Physiological measuring system comprising a garment in the form of a sleeve or glove and sensing apparatus incorporated in the garment

A measuring system for measuring electrocardiogram signals comprises a diagnostic garment with ECG electrodes that may assume the form of a sleeve or glove. A disposable version of the glove can be inflated. By using an inflatable glove, the contour of the body is automatically matched by the contour of the glove. Samples from the ECG electrodes positioned on a diagnostic garment are compensated so that the samples better approximate samples from EEG electrodes that are positioned at classical locations. Also, samples from ECG electrodes are compensated to reduce signal noise resulting from positioning the ECG electrodes on the diagnostic garment.

BACKGROUND OF THE INVENTION

The field of the invention is in the design of devices for the acquisition, storage and transmission of multiple physiological parameters from human subjects to be monitored in hospitals, clinics, doctor's offices as well as in remote locations (home environment, work place, recreational activity, etc.) or unnatural environments (under-water, outer space, etc.).

The conventional acquisition of a human electrocardiogram (ECG) requires the recording of the time dependent fluctuations in the cardiac electrical activation from 12 different angles on the human torso (6 in the frontal plane and 6 in the horizontal plane) the so-called 12 lead ECG. Classically, this procedure involves the placement on the human body of at least 10 electrodes at various predefined anatomical locations.

Deviation from the predefined, worldwide, conventional localization of these electrodes may result in the acquisition of false data, possibly leading to misinterpretation and misdiagnosis. Even in the hospital or clinic environment, the correct and stable placement of the ECG electrodes, specifically the “chest leads” or “V leads” is often problematic, unless one applies six adhesive electrodes on the patient's chest. This is an impractical method in many circumstances due mainly to financial and patient inconvenience considerations. This problem is amplified in the attempts to record a full diagnostic 12 lead ECG in a remote location since the correct positioning of the electrodes by the examinee himself or by available laymen bystanders (family members, friends, etc.) is usually difficult and unreliable and therefore impractical.

To overcome this problem and to allow for the accurate acquisition of a 12 lead ECG in the ambulatory environment, various devices were conceived. Such devices include various forms of vests, girdles, adhesive and non-adhesive patches and other devices with incorporated electrodes allowing for the placement of the ECG electrodes on the patient's chest. However, most of these devices are cumbersome to use and have therefore not been universally accepted. Moreover, these devices do not lend themselves to the integration of other sensors and instrumentation for the simultaneous acquisition of other important physiological data (blood pressure, Sp02, etc.), such data being very useful for the purpose of ambulatory telemedical follow-up of patients in their own environment (home, workplace, recreational activity, etc).

SUMMARY OF THE INVENTION

The invention proposes to integrate a multitude of sensors and measuring devices in a diagnostic garment in the form of a glove or sleeve for repeated continuous and simultaneous assessment of various physiological data such as ECG, noninvasive blood pressure (NIBP), blood oxygen saturation (Sp02), skin resistance, motion analysis, an electronic stethoscope, etc. An important advantage of the glove or sleeve is that it provides accurate, repeatable and conventional placement or localization of the ECG electrodes (specifically for the recording of the chest or V leads) by positioning the left arm of patient in a natural and very comfortable manner on the chest. Moreover, the glove or sleeve provides a means for simultaneous recording, storage and transmission of a multitude of other physiological data without the need for difficult manipulations. Furthermore, the incorporation of various measuring tools or instruments into one device, i.e. glove or sleeve, allows for the reciprocal calibration and easy acquisition of important, integrated, physiological data, a feature presently almost unavailable in the ambulatory environment (e.g. beat to beat NIBP changes, integration of: heart rate, blood pressure, skin resistance and other parameters for the assessment of autonomic balance, etc.).

With one aspect of the invention, samples from the ECG electrodes positioned on a diagnostic garment (e.g., a glove or sleeve) are compensated so that the samples better approximate samples from EEG electrodes that are positioned at classical locations. With an embodiment of the invention, a first mean QRS vector is selected from a first plurality of mean QRS vectors associated with standard electrodes and second mean QRS vector is selected from a second plurality of mean QRS vectors associated with the diagnostic garment.

With another aspect of the invention, samples from ECG electrodes are compensated to reduce signal noise that may result by positioning the ECG electrodes on the diagnostic garment.

With another aspect of the invention, a disposable version of the glove can be inflated. By using an inflatable glove, the contour of the body is automatically matched by the contour of the glove. The matching contours will allow for a close fit between the electrodes and the skin.

A further aspect of the invention relates to the inflatable glove which is capable of assuming the contour of the body and which is also disposable. The contoured glove incorporates electrodes and thereby may enable appropriate positioning of ECG electrodes.

