Patent Publication Number: US-2023149076-A1

Title: System and method for pericardial puncture

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation application of International Application No. PCT/162021/056368, filed Jul. 14, 2021, titled “SYSTEM AND METHOD FOR PERICARDIAL PUNCTURE,” which claims priority to U.S. Provisional Application No. 63/052,999, filed Jul. 17, 2020, titled “SYSTEM AND METHOD FOR PERICARDIAL PUNCTURE,” the entire disclosures of which are incorporated herein by reference. 
    
    
     FIELD 
     This document relates to methods for carrying out medical procedures. More specifically, this document relates to methods for pericardial puncture, and related systems. 
     SUMMARY 
     The following summary is intended to introduce the reader to various aspects of the detailed description, but not to define or delimit any invention. 
     Methods for pericardial puncture are disclosed. According to some aspects, a method for pericardial puncture includes: a. contacting a pericardium of a heart of a patient with an electrode of a medical device; and b. while the heart is in a contracted state, delivering radiofrequency energy from the electrode to puncture the pericardium. 
     The method can further include, prior to step b., delivering a stimulus signal to the heart to force contraction and transient standstill of the heart in the contracted state. 
     The stimulus signal can be delivered from a pulse generator to the electrode of the medical device. The radiofrequency energy can be delivered from a radiofrequency generator to the electrode. The delivery of radiofrequency energy from the radiofrequency generator can be automatic based on the delivery of the stimulus signal and can occur automatically following the delivery of the stimulus signal. The pulse generator can communicate with the radiofrequency generator to coordinate the delivery of the stimulus signal and the delivery of the radiofrequency energy. 
     In some examples, the stimulus signal is delivered from the electrode of the medical device. 
     In some examples, the stimulus signal is delivered from a secondary medical device. During delivery of the stimulus signal, the secondary medical device can be spaced from the heart. The method can further include, prior to step a., advancing the electrode towards the heart via an introducer, and the stimulus signal can be delivered from the introducer to the heart. 
     In some examples, step a. can include applying force to the heart with the electrode. Delivering a stimulus signal to the heart can cause the heart to move away from the electrode to reduce the amount of force applied to the heart with the electrode. 
     In some examples, the method further includes, prior to step b., using electrocardiography monitoring to determine when the heart is in the contracted state. 
     In some examples, the method further includes, prior to step b., using medical imaging to determine when the heart is in the contracted state. 
     Systems of medical devices are also disclosed. According to some aspects, a system of medical devices includes a pulse generator for delivering a stimulus signal, a radiofrequency (RF) generator for delivering RF energy, and a medical device. The medical device includes an elongate shaft and an electrode at a distal end of the shaft. The electrode is electrically connected to the pulse generator for receiving a stimulus signal from the pulse generator and delivering the stimulus signal to a heart to force contraction and transient standstill of the heart. The electrode is electrically connected to the RF generator for receiving RF energy from the RF generator and delivering the RF energy to a tissue of the heart to puncture the tissue. 
     In some examples, the RF generator is in communication with the pulse generator for coordination of the delivery of the stimulus signal and the RF energy. 
     In some examples, the elongate shaft includes a wire and a layer of electrical insulation on the wire. The electrode can include an electrically exposed end of the wire. The elongate shaft can be flexible or stiff. 
     In some examples, the system further includes an introducer through which the medical device is advanceable. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings are for illustrating examples of articles, methods, and apparatuses of the present disclosure and are not intended to be limiting. In the drawings: 
         FIG.  1    is a perspective view of a system for pericardial puncture; 
         FIG.  2    is a cross section taken along line  2 - 2  in  FIG.  1   ; 
         FIG.  3    is a schematic view showing a step of a method for pericardial puncture; 
         FIG.  4    is a schematic view showing a step subsequent to that of  FIG.  3   ; and 
         FIG.  5    is a schematic view showing a step subsequent to that of  FIG.  4   . 
