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Bipolar Lead (bipolar + lead)
Selected AbstractsUnexpected Loss of Bipolar Pacing With Implanted Dual Chamber PacemakersPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2000G. BIH-FANG GUO Bipolar leads are most commonly used in the current practice of pacemaker therapy. In our study of 124 patients implanted with Guidant/Cardiac Pacemakers (CPI) Vigor dual chamber pacemakers, 5 patients had unexpectedly abrupt increases in bipolar lead impedance and pacing threshold 2 weeks to 18 months postimplantation without changes in sensing function. With the lead configuration reprogrammed to unipolar, the lead impedance and pacing threshold were restored to appropriate ranges. The changes in bipolar lead parameters can be caused by the CPI's "Quick Connect" (QC1) header lead system incorporated in these pacemakers. [source] Synchronous Ventricular Pacing without Crossing the Tricuspid Valve or Entering the Coronary Sinus,Preliminary ResultsJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 12 2009BENHUR D. HENZ M.D. Background: Right ventricular apical (RVA) pacing promotes tricuspid regurgitation (TR), electromechanical dyssynchrony, and ventricular dysfunction. We tested a novel intramyocardial bipolar lead to assess whether stimulation of the atrioventricular septum (AVS) produces synchronous ventricular activation without crossing the tricuspid valve (TV). Methods: A lead with an active external helix and central pin was placed on the AVS and the RVA in three dogs. High-density electroanatomic (EA) mapping was performed of both ventricles endocardially and epicardially. Intracardiac echocardiography was used to access ventricular synchrony. Results: The lead was successfully deployed into the AVS in all cases with consistent capture of the ventricular myocardium without atrial capture or sensing. The QRS duration was less with AVS compared with RVA pacing (89 ± 4 ms vs. 100 ± 11 ms [P < 0.0001, GEE P = 0.03]). There was decreased delay between color Doppler M-mode visualized peak contraction of the septum and the mid left ventricular free wall with AVS compared with RVA pacing (89 ± 91 ms vs. 250 ± 11 ms [P < 0.0001, GEE P = 0.006]). Activation time between the mid septum and mid free wall was shorter with AVS versus RVA pacing (20.4 ± 7.7 vs. 30.8 ± 11.6 [P = 0.01, GEE P = 0.07]). The interval between QRS onset to earliest free wall activation was shorter with AVS vs. RVA pacing (19.2 ± 6.4 ms vs. 31.1 ± 11.7 ms [P = 0.005, GEE P = 0.02]). Conclusion: The AVS was successfully paced in three dogs resulting in synchronous ventricular activation without crossing the TV. [source] Innovative Techniques for Placement of Implantable Cardioverter-Defibrillator Leads in Patients with Limited Venous Access to the HeartPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2006BRYAN C. CANNON Background: Because of venous occlusion, intracardiac shunting, previous surgery, or small size placement of implantable cardioverter-defibrillator (ICD) leads may not be possible using traditional methods. The purpose of this study was to evaluate and describe innovative methods of placing ICD leads. Methods: The records of all patients undergoing ICD implantation at our institution were reviewed to identify patients with nontraditional lead placement. Indications for ICD, method of lead and coil placement, defibrillation thresholds, complications, and follow-up results were reviewed retrospectively. Results: Eight patients (aged 11 months to 29 years) were identified. Six patients with limited venous access to the heart (four extracardiac Fontan, one bidirectional Glenn, one 8 kg 11-month-old) underwent surgical placement of an ICD coil directly into the pericardial sac. A second bipolar lead was placed on the ventricle for sensing and pacing. Two patients with difficult venous access had a standard transvenous ICD lead inserted directly into the right atrium (transatrial approach) and then positioned into the ventricle. All patients had a defibrillation threshold of <20 J, although one patient required placement of a second coil due to an elevated threshold. There have been no complications and two successful appropriate ICD discharges at follow-up (median 22 months, range 5,42 months). Conclusions: Many factors may prohibit transvenous ICD lead placement. Nontraditional surgical placement of subcutaneous ICD leads on the pericardium or the use of a transatrial approach can be effective techniques in these patients. These procedures can be performed at low risk to the patient with excellent defibrillation thresholds. [source] Initial Experience with an Active-Fixation Defibrillation Electrode and the Presence of Nonphysiological SensingPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2001RAHUL N. DOSHI DOSHI, R.N., et al.: Initial Experience with an Active-Fixation Defibrillation Electrode and the Presence of Nonphysiological Sensing. Nonphysiological sensing by a pacing and defibrillation electrode may result in inappropriate defibrillator discharges and/or inhibition of pacing. Active-fixation electrodes may be more likely to sense diaphragmatic myopotentials because of the protrusion of the screw for fixation. In addition, the movement of the fixation screw in an integrated bipolar lead system could also result in inappropriate sensing. This may be increasingly important in patients who are pacemaker dependent because the dynamic range of the autogain feature of these devices is much more narrow. Five of 15 consecutive patients who received a CPI model 0154 or 0155 active-fixation defibrillation electrode with an ICD system (CPI Ventak AV3DR model 1831 or CPI Ventak VR model 1774 defibrillator) are described. In 2 of the 15 patients, nonphysiological sensing appearing to be diaphragmatic myopotentials resulted in inappropriate defibrillator