Another aspect of the invention is the design of the inflatable glove which may be incorporated with a sling or a similar device such as a sleeve or holder will be separable from and capable of appropriately positioning and holding the inflatable glove.

These and other objects, advantages, features and aspects of the invention will be set forth in the detailed description which follows.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

As depicted inFIGS. 2-5, the garment of the invention is preferably in the form of a glove or sleeve or combined glove and sleeve10and is fabricated from flexible material such as a nylon fabric that can fit snugly, without causing discomfort, on a human hand, forearm and arm. The glove or sleeve10is sized to fit or conform to patient arm size and shape. A neck sling12is attached to the glove or sleeve10. The neck sling12is also adaptable and adjustable to the individual patient to ensure accurate positioning or elevation of the left arm on the chest of the patient for the proper placement of the ECG electrodes. Moreover, the neck sling12may include an additional ECG electrode14(FIG. 5).

Two blood-pressure cuffs16,18are incorporated in the glove or sleeve10. One cuff16is positioned on the arm in the conventional blood-pressure measuring location, the second cuff18is placed on the forearm. Special restraining straps20mounted on the outside of the glove are wrapped around the blood-pressure cuffs16,18to allow proper restrainment during cuff inflation. The blood-pressure cuffs16,18are connected by a flexible tube22,23to a central control unit or device24for inflation, deflation, and measurement of blood pressure by conventional methodology and used in the automatic determination of NIBP.

At least ten ECG electrodes30are attached to the glove or sleeve10as depicted inFIG. 3. All of the ECG electrodes30except the LA electrode face the patient's chest whereas the LA electrode30is in contact with the skin of the left upper arm. The RA electrode30or its equivalent is placed either on the index finger of the glove10in the neck sling12, or in another suitable position. All of the electrodes30are wire connected to the ECG recording device located in the central control unit24retained in the sleeve10.

The ECG electrodes30included the following features:(a) An automatic electrolyte solution application device. In the course of the recording of a conventional ECG, it is the routine to manually apply an electrolyte solution or cream to the contact surface between the skin and the recording electrodes to cause a reduction of skin resistance and to improve the conduction of the electrical current between the skin and the according electrode. In the described glove or sleeve10, each electrode30includes means for automatic injection of an electrolyte solution into each electrode30prior to the acquisition of the ECG. This is achieved by connection of each electrode to an electrolyte reservoir by means of connecting tubes32. Prior to the acquisition of the ECG recording, the electrolyte solution will be automatically sprayed into the electrodes30by pressure provided by a pump located in the central control unit24.(b) A suction device for better electrode-skin contact: The ECG electrodes30will be configured as suction electrodes30and will be connected via suction tubes34to a pump located in the central control unit24. Once the glove or sleeve10is placed on the chest in the proper position, an external signal will activate the pump to create the needed negative pressure and suction to maintain the proper electrode-skin contact. Following the termination of the ECG recording, the negative pressure will be abolished allowing detachment of the electrodes from the patient's chest. The same or separate pumps may be utilized to effect electrolyte application and the creation of electrode suction.

A conventional IR SpO2 measuring device36is incorporated in the glove or sleeve10and placed on one of the glove finger tips38to fit the patient's finger. Blood SpO2 is determined using the conventional methods applied for this measurement and the results will be stored in the central control unit24.

A conventional finger Plethysmographic-measuring device38is incorporated in one of the glove fingertips40to fit on the patient's finger. An external restraining device42ensures continuous snug contact with the finger to provide continuous beat to beat changes in finger blood volume variation. The finger plethysmograph is wire connected to the central control unit24. The signal is periodically calibrated using the conventional cuff blood pressure measurements thereby allowing for continuous beat to beat blood pressure monitoring.

A thermistor44is incorporated in the glove or sleeve10and located on the ventral surface of the arm in direct contact with the skin to allow the determination of skin temperature. The thermistor44is wire connected to the central control unit24.

A conventional sensor46for the determination of skin resistance is incorporated in the glove or sleeve10and wire connected to the central control unit24.

Two special microphones50,52are attached to the ventral aspect of the glove or sleeve10, one located over the base of the left lung and the second on one of the fingers for the simultaneous auscultation of both lungs. Furthermore, the finger microphones50,52can also be moved to enable auscultation of the heart and other organs. The microphones50,52will be connected to the central control unit24for recording and transmission of the auscultatory findings.

Motion and force assessment devices60,80,82are incorporated in the glove or sleeve10mainly for the early detection of neurological and neuromuscular dysfunction. Sensors60assess passive and active functions such as:(a) Force of muscular contraction (e.g., handgrip, arm flexion and extension, etc.)(b) Passive pathological arm and finger motion (Parkinsonian tremor, flapping tremor, etc.).(c) Assessment of active finger, hand or arm motion (rapid hand pronation and supination, rapid finger motion, etc.).