     
    
    
     DETAILED DESCRIPTION 
     Various apparatuses or processes or compositions will be described below to provide an example of an embodiment of the claimed subject matter. No example described below limits any claim and any claim may cover processes or apparatuses or compositions that differ from those described below. The claims are not limited to apparatuses or processes or compositions having all of the features of any one apparatus or process or composition described below or to features common to multiple or all of the apparatuses or processes or compositions described below. It is possible that an apparatus or process or composition described below is not an embodiment of any exclusive right granted by issuance of this patent application. Any subject matter described below and for which an exclusive right is not granted by issuance of this patent application may be the subject matter of another protective instrument, for example, a continuing patent application, and the applicants, inventors or owners do not intend to abandon, disclaim or dedicate to the public any such subject matter by its disclosure in this document. 
     Generally disclosed herein is a method for pericardial puncture in which puncture occurs while the heart is in a contracted state (i.e. during systole). For example, a stimulus signal can be delivered to the heart to force contraction and transient standstill of the heart in the contracted state. Then, while the heart is in the contracted state, radiofrequency (RF) energy can be delivered to puncture the pericardium. Alternatively, ECG monitoring can be used to determine when the heart is naturally in a contracted state, and while the heart is naturally in the contracted state, radiofrequency (RF) energy can be delivered to puncture the pericardium. Puncturing the pericardium while the heart is in a contracted state can reduce the risk of puncturing deeper tissue within the heart (e.g. the myocardium) and can thus enhance patient safety. More specifically, when using an RF puncture device to puncture the pericardium, the force applied to the heart by the device will vary during beating of the heart. That is, during diastole, the heart will move towards the RF puncture device, increasing the force applied to the heart by the device. In contrast, during systole, the heart will move away from the RF puncture device, decreasing the force applied to the heart by the device. Because the heart moves away from the RF puncture device during systole and the force applied to the heart by the RF puncture device is decreased during systole, puncturing the pericardium during systole can minimize the depth to which the RF puncture device penetrates into the heart (as compared to puncturing during diastole). 
     Referring now to  FIG.  1   , an example system  100  of medical devices is shown. The system  100  generally includes a medical device  102  that can be used for both RF puncture and stimulus signal delivery, and that can also be used as a guidewire. More specifically, the medical device  102  includes an elongate shaft  104  having a proximal end  106  and a distal end  108 . An electrode  110  is at the distal end  108 . Referring to  FIG.  2   , in the example shown, the shaft  104  includes a wire  112  and a layer of electrical insulation  114  on the wire  112 , and the electrode  110  is in the form of an electrically exposed end of the wire  112 . The electrode  110  can deliver a stimulus signal to a tissue and deliver RF energy to puncture the tissue, as will be described below. 
     In the example shown, the shaft  104  is resiliently flexible. That is, the shaft  104  is biased towards a generally straight configuration, but can be curved or bent with the application of force. When force is removed, the shaft  104  will move back towards a straight configuration. 
     In alternative examples, the shaft can be relatively stiff (e.g. the shaft can be of a similar stiffness to a needle). 
     Referring back to  FIG.  1   , the system  100  further includes a pulse generator  116  and an RF generator  118 , and the electrode  110  is electrically connected to the pulse generator  116  and the RF generator  118  via the wire  112  (not shown in  FIG.  1   ). 
     The pulse generator  116  can generate a stimulus signal, and the electrode  110  can receive the stimulus signal and deliver the stimulus signal to a tissue with which the electrode  110  is in contact (e.g. the pericardium). When delivered to the heart, the stimulus signal can force contraction and transient standstill of the heart in a contracted state (e.g. the stimulus signal can be a rapid pacing signal). The pulse generator  116  can be, for example, one sold by GE Healthcare under the brand name Micropace. 
     The RF generator  118  can generate RF energy and the electrode  110  can receive the RF energy from the RF generator  118  and deliver the RF energy to the tissue with which the electrode  110  is in contact (e.g. the pericardium). When delivered to the tissue, the RF energy can cause puncture of the tissue. The RF generator  118  can be, for example, one sold by Baylis Medical Company Inc. (Montreal, Canada). The RF generator  118  can be connected to one or more grounding pads (not shown). 
