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Chamber Pacemakers (chamber + pacemaker)
Kinds of Chamber Pacemakers Selected AbstractsTreatment of Inappropriate Sinus Tachycardia with Ivabradine in a Patient with Postural Orthostatic Tachycardia Syndrome and a Dual Chamber PacemakerPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2009SITARA KHAN M.R.C.P. We present the case of a 44-year-old woman with postural orthostatic tachycardia syndrome (POTS) and a dual chamber pacemaker. The patient suffered from inappropriate sinus tachycardia that had been resistant to treatment with traditional rate-slowing medications. Ivabradine,the specific sinus node If current inhibitor,was used to successfully lower the heart rate. The patient had no evidence of POTS on repeat autonomic function testing, and there was a corresponding symptomatic benefit. We propose that this class of drugs, the use of which is established as antianginals, should be considered in patients with resistant inappropriate sinus tachycardia. [source] Impact of Fusion Avoidance on Performance of the Automatic Threshold Tracking Feature in Dual Chamber Pacemakers: A Multicenter Prospective Randomized StudyPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 11 2002RETO CANDINAS CANDINAS, R., et al.: Impact of Fusion Avoidance on Performance of the Automatic Threshold Tracking Feature in Dual Chamber Pacemakers: A Multicenter Prospective Randomized Study. The Autocapture algorithm enables automatic capture verification on a beat-by-beat basis by recognizing the evoked response signal following each pacemaker stimulus. The algorithm intends to increase patient safety while decreasing energy consumption. However, the occurrence of fusion beats, particularly during dual chamber pacing, may limit the energy saving effect of Autocapture. The aim of this multicenter, prospective, randomized study was to evaluate the impact of the Fusion Avoidance (FA) algorithm on the incidence of fusion beats. Thirty-eight patients (mean age 69 ± 13 years) with intrinsic AV conduction who were implanted with an Affinity DR were studied. After programming a PV/AV delay of 120/190 ms, patients were randomized to FA On or Off. Each group was further randomized with respect to activation of the AutoIntrinsic Conduction Search (AICS) algorithm. The total number of beats, ventricular paced beats, fusion beats, backup pulses, and threshold searches were analyzed from 24-hour Holter recordings. The number of total beats was comparable in both FA groups. The number of total ventricular paced beats, fusion beats, backup pulses, and threshold searches were significantly reduced in the FA On group (% reduction: 68% P < 0.001, 75% P < 0.01, 95% P < 0.01, and 94% P < 0.05, respectively). The number of ventricular paced beats with full capture was significantly reduced when AICS was activated (P < 0.05). In conclusion, the FA algorithm substantially reduces the amount of ventricular paced beats, fusion beats, unnecessary backup pulses and threshold searches, and therefore, provides added benefits in energy saving obtained by Autocapture. [source] Unexpected 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] Successful Treatment of Severe Orthostatic Hypotension with Cardiac Tachypacing in Dual Chamber PacemakersPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2000HARUHIKO 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] Pacing in Right Ventricular Dysplasia after Disconnection SurgeryJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2000CHUEN TANG M.B.B.S. Pacing in Right Ventricular Dysplasia. This report describes a 33-year-old patient with arrhythmogenic right ventricular (RV) dysplasia who had a dual chamber pacemaker implanted at age 23 years for drug-induced bradycardia. Pacing was continued after right ventricular free-wall disconnection (RVFVVD) at age 24 years. Her pacemaker was not replaced after battery depletion 7 years later. She presented the following year in severe right-sided heart failure. Her old pacemaker generator was replaced. This was followed by rapid resolution of her clinical failure and return to a full, active, physical lifestyle. This observation suggests the potential benefit of dual chamber pacing in patients with