embodiments UU to HHH, wherein the IMD performs the EGM test sequence on a predetermined quantity of the measured cardiac sensed events with the lowest amplitudes.
 
Embodiment JJJ. The method of any of Embodiments UU to III, wherein the IMD paces the heart of the patient at 90 bpm at 2.5 V in VVI mode for 30 seconds in step (4) to determine capture of the device.
 
Embodiment KKK. The method of any of Embodiments UU to JJJ, wherein the IMD paces the heart of the patient at 90 bpm at 1 V in AAI mode for 30 seconds in step (4) to determine capture of the device.
 
Embodiment LLL. A method comprising:
 
     detecting, by an implantable medical device (IMD), attachment to the IMD of at least one implantable medical lead, wherein the at least one implantable medical lead comprises at least one electrode; 
     triggering by the IMD, based on the detecting of the attachment of the at least one implantable medical lead a device test sequence in which the IMD performs the following steps over an evaluation period: 
     (1) delivering a pacing stimulus to a heart of the patient in single chamber asynchronous mode; 
     (2) periodically detecting an impedance for at least one electrical path that includes the at least one electrode, and determining, based on whether the impedance detected by the IMD is within a passing range, a connection status of the IMD to the at least one electrode; 
     (3) pacing the heart of the patient in single chamber demand mode; 
     (4) comparing, over an EGM test period, cardiac sensed event amplitudes in an electrogram of the patient over an EGM test period against a predetermined threshold; and 
     (5) pacing the heart of the patient in single chamber demand mode. 
     Embodiment MMM. The method of Embodiment LLL, wherein an impedance passing range for the device test sequence (2) is about 300Ω to about 2000Ω.
 
Embodiment NNN. The method of Embodiments LLL to MMM, wherein the evaluation period is about 15 minutes to about 1 hour.
 
Embodiment OOO. The method of Embodiments LLL to NNN, wherein the IMD paces the heart of the patient in a single chamber asynchronous mode prior to or during step (1) at a fixed rate of at least 80 pulses per minute.
 
Embodiment PPP. The method of any of Embodiments LLL to OOO, wherein the IMD paces the heart of the patient at 60 bpm at a pacing output of about 5 V in VVI mode in step (3).
 
Embodiment QQQ. The method of any of Embodiments LLL to PPP, wherein the IMD paces the heart of the patient at 60 bpm at a pacing output of about 1 V in AAI mode in step (3).
 
Embodiment RRR. The method of any of Embodiments LLL to QQQ, wherein the IMD runs step (4) over an EGM test period of about 5 seconds to about 30 seconds.
 
Embodiment SSS. The method of Embodiment RRR, wherein if a measured R-wave amplitude is at least about 5 mV over the EGM test period, the IMD terminates step (4).
 
Embodiment TTT. The method of Embodiment RRR, wherein if a measured R-wave amplitude is less than about 5 mV over the EGM test period, the IMD re-starts the EGM test sequence; or moves to step (5) and re-starts the EGM test sequence at a later time.
 
Embodiment UUU. The method of Embodiment RRR, wherein if a measured P-wave amplitude is at least about 1 mV over the EGM test period, the IMD terminates step (4).
 
Embodiment VVV. The method of Embodiment RRR, wherein if a measured P-wave amplitude is less than about 1 mV over the EGM test period, the IMD re-starts the EGM test sequence; or moves to step (5) and re-starts the EGM test sequence at a later time.
 
Embodiment WWW. The method of Embodiment RRR, wherein the IMD measures the number of cardiac sensed events, and terminates the EGM test sequence if a measured heart rate is less than a predetermined value.
 
Embodiment XXX. The method of Embodiment RRR, wherein the IMD performs the R-wave test sequence on a predetermined quantity of the measured cardiac sensed events with the lowest amplitudes.
 
Embodiment YYY. The method of Embodiment RRR, wherein the IMD performs the P-wave test sequence on a predetermined quantity of the measured cardiac sensed events with the lowest amplitudes.
 