     Referring still to  FIG.  1   , in the example shown, the medical device  102  is directly electrically connected to the RF generator  118  at the proximal end  106  of the shaft  104 , and the RF generator  118  is electrically connected to the pulse generator  116  by a cable  120 , so that the medical device  102  is indirectly electrically connected to the pulse generator  116  via the RF generator  118 . As will be described below, electrically connecting the RF generator  118  and the pulse generator  116  allows for communication between the RF generator  118  and the pulse generator  116 , so that delivery of the stimulus signal and the delivery of RF energy can be coordinated. In alternative examples, the medical device  102  can be directly electrically connected to both the RF generator  118  and the pulse generator  116 , or indirectly electrically connected to both the RF generator  118  and the pulse generator  116  (e.g. via an accessory device), or directly electrically connected to the pulse generator  116  and indirectly electrically connected to the RF generator  118  via the pulse generator  118 . 
     Referring now to  FIGS.  3  to  5   , a method of puncturing the pericardium will be described. The method will be described with reference to the system  100  and medical device  102  of  FIGS.  1  and  2   ; however, the method is not limited to the system  100  and/or the medical device  102 , and the system  100  and medical device  102  are not limited to operation according to the method. In  FIGS.  3  to  5   , the heart is generally shown at  300 , with the pericardium generally shown at  302 , the pericardial space generally shown at  304 , and the myocardium generally shown at  306 . 
     Referring first to  FIG.  3   , in use, the medical device  102  can be advanced towards a target location of the pericardium  302 . The medical device  102  can optionally be advanced towards the pericardium via an introducer  122 . For example, the introducer  122  can be percutaneously advanced towards the target location via the subxiphoid approach, with a stylet (not shown) received in the introducer  122 . The stylet can then be removed, and the medical device  102  can be advanced through the introducer  122  towards the target location, to contact the pericardium with the electrode  110 . In  FIG.  3   , the heart is shown in diastole, and the medical device  102  has been advanced slightly beyond the minimum distance needed to contact the pericardium  302  when the heart  300  is in diastole, so that contact with the pericardium  302  causes the shaft  104  to flex away from a straight configuration. Due to the resiliently flexible nature of the shaft  104  and the bias of the shaft  104  towards a straight configuration, when in the configuration shown in  FIG.  3   , the shaft  104  will apply force to the pericardium  302 . 
     Once the electrode  110  is in contact with the pericardium  302  and in the position shown in  FIG.  3   , a stimulus signal can be delivered from the pulse generator  116  (not shown in  FIGS.  3  to  5   ) to the electrode  110 , and from the electrode  110  to the heart  300 . The stimulus signal can be tuned so that it forces contraction and transient standstill of the heart  300  in a contracted state (i.e. in systole), as shown in  FIG.  4   . For example, the stimulus signal can be a rapid pacing signal. Due to the resiliently flexible nature of the shaft  104 , the shaft  104  will remain in contact with the heart  300  as the heart  300  contracts and the shaft  104  straightens slightly. However, due to the contraction of the heart  300 , the heart  300  will move away from the medical device  102  and the force applied to pericardium  302  by the medical device  102  when in the configuration shown in  FIG.  4    will be less than the force applied to pericardium  302  by the medical device  102  when in the configuration shown in  FIG.  3   . In  FIG.  4   , the former position of the pericardium  302  and the medical device  102  is shown in dotted line. 