The glove or sleeve10is equipped with a central control unit24attached to the dorsal aspect of the glove or sleeve10(FIG. 2). The general function of this unit24is the collection, transformation, storage and transmission of all of the physiological data collected from the various devices incorporated in the glove10. Moreover, the central control unit24includes mechanical and other devices such as pumps, injectors, etc., needed for the proper functioning of the incorporated devices as described herein.

Specifically, the central control unit24includes the appropriate measuring element for each sensor. The measured data is digitized, stored and upon demand, made available for transmission by RF or IR or any other form of wireless telemetric transmission to a remote surveillance center. Conversely, the central control unit24has the ability to receive signals from a remote surveillance center for the activation or deactivation and other control functions of the various measuring devices incorporated in the glove10.

In review, the glove10provides an unobtrusive stable platform for self-application of numerous physiological sensors using a glove and/or sleeve10and an optional neck support sling12to perform various simultaneous non-invasive on invasive health-care related measurements for use in the home, workplace, recreational, clinic or hospital environment. The invention has the advantage over other methods of sensor applications in that no prior knowledge of proper sensor placement is required and that proper placement of the sensors on the patient is assured. The sensor position is stable and reproducible. The invention improves the repeatability of measurements by insuring that the placement and distances between the various sensors remain constant. Moreover, the interplay between the various sensors can result in the combination of data acquisition integration and analysis adding major sophistication and improvement as compared to the individual use of each measuring devices.

In further review, the glove/sleeve10together with the optional neck support sling12contains one or more of the following measuring elements:(a) An optical emitter and detector36attached to the index finger of the glove10for the purpose of measuring the level of oxygen saturation in the blood, and peripheral pulse (FIG. 2).(b) A finger plethysmograph device38for continuous, beat to beat, noninvasive arterial blood pressure measurement (calibrated by the mean of the arterial blood pressure determinations derived from both the wrist and arm NIBP devices) (FIG. 2).(c) Inflatable cuff and pressure cuffs or sensor16,18located in various locations on the arm and hand to measure brachial radial or finger blood pressure for periodic (automatic or manual) noninvasive blood pressure measurements (NIBP). These NIBP measuring devices are also used to calibrating the optical system used to measure continuous, beat to beat arterial blood pressure as above mentioned (FIG. 2).(d) A central control unit24for the acquisition and transmission of the various bio-signals derived from the glove sensors. This central control unit24which can be activated locally by the patient or remotely by a monitoring center allows for automatic or manual activation of any or all of the sensors. The central control unit24provides amongst other: the initial and repeated sensor calibration procedures, activation of a built-in miniature pump for the creation of positive and negative pressures, the reception of commands from the remote control center, analog to digital conversion of measured data and their transmission to the control center as well as any other needed control functions (FIG. 2).(e) A set of electrodes30(V1, V2, RA, RL) placed on the palmar aspect of the glove10and/or the neck support sling12for the purpose of simultaneous recording of a twelve-lead electrocardiogram (FIG. 3).

(f) A method for automatic administration of an electric conductor solution/cream to the electrodes30to reduce skin resistance and improve ECG relating quality.(g) A method of producing and maintaining a sufficient negative pressure (suction) inside the ECG electrodes30to insure proper contact between the ECG electrode and the skin (FIG. 3).(h) A method of insuring proper contact between the ECG electrodes30and the skin by the application of an air cushion or a gel cushion around areas of the glove that are in contact with the skin. The cushion is used to provide a body contour fit (FIG. 3).(i) A method such as a buckle connection15to adjust the sling12to ensure that the arm is held at the proper level for accurate placement of the ECG electrodes30on the patients body.(j) A temperature sensor40placed in appropriate areas of the glove/sleeve10for the purpose of measuring body temperature (FIG. 4).(k) An electrode or set of electrodes46placed in the palm area of the glove for the purpose of measuring skin resistance (FIG. 4).(l) An electronic stethoscope for the auscultation of lungs, heart and other organs.(m) Built-in measuring devices80inFIG. 4in the glove fingers for the accurate assessment of tremor and other normal or neurological forms of finger motions.(n) Built in measuring devices80in the glove10for the determination of EMG.(o) Built-in measuring devices80in the glove10for the determination of nerve conduction.(p) Built-in measuring device82for the determination of muscle force (hand grip, extension, flexion, etc.).(q) Built-in device82for the assessment of rapid/accurate voluntary hand movement.(r) The advised positioning of the patient's left arm on the chest to ensure proper localization of the 12 lead ECG electrodes of the glove for accurate and reproducible 12 lead ECG recording is shown inFIG. 5. This arm position, aided by the adjustable neck support sling12, is natural and comfortable and therefore allows for prolonged, stable and continuous monitoring of all available parameters (FIG. 5).