Embodiment ZZZ. The method of any of Embodiments LLL to YYY, wherein the IMD paces the heart of the patient at 90 bpm in VVI mode for 30 seconds at a pacing output of about 2.5 V in step (5) to determine a qualification of pacing capture threshold (PCT).
 
Embodiment AAAA. The method of any of Embodiments LLL to ZZZ, wherein the IMD paces the heart of the patient at 90 bpm in AAI mode for 30 seconds at a pacing output of about 1 V in step (5) to determine a qualification of pacing capture threshold (PCT).
 
Embodiment BBBB. A method comprising:
 
     detecting, by an implantable medical device (IMD), attachment to the IMD of at least one implantable medical lead, wherein the at least one implantable medical lead comprises at least one electrode; 
     triggering by the IMD, based on the detecting of the attachment to the IMD of the at least one medical lead, a device test sequence in which the IMD performs the following steps: 
     (1) periodically detecting an impedance for at least one electrical path that includes the at least one electrode, and determining, based on whether the impedance detected by the IMD is within a passing range, a connection status of the IMD to the at least one electrode; 
     (2) sensing a ventricle of the heart in OVO mode; 
     (3) comparing, in OVO mode, over an EGM test period, cardiac sensed event amplitudes in an electrogram of the patient over an EGM test period against a predetermined threshold; 
     (4) measuring, in OVO mode, current of injury (COI) parameters in the electrogram of the patient; and 
     (5) pacing the heart of the patient in VVI mode to determine a pacing capture threshold. 
     Embodiment CCCC. The method of Embodiment BBBB, wherein steps (3)-(4) are performed in parallel.
 
Embodiment DDDD. The method of any of Embodiments BBBB to CCCC, wherein the IMD paces the heart in VVI mode for about 5 seconds to about 30 seconds in step (5).
 
Embodiment EEEE. The method of Embodiment DDDD, wherein following step (5), the IMD performs device test sequence step (4) in OVO mode.
 
Embodiment FFFF. The method of Embodiment DDDD, wherein the IMD performs steps (3)-(4) sequentially until the PCT is determined.
 
Embodiment GGGG. The method of Embodiment FFFF, wherein the IMD performs step (4) for a predetermined time and compares a measured COI value to the measured COI value obtained in a previous time period.
 
Embodiment HHHH. The method of Embodiment DDDD, wherein the IMD measures current of injury (COI) parameters in an electrogram of the patient by determining at least one of the following: a maximum amplitude of an ST segment, an amplitude of the ST segment 80 milliseconds from a beginning of the segment, an area under a wave curve from an R-wave start to the end of the ST segment, and an area under the ST segment.
 
Embodiment IIII. A method for implanting a prosthetic heart valve in a heart of a patient, the method comprising:
 
     detecting, by an implantable medical device (IMD), attachment to the IMD of at least one implantable medical lead, wherein the at least one implantable medical lead comprises at least one electrode; 
     triggering by the IMD, based on the detecting of the attachment to the IMD of the at least one medical lead, a device test sequence in which the IMD performs the following steps: 
     (1) detecting an impedance for at least one electrical path that includes the at least one electrode to determine a connection status of the IMD to the at least one electrode; 
     (2) comparing, over an EGM test period, cardiac sensed event amplitudes in an electrogram of the patient over an EGM test period against a predetermined threshold; and 
     (3) monitoring pacing capture threshold (PCT); and 
     delivering, during or after performance by the IMD of the device test sequence, a valve component in a radially compressed delivery configuration to a location within a native heart valve; and 
     deploying the valve component such that the valve component expands from the radially compressed delivery configuration to a radially expanded deployed configuration. 
     Embodiment JJJJ. The method of Embodiment IIII, wherein the IMD performs qualification tests (1)-(2) sequentially.
 
Embodiment KKKK. The method of any of Embodiments IIII to JJJJ, wherein the IMD performs qualification tests (1)-(2) in parallel.
 