RV dysplasia after RVFWD. [source] Treatment of Inappropriate Sinus Tachycardia with Ivabradine in a Patient with Postural Orthostatic Tachycardia Syndrome and a Dual Chamber PacemakerPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2009SITARA KHAN M.R.C.P. We present the case of a 44-year-old woman with postural orthostatic tachycardia syndrome (POTS) and a dual chamber pacemaker. The patient suffered from inappropriate sinus tachycardia that had been resistant to treatment with traditional rate-slowing medications. Ivabradine,the specific sinus node If current inhibitor,was used to successfully lower the heart rate. The patient had no evidence of POTS on repeat autonomic function testing, and there was a corresponding symptomatic benefit. We propose that this class of drugs, the use of which is established as antianginals, should be considered in patients with resistant inappropriate sinus tachycardia. [source] Inadvertent Positioning of Pacemaker Leads in the PericardiumPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 10 2003KAMBEEZ BERENJI A patient had a dual chamber pacemaker with endocardial leads implanted chronically. The lead position on chest X ray and the ECG pattern indicated lead malposition, but a CT scan and transesophageal echocardiography were nondiagnostic. Venography indicated that both leads were in the mediastinal and pericardial space. (PACE 2003; 26:2039,2041) [source] Runaway Pulse Generator Malfunction Resulting from Undetected Battery DepletionPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2 2002PUGAZHENDHI VIJAYARAMAN VIJAYARAMAN, P., et al.: Runaway Pulse Generator Malfunction Resulting from Undetected Battery Depletion. Runaway pacemaker is an uncommon, potentially lethal circuit malfunction characterized by sudden onset of erratic pacing at rapid nonphysiological rates. Two patients with a single chamber pacemaker (Medtronic ST 8331 and 8419) presented with episodic dizziness. ECG revealed recurrent decrescendo amplitude episodes of runaway stimuli at 2,400 and 2,600 ppm, approximately 3 seconds in duration, separated by pacing at 62.5 and 65 ppm, respectively. Fortunately the runaway stimuli were subthreshold and did not result in capture of the ventricle. Emergency pulse generator replacement was uneventful. Both leads were normal and both pulse generators had low battery voltages at 1.488 and 1.78 V, respectively. [source] Biventricular Pacing Using Two Pacemakers and the Triggered VVT ModePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 8 2001BRENDAN O'COCHLAIN O'COCHLAIN, B., et al.: Biventricular Pacing Using Two Pacemakers and the Triggered VVT Mode. Pacemaker dependent patients exhibit interventricular conduction delay due to right ventricular lead placement. The addition of a transvenous coronary sinus lead for biventricular pacing has been shown to be effective. Venous stenosis and thrombosis postpacemaker implantation can occur in up to 35% of patients. This report describes a patient with a preexisting left-sided dual chamber pacemaker and chronic left subclavian vein occlusion that was upgraded to a biventricular system by placing a coronary sinus lead and single chamber ventricular triggered pacemaker on the opposite side. [source] Relationship between Amplitude and Timing of Heart Sounds and Endocardial AccelerationPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 2009AUDE TASSIN M.D. Objective: To study the correlation between heart sounds and peak endocardial acceleration (PEA) amplitudes and timings, by modulation of paced atrioventricular (AV) delay in recipients of dual chamber pacemakers. Methods: Ten recipients of dual chamber pacemakers implanted for high-degree AV block were studied. Endocardial acceleration (EA) and phonocardiographic and electrocardiographic signals were recorded during performance of an AV delay scan in VDD and DDD modes. Results: First PEA (PEA I) and first heart sound (S1) changed similarly with the AV delay. A close intrapatient correlation was observed between S1 and PEA I amplitudes in all patients (P < 0.0001). The interpatient normalized PEA I to S1 amplitudes correlation was r = 0.89 (P < 0.0001) in DDD mode, and r = 0.81 (P < 0.0001) in VDD mode. The mean cycle-by-cycle PEA I to S1 delay