FIGS. 6,7,8and9are schematic drawings depicting the basic elements described above.FIG. 6depicts the various sensors including the SpO2 sensor36, the plethysmography sensor38, the temperature sensor44, skin resistance probes46, strain gauges48, and stethoscope sensors50,52. As depicted inFIG. 6, each of the inputs in amplified and, if necessary, filtered prior to being converted to a 24 bit analog to digital converter. The output of the analog to digital converter goes via a control ASIC depicted inFIG. 9to a dual port ram also inFIG. 9where it is processed and transmitted by a microprocessor and an infrared communications to a stationary unit.

FIG. 7depicts the various mechanical elements and connections for the ECG electrodes and the blood pressure mechanical and electronic portion of the system. Each ECG electrode comprises a container that holds a saline solution or another lubricant. This solution is drawn into the electrode via a vacuum system. A bleed valve closes the system and then releases the vacuum. The release of the vacuum will then release the lubricant or solution. Digital input output drivers control the vacuum pump and the bleed valve in response to signals that are provided from the ASIC control lines. In the embodiment disclosed, there are two blood pressure cuffs, one associated with the wrist and one with the upper arm. A blood pressure pump (NIBP pump) pumps each cuff. A pressure sensor then measures the pressure in each cuff. The values from the pressure sensor are amplified, filtered and converted to digital values in the 24-bit analog to digital converter. The output of the analog to digital converter also passes through the control ASIC inFIG. 9to the dual port random access memory unit where it is processed and transmitted by the microprocessor and IR communications, for example, to a stationary unit.

FIG. 8depicts the ECG analog input circuitry. Each electrode input is separately amplified and ban passed filtered prior to conversion by a 24-bit analog to digital converter. The analog to digital converter signal passes through the control ASIC inFIG. 9to the dual port RAM where it is processed and transmitted again by the microprocessor and IR communications to a stationary unit.

FIG. 9depicts the digital circuitry in the system. The circuitry includes the ASIC which has logic for the timing signals and for transmitting or passing the digitized analog signals from the various analog to digital converters to the dual port RAM which sits on the microprocessor. The microprocessor runs the software provided from the flash memory, collects data samples, performs basic analysis, controls the various valves and pumps and sends data to the central data collector via IR communication. The described circuitry is but one way to accomplish the goals and objectives of the use of the glove and/or sleeve of the invention.

Electrode Compensation

Embodiments of the invention enhance a vector representation of the ECG waveforms. As will be discussed, methods and apparatuses provide for adjusting a vector representation of ECG signals to compensate for positioning ECG electrodes on a diagnostic garment (e.g., the glove/sleeve as discussed above) rather than classically positioning the electrodes on a patient's limbs as with standard ECG electrodes. Also, an embodiment of the invention compensates for additional signal noise that may be imposed on the EEG signals resulting from the positioning of the EEG electrodes on the diagnostic garment.

Cardiac activity generates a measurable amount of electric current. The current is recorded through an electrocardiograph and displayed as an EEG waveform, the shape of which is governed by both the magnitude and direction of the current flow. The EEG waveforms may be displayed as vectors whose trajectories also depict the magnitude and direction of the heart's impulses as will be discussed withFIG. 11. The average of these vectors for a particular heart cycle is called the mean QRS vector and is displayed on a vector image as a solid arrow whose length is the average magnitude and whose angle is the average direction.

FIG. 10shows a simplified representation1000of an exemplary ECG waveform that is obtained from an ECG lead in accordance with an embodiment of the invention. In normal sinus rhythm, each P wave1001is followed by a QRS complex (comprising Q wave1003, R wave1005, and S wave1007). The QRS complex represents the time it takes for depolarization of the ventricles. Activation of the anterioseptal region of the ventricular myocardium corresponds to the negative Q wave1003. However, Q wave1003is not always present. Activation of the rest of the ventricular muscle from the endocardial surface corresponds to the remainder of the QRS complex. The R wave1005is a point when half of the ventricular myocardium has been depolarized. Activation of the posteriobasal portion of the ventricles give an RS line. The normal QRS duration is approximately from 0.04 seconds to 0.12 seconds measured from the initial deflection of the QRS complex from the isoelectric line to the end of the QRS complex. The QRS complex precedes ventricular contraction.