Embodiment LLLL. The method of any of Embodiments IIII to KKKK, wherein the IMD performs qualification tests (2)-(3) following completion of qualification test (1).
 
Embodiment MMMM. The method of any of Embodiments IIII to LLLL, wherein the IMD measures current of injury (COI) parameters in an electrogram of the patient prior to, during, or after, step (3).
 
Embodiment NNNN. The method of Embodiment MMMM, wherein the IMD measures the COI parameters following the completion of qualification test (1).
 
Embodiment OOOO. The method of Embodiment MMMM, wherein the IMD measures the COI parameters following the completion of qualification test (1), and in parallel with qualification test (2).
 
Embodiment PPPP. The method of Embodiment MMMM, wherein if the IMD completes the qualification tests (1)-(3) over the evaluation period, the IMD generates a confirmation signal.
 
Embodiment QQQQ. A system comprising:
 
     at least one implantable medical lead comprising one or more electrodes; 
     an implantable medical device (IMD) coupled to the at least one lead, wherein the at least one lead senses a cardiac electrogram (EMG) signal of a patient via the electrodes; and 
     wherein the IMD comprises a processor that causes the IMD to initiate following coupling to the at least one lead, a device test sequence in which the IMD performs any of the methods of claims  1 - 94 . 
     Embodiment RRRR. The system of Embodiment QQQQ, wherein the IMD comprises an impedance measurement module, and the processor controls the impedance measurement module to measure in qualification test (1) an impedance of each of one or more electrical paths that include the electrodes on the at least one implantable medical lead.
 
Embodiment SSSS. The system of Embodiments QQQQ to RRRR, further comprising an external programmer that presents an alert to a user in response to one or more of the qualification tests.
 
Embodiment TTTT. The system of Embodiment SSSS, wherein the external programmer displays an EGM of the patient.
 
Embodiment UUUU. The system of any of Embodiments QQQQ to TTTT, further comprising an electrocardiogram (ECG) monitor.
 
Embodiment VVVV. The system of any of Embodiments QQQQ to UUUU, wherein the IMD comprises at least one of a temporary or permanent pacemaker, a cardioverter, and a defibrillator.
 
Embodiment WWWW. The system of any of Embodiments QQQQ to VVVV, wherein the IMD comprises a stimulation module, and the processor causes the stimulation module to pace a heart of a patient prior to or after detecting a lead impedance in a passing range.
 
Embodiment XXXX. The system of any of Embodiments QQQQ to WWWW, wherein the IMD comprises a stimulation module, and the processor causes the stimulation module to initiate cardiac pacing prior to initiation of the device test sequence.
 
Embodiment YYYY. The system of Embodiment XXXX, wherein the stimulation module paces the heart in VOO, AOO, VVI or AAI mode.
 
Embodiment ZZZZ. The system of any of Embodiments QQQQ to YYYY, wherein the processor causes the IMD to measure current of injury (COI) parameters in an electrogram of the patient.
 
Embodiment AAAAA. A computer-readable medium comprising instructions that cause a processor to:
 
     following connection of the implantable medical device (IMD) to at least one lead, the lead comprising an electrode, controlling the IMD to automatically initiate, without input from an external programming device, a device test sequence in which the IMD performs the following qualification tests over an evaluation period: 
     (1) detecting an impedance for at least one electrical path that includes the at least one electrode to determine a connection status of the IMD to the at least one electrode; and 
     (2) comparing, over an EGM test period, cardiac sensed event amplitudes in an electrogram of the patient over an EGM test period against a predetermined threshold. 
     Embodiment BBBBB. The computer-readable medium of Embodiment AAAAA, wherein the processor controls the IMD to perform a qualification test (3): monitoring pacing capture threshold (PCT).
 
Embodiment CCCCC. The computer readable medium of Embodiments AAAAA to BBBBB, wherein the processor further causes the IMD to monitor current of injury (COI) parameters in an electrogram of the patient.