was ,4.3 ± 22 ms and second PEA (PEA II) to second heart sound (S2) delay was ,7.7 ± 15 ms. Conclusions: A close correlation was observed between PEA I and S1 amplitudes and timings, and between PEA II and S2 timings. These observations support the hypothesis that PEA and heart sounds are manifestations of the same phenomena. EA might be a useful tool to monitor cardiac function. [source] Effect of Right Ventricular Apex Pacing on the Tei Index and Brain Natriuretic Peptide in Patients with a Dual-Chamber PacemakerPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 9 2006HITOSHI ICHIKI Background: Asynchronous electrical activation induced by right ventricular apex (RVA) pacing can cause various abnormalities in left ventricular (LV) function, particularly in the context of severe LV dysfunction or structural heart disease. However, the effect of RVA pacing in patients with normal LV and right ventricular (RV) function has not been fully elucidated. The aim of this study was to characterize the effects of RVA pacing on LV and RV function by assessing isovolumic contraction time and isovolumic relaxation time divided by ejection time (Tei index) and by assessing changes in plasma brain natriuretic peptide (BNP). Methods: Doppler echocardiographic study and BNP measurements were performed at follow-up (mean intervals from pacemaker implantation, 44 ± 75 months) in 76 patients with dual chamber pacemakers (sick sinus syndrome, n = 30; atrioventricular block, n = 46) without structural heart disease. Patients were classified based on frequency of RVA pacing, as determined by 24-hour ambulatory electrocardiogram (ECG) that was recorded just before echocardiographic study: pacing group, n = 46 patients with RVA pacing ,50% of the time, percentage of ventricular paced 100 ± 2%; sensing group, n = 30, patients with RVA pacing <50% of the time, percentage of ventricular paced 3 ± 6%. Results: There was no significant difference in mean heart rate derived from 24-hour ambulatory ECG recordings when comparing the two groups (66 ± 11 bpm vs 69 ± 8 bpm). LV Tei index was significantly higher in pacing group than in sensing group (0.67 ± 0.17 vs 0.45 ± 0.09, P < 0.0001), and the RV Tei index was significantly higher in pacing group than in sensing group (0.34 ± 0.19 vs 0.25 ± 0.09, P = 0.011). Furthermore, BNP levels were significantly higher in pacing group than in sensing group (40 ± 47 pg/mL vs 18 ± 11 pg/mL, P = 0.017). With the exception of LV diastolic dimension (49 ± 5 mm vs 45 ± 5 mm, P = 0.012), there were no significant differences in other echocardiographic parameters, including left atrium (LA) diameter (35 ± 8 mm vs 34 ±5 mm), LA volume (51 ± 27 cm3 vs 40 ± 21 cm3), LV systolic dimension (30 ± 6 mm vs 29 ± 7 mm), or ejection fraction (66 ± 9% vs 63 ± 11%), when comparing the two groups. Conclusions: These findings suggest that the increase of LV and RV Tei index, LVDd, and BNP are highly correlated with the frequency of the RVA pacing in patients with dual chamber pacemakers. [source] Automatic Mode Switching of Implantable Pacemakers: I. Principles of Instrumentation, Clinical, and Hemodynamic ConsiderationsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 6 2002CHU-PAK LAU LAU, C.-P., et al.: Automatic Mode Switching of Implantable Pacemakers: I. Principles of Instrumentation, Clinical, and Hemodynamic Considerations. Automatic mode switching (AMS) is now a programmable function in most contemporary dual chamber pacemakers. Atrial tachyarrhythmias are detected when the sensed atrial rate exceeds a "rate-cutoff,""running average,""sensor-based physiological" rate, or using "complex" detection algorithms. AMS algorithms differ in their atrial tachyarrhythmia detection method, sensitivity, and specificity and, thus, respond differently to atrial tachyarrhythmia in terms of speed to the AMS onset, rate stability of the response, and speed to resynchronize to sinus rhythm. AMS is hemodynamically beneficial, and most patients with atrial tachyarrhythmias are symptomatically better with an AMS algorithm in their pacemakers. New diagnostic capabilities of pacemaker especially stored electrograms not only allow programming of the AMS function, but enable quantification of atrial fibrillation burden