FIG. 11shows an ECG waveform and an associated vector representation in accordance with an embodiment of the invention.FIG. 11shows QRS complex1101being represented as vectors1003(in relation to Einthoven's triangle1107as will be discussed) whose trajectories also depict the magnitude and direction of the heart's impulses. The average of these vectors for a particular heart cycle is called mean QRS vector1105and is displayed on the vector image as a solid arrow whose length is the average magnitude and whose angle is the average direction. QRS complex1109corresponds to a subsequent heart cycle that can be presented by another set of vectors.

Experimental studies involving hundreds of patients compare 12-lead ECG recordings with both standard electrodes and with electrodes positioned on a diagnostic garment. The diagnostic garment may assume a garment that fits on a portion of a patient's body and may assume a form of a glove/sleeve as shown inFIGS. 2 and 3. An exemplary embodiment of the invention utilizes PhysioGlove™, which is a glove/sleeve that fits over a patient's left arm and left hand.

The standard “12 lead ECG” utilizes the three standard limb bipolar leads (lead I, lead II, and lead III), three augmented limb leads, and six precordial unipolar leads. The augmented leads are the same as the standard leads, except that the augmented leads are compared to a hypothetical null value that corresponds to a central point over the heart where no fluctuations in potential can be measured. The null point is actually mathematically determined using the electrical potentials generated by the other 2 leads. The lead on the left arm is known as an aVL lead, the lead on the right arm as an aVR lead, and the lead on the left leg as an aVF lead. Precordial leads are leads fanning across the chest. Precordial leads (V1, V2, V3, V4, V5, and V6) give more specific information about electrical conduction in the heart than the limb leads.

Comparing the locations of EEG electrodes30on diagnostic garment10shown inFIG. 3and the classic positioning of ECG electrodes as shown inFIG. 1, one observes that the locations of the corresponding EEG electrodes are different. In order to better approximate the signals from the classic positioning of ECG electrodes, the ECG signals from the EEG electrodes on diagnostic garment10may be compensated as will be discussed. In particular, experimental studies indicate variations in the EEG waveform are caused by positioning the LL electrode on diagnostic garment10rather than on the left leg.

FIG. 12shows an Einthoven's triangle1200representing (modeling) ECG leads1207,1209, and1211in accordance with an embodiment of the invention. Lead I1207represents the electrical potential between LA (left leg) electrode1203and RA (right arm) electrode1201. Lead II1209represents the electrical potential between LL (left leg) electrode1205and LA electrode1203. Lead III1211represents the electrical potential between LL electrode1205and RA electrode1201. (RA electrode1201, LA electrode1203, and LL electrode1205correspond to RA, LA, and LL electrodes30shown inFIG. 3.) From Einthoven's triangle1200, one can determine one lead from the other two leads by the following relationships:
LeadI=LeadII−LeadIII(EQ. 1A)
LeadII=LeadI+LeadIII(EQ. 1B)
LeadIII=LeadII−LeadI(EQ. 1C)

Null point1219is a hypothetical “null” value that exits at a central point over the heart where no fluctuations in potential can be measured. The “null point” is actually mathematically determined using the electrical potentials generated by leads1207,1209, and1211. Augmented leads aVR1213(corresponding to the right arm), aVL1215(corresponding to the left arm), and aVF1217(corresponding to the left leg) are measured with respect to null point1219. Augmented leads1213,1215, and1217can be expressed in terms of standard leads1207,1209, and1211. For example, aVF can be expressed as:
aVF=0.5*LeadI+LeadIII(EQ. 1D)

Experimental results suggest that the mean QRS vector representing the QRS complex obtained from the patients using the diagnostic garment varies when compared with the mean QRS vector obtained from patients using standard electrodes. Experimental results also suggest that when these differences are compensated for, one can obtain an ECG waveform analogous to the one obtained using the standard electrode configuration.

FIG. 13shows a vector diagram1303for determining compensation parameters in accordance with an embodiment of the invention. Analyzing a plurality of QRS complexes, vector1301is the selected mean QRS vector with standard electrodes (corresponding to the ECG electrodes shown inFIG. 1) and vector1303is the selected mean QRS vector with electrodes positioned on the diagnostic garment (e.g., glove/sleeve10as shown inFIG. 2). The selection of mean QRS vectors will be discussed. Angle1351(Φ−α) and angle1353(α) are used to determine a compensation factor as will be discussed.