discharges. Both patients were pacemaker dependent. Changes in the sensitivity from nominal to less sensitive prevented inappropriate discharges. In one patient, discreet nonphysiological sensed events with the electrogram suggestive of ventricular activation was noted at the time of implantation. This was completely eliminated by redeployment of the active-fixation lead in the interventricular septum. In two other patients, discreet nonphysiological sensed events resulted in intermittent inhibition of ventricular pacing after implantation. These were still seen in the least sensitive autogain mode for ventricular amplitude. These were not seen on subsequent interrogation 1 month after implantation. Increased awareness of nonphysiological sensing is recommended. The CPI 0154 and 0155 leads seem to be particularly prone to this abnormality. Particular attention should be made when deploying an active-fixation screw for an integrated bipolar lead. This increased awareness is more important when a given individual is pacemaker dependent, which may warrant DFT testing in a least or less sensitive mode in these patients. [source] Atrial Evoked Response Integral for Automatic Capture Verification in Atrial PacingPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1p2 2003GIUSEPPE BORIANI BORIANI, G.,et al.:Atrial Evoked Response Integral for Automatic Capture Verification in Atrial Pacing. Beat-by-beat Autocapture is currently limited to operation in the ventricle with bipolar leads. The authors investigated the integral of the negative-going portion of the atrial evoked response integral (AERI) as a potential resource for verification of atrial capture. Intracardiac electrogram signals were collected from 59 patients (ages 67.8 ± 15.1 years) with bipolar, low polarization atrial leads. The signals were collected over a mean period of 6.1 months (minimum 4 days) after lead implantation. St. Jude Medical Affinity pulse generators were used to perform automatic capture threshold tests while the electrogram signals were recorded by a Model 3510 programming device. These signals were transferred to a personal computer in digital form for later analysis. The AERI was calculated at each programmable pacing voltage until capture was lost. The difference between the polarization integral at loss of capture and evoked response integral with successful capture was sufficient to justify enabling the atrial Autocapture feature in 53 of 59 patients in whom bipolar pacing and unipolar sensing was performed. The authors developed a calibration routine to identify automatically those patients in whom atrial Autocapture could be programmed On, based on the polarization integral at loss of capture, the estimated maximum polarization integral, and the AERI. Preliminary analysis indicated that the AERI is a practical resource for beat-by-beat atrial capture detection when used with low polarization leads. (PACE 2003; 26[Pt. II]:248,252) [source] Transient Exit Block of a DDD Pacemaker with Unipolar Leads in Subcutaneous Emphysema Following PneumothoraxPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 5 2001CHRÍSTOPHE MELZER MELZER, C., et al.: Transient Exit Block of a DDD Pacemaker with Unipolar Leads in Subcutaneous Emphysema Following Pneumothorax. This case report describes a transient pacemaker exit block due to subcutaneous emphysema following pneumothorax. Pneumothorax after pacemaker implantation is rare, but development of subcutaneous emphysema under such circumstances is even more uncommon. Exit block develops only with the use of unipolar leads; with implantation of bipolar leads, this complication cannot occur. [source] Improved Differentiation of the Ventricular Evoked Response from Polarization by Modification of the Pacemaker ImpulsePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 12 2000FRANK PROVENIER The Autocapture feature, implemented in the Microny and Regency pacemakers of St. Jude Medical, continuously controls the effectiveness of ventricular stimulation by detection of the evoked response. Proper sensing of this signal depends on the magnitude of the polarization, which should be minimal. Therefore, the conjunctive use of low polarization electrodes is recommended. Further, the pacing impulse of these pacemakers has a biphasic waveform consisting of a stimulus followed by a fast discharge pulse. This study compares polarization of a modified pacing impulse with the default pacing impulse, and its effect on the ability to activate the Autocapture function when used with different types of electrodes. In 45 patients, acute measurements of the polarization and the evoked response were performed at random on the modified pacing impulses of a custom designed Regency and on the default stimuli of a standard Regency. The following bipolar leads were used: 20 Medtronic 4024 CapSure, 12 Pacesetter 1450T. and 13 Pacesetter 14701. Using the default pacing impulse, polarization and evoked response were significantly larger with the Medtronic 4024 CapSure compared to the low polarization leads. The polarization to evoked response ratio was more frequently acceptable for activation of the Autocapture with the Pacesetter leads. In all leads the modified pacing impulse was characterized bv significantly smaller polarization with the most prominent reduction in the Medtronic 4024 CapSure. The differences in the pacing impulse did not affect the evoked response. With the programmability of the fast discharge pulse, the requirements to activate the Autocapture function were fulfilled in 29 (94%) of 31 patients with the modified pacing impulse, compared to 22 (71%) of 31 patients with the standard pacing impulse. The modified pacing impulse decreased the "polarization to evoked response" ratio, and by that improved the conditions for activation of the Autocapture function. [source] | ||||||||||