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Implanted Pacemaker (implanted + pacemaker)

Distribution by Scientific Domains

Medical Sciences	77%

Selected Abstracts

Influence of Mobile Magnetic Resonance Imaging on Implanted Pacemakers

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1p2 2003
RYOJI KISHI
KISHI, R., et al.: Influence of Mobile Magnetic Resonance Imaging on Implanted Pacemakers.Purpose: Mobile magnetic resonance imaging (MRI) systems will be widely used in Japan. When traveling, mobile MRI generate alternating electromagnetic waves which may cause electromagnetic interference (EMI). This study was designed to determine whether this may influence the function of implanted pacemakers (PM). Methods and Results: The influence of the static magnetic fields was tested in the first method using a PM-human model (Phantom). Magnetic force was simultaneously measured. The PM was switched to the magnet mode within 90 cm from the vehicle, where the magnetic force was = 2 mT. In the second method, six phantoms were placed on the side of the road, facing in three different directions in X-Y-Z axis orientations, at 1.3 m and 2.0 m above the ground. The mobile MRI passed by at a distance of 1 m from the phantoms at the speed of 20 or 40 km/h. In these experiments, magnet mode switch of the PM was observed for 2 seconds when the vehicle passed close to the phantoms, though no electrical noise was recorded. Conclusion: Mobile MRI vehicles can switch a PM to magnet mode when the distance between patient and vehicle is <90 cm, regardless of whether the vehicle is moving or at a stop. Patients with implanted PM should not approach within <1 m of a mobile MRI. No other EMI-induced PM dysfunction was detected. (PACE 2003; 26[Pt. II]:527,529) [source]

Presence and Duration of Atrial Fibrillation Detected by Continuous Monitoring: Crucial Implications for the Risk of Thromboembolic Events

JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2009
GIOVANNI L. BOTTO M.D.
Introduction: Asymptomatic atrial fibrillation (AF) can expose patients to the risk of stroke. The primary objective of this study was to assess the incidence of thromboembolic events in relationship with CHADS2 (congestive heart failure, hypertension, age ,75 years, diabetes mellitus, and prior stroke, or transient ischemic attack) score and AF presence/duration. The secondary objective was to compare intermittent versus continuous monitoring strategies. Methods and Results: Data from patients with an implanted pacemaker and a history of AF were analyzed. Thromboembolic risk was quantified through CHADS2 score. Three AF groups were considered: patients with <5-minutes AF on 1 day (AF-free); patients with >5-minutes AF on 1 day but <24 hours (AF-5 minutes); patients with AF episodes >24 hours (AF-24 hours). Monitoring strategies involving 24-hour Holter, 1-week Holter, and 30-day Holter were simulated. Data from 568 patients continuously monitored for 1 year were analyzed: 171 (30%) had CHADS2 score = 0; 269 (47%) had CHADS2 score = 1; 111 (20%) had CHADS2 score = 2; and 17 (3%) had CHADS2 score , 3. During follow-up, 14 patients (2.5%) had an ischemic thromboembolic event. AF-24 hours patients numbered 223 (39.2%); AF-5 minutes, 179 (31.5%); and AF-free, 29.2%. By combining AF presence/duration with CHADS2 score, two subpopulations with markedly different risks of events (0.8% vs 5%, P = 0.035) were identified, the former corresponding to AF-free with CHADS2,2, or AF-5 minutes with CHADS2,1, or AF-24 hours with CHADS2= 0. The mean sensitivity in detecting an AF episode lasting >5 minutes was 44.4%, 50.4%, and 65.1% for 24-hour Holter, 1-week Holter, and 1-month Holter monitoring, respectively. Conclusion: In patients with recurrent AF episodes, risk stratification for thromboembolic events can be improved by combining CHADS2 score with AF presence/duration. [source]

Performance of an Autonomous Telemonitoring System in Children and Young Adults with Congenital Heart Diseases

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2008
PETER ZARTNER M.D.
Background:Integrated telemonitoring systems controlling circulatory and electrical parameters in adults with an implanted pacemaker have shown to be advantageous during follow-up of this patient group. In children and young adults with a congenital heart disease (CHD), these systems have to cope with a diversity of varying arrhythmias and a broad range of intrinsic cardiac parameters. Additional problems arise from the patients' growth and anatomic anomalies. Methods:Since 2005, eight young patients (age 4.1, 37 years, mean 15.5 years) with a CHD received a pacemaker or implantable cardioverter defibrillator with an autonomous telemonitoring system at our clinic. The mean follow-up time was 395 days (range 106,834 days, 8.7 patient years). Results:In seven of eight patients the system transmitted information, which led to beneficial modifications of the current antiarrhythmic therapy. In three patients the reported events were of a critical nature. One patient remained event-free for 192 days after implantation. During follow-up, 96% of the days were covered. The system also transferred additional information on the effectiveness of antiarrhythmic medication and the impact of physical activity. Conclusions:Young patients with an insufficient intrinsic heart rate or progressing arrhythmia, in addition to the conventional indications for pacemaker or defibrillator implantation, seem to profit to a high percentage from a telemetric surveillance system. The fully automated procedure of device interrogation and information transmission gives a daily overview on system function and specific arrhythmic events, especially in children who are unaware of any symptoms. [source]

Programming Optimal Atrioventricular Delay in Dual Chamber Pacing Using Peak Endocardial Acceleration: Comparison with a Standard Echocardiographic Procedure