An analysis of the mean vector of the QRS complex is made from any two of the three standard leads. In the embodiment, leads I and III are used. However, other embodiments of the invention can use lead II and lead III or lead I and lead II. The compensation process is a two-stage procedure with each stage involving a series of steps:

Stage I—Determine Compensation Parameters:Select an ECG time interval with several QRS complexes.Find the average vector angle for these QRS complexes. Each QRS complex is associated with a mean QRS vector (e.g., vector1105as shown inFIG. 11). A first plurality of mean QRS vectors is associated with the standard electrode configuration (as shown inFIG. 1) and a second plurality of mean QRS vectors is associated with the garment electrode configuration (as shown inFIG. 3).Select the QRS complex with the angle closest to the average. A first selected mean QRS vector is selected that is closest to the average of the first plurality of mean QRS vectors and a second mean QRS vector is selected that is closest to the average of the second plurality of mean QRS vectors.Find the compensation coefficient (k1), where
k1=Cos Φ/Cos(Φ−α)  (EQ. 2)This coefficient will be used in Stage II for performing the compensation. The angles Φ and Φ−α correspond to the angles shown inFIG. 13.

Stage II—Apply the Compensating Algorithm:The glove is a DSP device transmitting N samples per second to the receiver where N is the sample rate.Each sample contains Lead I and Lead III voltages.The other limb leads are combinations of these two leads.

During Stage 2, the limb lead values are compensated using the following matrix formula:

(Lead⁢INewLead⁢IIINew)=kA-1⁢BA⁡(Lead⁢ILead⁢III)⁢⁢where⁢(Lead⁢ILead⁢III)⁢⁢and⁢⁢(Lead⁢INewLead⁢IIINew)(EQ.⁢3)
are the columns of lead voltages before and after the compensation, respectively. The compensation associated with Equation 3 uses the following matrix values:

Matrix A has an inverse

A-1=(10-0.51).
The compensation coefficient k1is defined in Equation 2. The determined compensation is applied to every ECG sample provided by the diagnostic garment. The compensated waveforms/reports are hence obtained.

While the exemplary embodiment selects one of the mean QRS vectors closest to an average of a plurality of mean QRS vectors, another embodiment can select a resulting mean QRS vector with another criterion. Also, another embodiment may determine a resulting mean QRS vector that corresponds to an average of the plurality of mean QRS vectors even though the resulting mean QRS vector does not correspond to actual measurement data.

The electrical signal from the heart's natural pace maker starts in what is called the SA (sinoatrial) node located in the right atrium travels through the right atrium to the ventricles (i.e. the lower chambers of the heart). The electrical signals cross a junction called the AV (atrialventricular) node going from the atruim to the ventricles. From the AV node the electrical signal travels through a path called the bundle of His that splits into two paths one on the left lower chamber and one on the right lower chamber. Each path is called a bundle branch. The electrical signals from the bundle branches causes the ventricles to contract. Normally both ventricles contract simultaneously. If one of the bundle branches is damaged then the blockage blocks or slows the electrical signal on one of the paths. The blockage of the electrical signal is called a bundle branch block. A left bundle branch block (LBBB) blocks the signal on the left side while a right bundle branch block (RBBB) blocks the signal on the right side. Patients that have a bundle branch block do not require compensation as described above. Thus, a separate algorithm may be used to detect those patients so that their ECG waveforms are not compensated.

ECG waveform noise reduction is performed in two stages, in which the signal noise results from positioning the ECG electrodes on the diagnostic garment.

Stage I—Determine the Parameter for the Compensation FilterSelect an ECG time interval with several QRS complexes.Calculate Mod_Lead I=V6−V1values. Electrodes V6and V1are positioned on the diagnostic garment as shown inFIG. 3.Define the AVG (R(Lead I)) and AVG (R(Mod_Lead I)) for the selected time interval. R is a parameter representing the height of the QRS complex peak over the isoelectric line. R is a parameter representing the height of the QRS complex peak over the isoelectric line. In the embodiment, R corresponds to the height of the R wave1005as shown inFIG. 10.Determine the compensation coefficient k2, where
k2=AVG(R(LeadI))/AVG(R(Mod_Lead I))  (EQ. 7)The compensation coefficient k2will be used in Stage II for performing the compensation.

Stage II—Apply the Compensating Algorithm

The glove transmits Lead I, Lead III, and V1to V6voltages. Lead potential VL, which is a voltage between the LL electrode and the center of Einthoven's triangle, is given by.
VL=LL−(LL+LA+RA)/3  (EQ. 8)

VL voltage may also be obtained from the combination of the existing leads:
VL=(LeadI+2*LeadIII)/3  (EQ. 9)

The compensated values for Lead I and Lead III are determined by:
Lead INew=k2*(V6−V1)  (EQ. 10)
LeadIIINew=−k2*(V6−V1)/2+3/2(VL)  (EQ. 11)

where Lead INewand Lead IIINeware values after compensation, VL is the previously defined voltage, and k2is the compensation coefficient.