that facilitate clinical management of patients with implantable devices who have concomitant atrial tachyarrhythmia. [source] Permanent Pacemaker Therapy Before and After the Reunification of Germany: 16 Years of Experience at an East German Regional Pacing CenterPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 6 2000P. KARNATZ The reunification of Germany had a significant influence on the management of patients with bradyarrhythmias. The current study was performed in a regional pacing center heated in the former German Democratic Republic. It compares the situation of patients with critical bradyarrhythmias before and after the reunification of Germany in 1990 focusing on (1) indication for pacemaker implantation. (2) pacemaker modalities and function, (3) type of leads, (4) frequency of reintervention, and (5) early and late complications. The study covers 9 years before and 7 years after the reunification. A total of 1,125 patients were included, and the database was formed by the patients' files and the protocols of implantation. The situation before reunification was characterized by a nonavailability of modern physiological pacing devices and insufficient diagnostic equipment. Between 1981 and 1990, 384 patients underwent pacemaker implantation solely receiving single chamber devices with no or only minimal feasibility of programming. Between 1990 and 1996, 741 patients were treated, and they all received modern pacemakers having the capability of multiprogramming and telemetry. Regarding complications of pacemaker therapy, lead related problems significantly decreased after the reunification (dislocation, 5.3% vs 1.7%, P < 0.05; exit block, 6.7% vs 1.4%. P < 0.05) opposite to pacemaker infections, which significantly increasing after dual chamber pacemakers were implanted (2.2% vs 6.0%, P < 0.05). The reunification of Germany dramatically improved the situation of patients with critical bradyarrhythmias leading to free access to high-tech pacing equipment within a few months. However, the abrupt change from antiquated to modern pacemaker therapy created some new problems, especially regarding application and handling of modern physiological pacing devices. [source] Unexpected 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] Preserving Normal Ventricular Activation Versus Atrioventricular Delay Optimization During Pacing: The Role of Intrinsic Atrioventricular Conduction and Pacing RatePACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 1 2000IVAN ILIEV ILIEV The purpose of the study was to compare the effects of DDD pacing with optimal AV delay and AAI pacing on the systolic and diastolic performance at rest in patients with prolonged intrinsic AV conduction (first-degree AV block). We studied 17 patients (8 men, aged 69 ± 9 years) with dual chamber pacemakers implanted for sick sinus syndrome in 15 patients and paroxysmal high degree AV block in 2 patients. Aortic flow and mitral flow were evaluated using Doppler echocardiography. Study protocol included the determination of the optimal A V delay in the DDD mode and comparison between AAI and DDD with optimal A V delay for pacing rate 70/min and 90/min. Stimulus-R interval during AAI (AHI) was 282 ± 68 ms for rate 70/min and 330 ± 98 ms for rate 90/min (P < 0.01). The optimal A V delay was 159 ± 22 ms, A V delay optimization resulted in an increase of an aortic flow time velocity integral (AFTVI) of 16%± 9%. At rate 70/min the patients with ARI , 270 ms had higher AFTVI in AAI than in DDD (0.214 ± 0.05 m vs 0.196 ± 0.05 m, P < 0.01), while the patients with ARI > 270 ms demonstrated greater AFTVI under DDD compared to AAI(0.192 ± 0.03 m vs 0.166 ± 0.02 m, P < 0.01). At rate 90/min AFTVI was higher during DDD than AAI (0.183 ± 0.03 m vs 0.162 ± 0.03 m, P < 0.01). Mitral flow time velocity integral (MFTVI) at rate 70/min was higher in DDD than in AAI (0.189 ± 0.05 m vs 0.173 ± 0.05 mP < 0.01), while at rate 90/min the difference was not significant in favor of DDD (0.149 ± 0.05 m vs 0.158 ± 0.04 m). The results suggest that in patients with first-degree AV block the relative impact of DDD and AAI pacing modes on the systolic performance depends on the intrinsic AV conduction time and on pacing rate. [source] | ||||||||||