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1p2 2003
JEAN-MARC DUPUIS
DUPUIS, J.-M.,et al.: Programming Optimal Atrioventricular Delay in Dual Chamber Pacing Using Peak Endocardial Acceleration: Comparison with a Standard Echocardiographic Procedure.Optimization of programmed atrioventricular delay in dual chamber pacing is essential to the hemodynamic efficiency of the heart. Automatic AV delay optimization in an implanted pacemaker is highly desirable. Variations of peak endocardial acceleration (PEA) with AV delay at rest correlate well with echocardiography derived observations, particularly with end-diastolic filling and mitral valve closure timings. This suggests the possibility of devising a procedure for the automatic determination of the optimal AV delay. The aim of this study was to compare a proposed algorithm for optimal AV delay determination with an accepted echocardiographic method. Fifteen patients with high degree AV block received BEST-Living pacing systems. Automatic AV delay scans were performed at rest (60,300 ms in 20-ms steps with 60 beats per step) in DDD at 90 ppm, while simultaneously recording cycle-by-cycle PEA values, which were averaged for each AV delay to obtain a PEA versus AV delay curve. Nonlinear regression analysis based on a Boltzmann sigmoid curve was performed, and the optimal AV delay (OAVD) was chosen as the sigmoid inflection point of the regression curve. The OAVD was also evaluated for each patient using the Ritter echocardiographic method. Good sigmoid fit was obtained in 13 of 15 patients. The mean OAVD obtained by the PEA sigmoid algorithm was146.9 ± 32.1 ms, and the corresponding result obtained by echocardiography was156.4 ± 34.3 ms(range 31.8,39.7 ms). Correlation analysis yielded r = 0.79, P = 0.0012. In conclusion, OAVD estimates obtained by PEA analysis during automatic AV delay scanning are consistent with those obtained by echocardiography. The proposed algorithm can be used for automatic OAVD determination in an implanted pacemaker pulse generator. (PACE 2003; 26:[Pt. II]:210,213) [source]

A Petri Net Approach to Remote Diagnosis for Failures of Cardiac Pacemakers

QUALITY AND RELIABILITY ENGINEERING INTERNATIONAL, Issue 8 2004
S. K. Yang
Abstract This paper describes the application of Petri nets to remote diagnosis for failures of cardiac pacemakers. The operations, structures and basic control methods of the different types of cardiac pacemakers are first described. A combined synchronous pacemaker is modeled into a Petri net in this study. Twelve checkpoints are added into the modeled Petri net so as to construct a Petri net for failure diagnosis. A remote mode for failure diagnosis of implanted pacemakers is also designed by the Petri net approach. A low-power transmitter transmits a checking-code with 12 digits from the implanted pacemaker to the outside of the patient's body manually or automatically. By observing the markings of the checking code, the working status and the health condition of the pacemaker are clear at a glance. Applications of the Petri net method for failure diagnosis and control optimization are discussed. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Influence of Mobile Magnetic Resonance Imaging on Implanted Pacemakers

Safety of Pacemaker Implantation Prior to Radiofrequency Ablation of Atrioventricular Junction in a Single Session Procedure

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 6 2000
ALESSANDRO PROCLEMER
RF current delivery may cause acute and chronic dysfunction of previously implanted pacemakers. The aim of this study was to assess prospectively the effects of RF energy on Thera I and Kappa pacemakers in 70 consecutive patients (mean age 70 ± 11 years, mean left ventricular ejection fraction 48 ± 15%) who underwent RF ablation of the AV junction for antiarrhythmic drug refractory atrial fibrillation (permanent in 42 patients, paroxysmal in 28). These pacing systems incorporate protection elements to avoid electromagnetic interference. The pacemakers (Thera DR 7960 I in 20 patients, Thera SR 8960 1 in 30, Kappa DR 600,601 in 8, Kappa SR 700,701 in 12) were implanted prior to RF ablation in a single session procedure and were transiently programmed to VVI mode at a rate of 30 beats/min. Capsure SP and Z unibipolar leads were used. During RF application there was continuous monitoring of three ECG leads, endocavitary electrograms, and event markers. Complete AV block was achieved in all cases after 3.6 ± 2.9 RF pulses and 100 ± 75 seconds of RF energy delivery. The mean time of pacemaker implantation and RF ablation was 60 ± 20 minutes. Transient or permanent pacemaker dysfunction including under/oversensing, reversion to a "noise-mode" pacing, pacing inhibition, reprogramming, or recycling were not observed. Leads impedance, sensing, and pacing thresholds remained in the normal range in the acute and long-term phase (average follow-up 18 ± 12 months). In conclusion, Thera I and Kappa pacemakers exhibit excellent protection against interference produced by RF current. The functional integrity of the pacemakers and Capsure leads was observed in the acute and chronic phases. Thus, the implantation of these pacing systems prior to RF ablation of the AV junction can be recommended. [source]

Successful Treatment of Severe Orthostatic Hypotension with Cardiac Tachypacing in Dual Chamber Pacemakers

PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2000
HARUHIKO ABE
Orthostatic hypotension is an evolving and disabling disease usually observed in elderly patients with dramatic consequences on morbidity, mortality, and impairing the quality of life. We studied the effects of the pacing rate and AV interval on the blood pressure drop in the upright position in two patients with previously implanted pacemakers for sinus node dysfunction. Although the AV interval did not affect the blood pressure drop in the upright position, tachypacing at 100 paces/min improved it dramatically and prevented syncope. Cardiac tachypacing is a useful therapeutic option in severe refractory Orthostatic hypotensive patients, especially those with chronotropic incompetence. [source]