FIG. 14Ashows a flow diagram1400for compensating for the positioning of ECG electrodes on a diagnostic garment in accordance with an embodiment of the invention. If step1401determines that a patient is diagnosed with a bundle branch block (as previously discussed), then compensation of the ECG inputs is circumvented through step1413. If not, step1403selects a first mean QRS vector that is closest to a first plurality of mean QRS vectors, each corresponding to a QRS complex with a standard electrode configuration. Step1405selects a second mean QRS vector that is closest to a second plurality of mean QRS vectors, each corresponding to a QRS complex with a garment electrode configuration. In step1407, an angle α between the two selected mean QRS vectors is determined as shown inFIG. 13. In step1409, an angle Φ−α between the first selected mean QRS vector and a reference axis corresponding to Lead I is determined. In step1411, a compensation coefficient k1(as given by EQ. 2) is determined. Procedure1400continues to step1413in order to process subsequent samples.

FIG. 14Bshows a continuation of flow diagram1400, in which the compensation coefficient k1is used to compensate subsequent ECG samples obtained from the electrodes positioned on the diagnostic garment. (ECG samples are acquired every 1/N seconds, i.e., N samples per second. A sample comprises ECG measurements from a plurality of ECG electrodes as shown inFIG. 3.) Step1415determines if a new sample is available for Lead I (corresponding to LA1203minus RA1201as shown inFIG. 12) and for Lead III (corresponding to LL1205minus LA1203as shown inFIG. 12). If so the voltages for Lead I and Lead III are compensated using Equations 3-6 in step1417. In Step1419, the voltage for Lead II is determined using EQ. 1B. Steps1415-1419are repeated for each subsequent ECG sample.

FIG. 15Ashows a flow diagram1500for compensating for signal noise resulting from the positioning of ECG electrodes on a diagnostic garment in accordance with an embodiment of the invention. Process1500determines compensation coefficient k2in order to reduce signal noise induced by positioning ECG electrodes on the diagnostic garment, e.g., glove/sleeve10. Step1501determines if all QRS complexes have been processed. If so, step1509determines compensation coefficient k2using Equation 7. If not, step1503processes the next QRS complex.

In step1505, a modified Lead I value is determined. With step1507the height of the R wave1005(as shown inFIG. 10) is determined for both Lead I and the modified Lead I (Mod_Lead I). Process1500is repeated until all QRS complexes are processed. In step1511, once compensation coefficient k2is determined, process1500continues to process subsequent ECG samples as shown inFIG. 15B.

FIG. 15Bshows a continuation of flow diagram1500. If step1513determines that a new ECG sample is available for processing, lead potential VL is calculated with Equation 9 using Lead I and Lead III potentials in step1515. In step1517, compensated lead values are determined using Equations 10 and 11. Even though Equations 10 and 11 compensate for two of the three leads, the third lead can be compensated in accordance with Equations 1A-1C. Steps1513-1517are repeated for subsequent ECG samples.

With another embodiment of the invention, the methods shown inFIGS. 14A,14B,15A, and15B can be combined so that both compensation for electrode positioning and signal noise can be performed on EEG signals received from a diagnostic garment.

The embodiments shown inFIGS. 14A,14B,15A, and15B exemplify compensating ECG samples from ECG electrodes that are positioned on a diagnostic garment. However, other embodiments of the invention support other algorithms to compensate for the ECG electrodes being positioned differently from the classical locations as shown inFIG. 1. Other embodiments of the invention may position ECG electrodes at different non-classical locations and correspondingly compensate for shifts in ECG electrode positioning.

FIG. 16shows an apparatus1600for obtaining, transforming, and communicating ECG measurements from electrodes that are positioned on a diagnostic garment in accordance with an embodiment of the invention. Measurement module1601obtains ECG inputs (samples)1651from ECG electrodes positioned on the diagnostic garment. In the embodiment, measurement module1601includes a buffer to appropriately interface to the voltage levels of the ECG electrodes and a multiplexer to interface with a plurality of ECG electrodes. Because ECG inputs typically have analog characteristics, analog to digital converter (ADC)1603converts analog ECG inputs into a digital format in order to process the ECG samples.

Processor1607may compensate the ECG samples (in accordance with processes1400and1500) or may transmit the uncompensated ECG samples to a remote apparatus (e.g., apparatus1700) over communications channel1653through communications module1605. The embodiment supports different types of communications channels including wireline channels (e.g., telephone, cable and Internet channels) and wireless channels (e.g., cellular radio channels, point-to-point radio channels, and infrared point-to-point channels).

FIG. 17shows an apparatus1700of a remote surveillance center for receiving and processing ECG measurements in accordance with an embodiment of the invention. In the embodiment apparatus1700receives uncompensated samples over communications channel1653through communications module1701. However, with another embodiment of the invention, apparatus1600may compensate ECG samples and send the compensated samples to apparatus1700.