     While the heart  300  and medical device  102  are in the configuration shown in  FIG.  4    (i.e. while the heart  300  is in the contracted state and while the electrode  110  is in contact with the heart  300 ), RF energy can be delivered from the RF generator  118  (not shown in  FIGS.  3  to  5   ) to the electrode  110 , and from the electrode  110  to the pericardium  302 , to puncture the pericardium  302 . As mentioned above, in order to ensure that RF energy is delivered while the heart  300  and medical device  102  are in the configuration shown in  FIG.  4   , the pulse generator  116  and the RF generator  118  are in communication, to coordinate delivery of the stimulus signal and delivery of the RF energy. For example, the delivery of RF energy can be automatic, based on the delivery of the stimulus signal. More specifically, the RF generator  118  can be configured to deliver RF energy automatically, either immediately following the delivery of the stimulus signal, or after a set time period has passed following the delivery of the stimulus signal, to ensure that RF energy is delivered only when the heart  300  is forced into transient standstill in the contracted state. Delivery of RF energy to the heart  300  when the heart  300  and the medical device  102  are in the configuration shown in  FIG.  4    can cause the electrode  110  to puncture the pericardium  302 , as shown in  FIG.  5   . Delivery of RF energy can be brief (e.g. lasting less than one second) and can be stopped as soon as puncture has occurred. Because puncture occurs when the heart  300  is in the contracted state, the medical device  102  penetrates only a small amount into the pericardial space  304 , and does not puncture or damage the myocardium  306 . 
     After the pericardium  302  has been punctured and after the delivery of RF energy has been stopped, the medical device  102  can be further advanced into the pericardial space  304 , and can be used as a guidewire in further steps of the medical procedure. 
     In the example described above, the pulse generator  116  is electrically connected to the medical device  102 , and the stimulus signal is delivered from the pulse generator to the electrode  110  and from the electrode  110  to the heart  300 . In alternative examples, a secondary medical device can be electrically connected to the pulse generator  116 , and the stimulus signal can be delivered from the secondary medical device to the heart  300 . Furthermore, the secondary medical device may be spaced from the heart  300  during delivery of the stimulus signal (i.e. the secondary medical device need not be in contact with the heart  300 ). For example, the introducer  122  can include a stimulus electrode and can be electrically connected to the pulse generator  116 , and the stimulus signal can be delivered from the stimulus electrode of the introducer  122  to the heart  300 . 
     In the example described above, in order to ensure or facilitate delivery of RF energy when the heart  300  is in the contracted state, the heart  300  is forced into the contracted state by delivery of a stimulus signal. In alternative examples, delivery of a stimulus signal can be omitted, and delivery of RF energy can be coordinated with the natural rhythm of the heart. For example, medical imaging (e.g. fluoroscopy, ultrasound, and/or echocardiography) and/or electrocardiography (ECG) monitoring can be used to determine when the heart  300  is in a contracted state and/or to predict when the heart  300  will be in a contracted state. In the case of ECG monitoring, the ECG monitoring can optionally be done via the medical device  102  - i.e. the electrode  110  can also serve as an ECG electrode, and can receive ECG signals from the heart  300  and deliver the ECG signals to an ECG monitoring system (not shown). The ECG monitoring system can optionally be in communication with the RF generator  118 , in order to coordinate delivery of RF energy with ECG monitoring, and delivery of RF energy can be automatic based on the ECG signals received from the heart  300 . More specifically, delivery of RF energy can optionally occur automatically when the ECG monitoring system determines that the heart  300  is contracted. For example, the ECG monitoring system can detect the beginning of the RR interval in the heart  300 , and the RF generator  118  can automatically deliver RF energy at the beginning of the RR interval (e.g. for up to 0.4 seconds, or for between 0.1 and 0.4 seconds). Alternatively, a user can read the ECG monitoring system to determine that the heart  300  is contracted, and manually initiate delivery of RF energy. 
     In examples wherein ECG monitoring is used to determine or predict when the heart  300  is in a contracted state, the ECG monitoring system can be configured to distinguish isovolumetric contraction, ejection, isovolumetric relaxation, rapid inflow, diastasis, and atrial systole. 
     While the above description provides examples of one or more processes or apparatuses or compositions, it will be appreciated that other processes or apparatuses or compositions may be within the scope of the accompanying claims. 
     To the extent any amendments, characterizations, or other assertions previously made (in this or in any related patent applications or patents, including any parent, sibling, or child) with respect to any art, prior or otherwise, could be construed as a disclaimer of any subject matter supported by the present disclosure of this application, Applicant hereby rescinds and retracts such disclaimer. Applicant also respectfully submits that any prior art previously considered in any related patent applications or patents, including any parent, sibling, or child, may need to be re-visited.