Apparatus1700receives ECG samples, in which each ECG sample comprises ECG measurements from ECG electrodes positioned on a diagnostic garment. Demultiplexer1703separates the ECG measurements and passes them to processor1707through buffer1705. Processor1707processes the ECG samples. If the ECG samples are uncompensated, processor1707compensates the ECG samples in accordance with Equations 2-11.

The processed ECG samples may be stored in storage device1709for later retrieval or may be displayed on display module1711for a clinician to view. The clinician configures apparatus1700through input module1713for processing, storing, and displaying processed ECG samples.

As can be appreciated by one skilled in the art, a computer system with an associated computer-readable medium containing instructions for controlling the computer system can be utilized to implement the exemplary embodiments that are disclosed herein. The computer system may include at least one computer such as a microprocessor, digital signal processor, and associated peripheral electronic circuitry.

Disposable Diagnostic Garment Option

An embodiment of the invention provides a disposable version of the glove by making the glove out of a plastic material that can be inflated. By using an inflatable glove, the contour of the body (e.g., chest and torso) is automatically matched by the contour of the glove. The matching contours will allow for a close fit between the electrodes and the skin.

The inflation of the glove may be done automatically upon opening a package containing the glove by use of a one-way valve. The lower pressure within the glove will cause it to take in enough air to inflate the glove.

The electrode may be painted or printed on the plastic of the glove allowing for a low cost method of producing the glove.

The glove may be either two dimensional (i.e. a single seam) or three dimensional (i.e. multiple seams). The two dimensional reduces cost while the three dimensional version allows more flexibility in adapting the glove to the contour of the body.

FIGS. 18-21illustrate a version of an inflatable glove. The inflatable glove is in the form of a hollow rod1802having affixed thereto a preformed series of hollow, molded, elongate, flexible pillow members1804. The pillow members1804are separated one from the other by a seam such as seam1806but connected by a gas flow passage. ECG electrodes such as electrodes1830are provided on the various inflated pillow members1804. Electrodes1830are also positioned on opposite ends of the carrier rod or stick1802. As shown inFIG. 18, the separate electrodes1830may include leads or lead wires1832connected thereto. The electrodes1830are spaced by virtue of their positioning on the discrete pillow members1804to accommodate a desired physical positioning or spacing such as would be accomplished by the sleeve and glove depicted inFIG. 3.

A valve1834is provided in hollow rod or tube member to effect inflation of the pillow members1804of the glove. The opposite side of the glove including the rod1802as well as the pillow members1804, may include an appropriate adhesive for maintaining placement of the inflatable glove on the hand of an individual such as illustrated in phantom inFIG. 18.

The uninflated pillow member1804of the glove of the type depicted inFIG. 18may then be folded over the rod when it is originally packaged and upon unpackaging and inflation will assume the configuration such as shown inFIGS. 18-21. The glove may then be placed upon the hand and lower arm of an individual. The glove is typically placed upon the left hand and lower arm or forearm in the manner depicted for example with respect to the glove and sleeve ofFIGS. 3,4and5. The pillow members1804may then be inflated by inserting air or a non-toxic gas through the valve mechanism1834into the rod1802and connected pillow members1804.

The device is manufacturable in various sizes. Thus the number of pillow members or elements1804, the length of the rod1802, the size of the pillow elements1804and other dimensional characteristics of the disclosed glove may be altered in order to accommodate persons having different physiology. Additionally, the glove may be disposed following use. Further, the electrodes1830may be affixed to the various pillow segments1804by deposition of a conductive material on the inflatable plastic which is utilized to make the pillow. Likewise the leads1832may also be affixed by such deposition techniques and connected to a socket assembly1835mounted on the rod1802. Socket assembly1835may then receive a plug (not shown) which connects to a central control unit24.

Alternative aspects and features of the embodiment ofFIGS. 18-21include the capability of folding the uninflated pillow members around the rod or stick1802. Thus the assembly can then be conveniently packaged in a small box or sealed package for subsequent removal and inflation. The pillow members1804may be formed of heat sealed sheets of plastic material with an air flow channel provided between the pillow member1804. The conductive electrodes and leads may be printed on the surface of the preinflated pillow members1804are affixed or molded into the material forming the pillow members1804. The pillow members1804may have distinct sizes and shapes. The pillow members1804may also be sectioned so that only discrete portions thereof inflate. The rod1802is typically hollow but generally rigid to facilitate manual gripping and proper positioning.

While the invention has been described with respect to specific examples including multiple modes of carrying out the invention, those skilled in the art will appreciate that there are numerous variations and permutations of the above described systems and techniques that fall within the spirit and scope of the invention as set forth in the appended claims.