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Dual-chamber Pacemaker (dual-chamber + pacemaker)
Selected AbstractsEffect 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] Malignant Ventricular Arrhythmia in a Case of Adult Onset of Spinal Muscular Atrophy (Kugelberg,Welander Disease)JOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 3 2009MARKUS ROOS M.D. We present a case of a 43-year-old male patient with adult onset of spinal muscular atrophy (SMA). The patient first came to our attention with atrioventricular (AV) block. A dual-chamber pacemaker (DDD-PM) was implanted. Four years later, the PM data log showed occurrence of frequent episodes of nonsustained ventricular tachycardia (NSVT). The episodes progressed in duration and frequency. An electrophysiological study revealed prolonged His-ventricular (HV) interval duration and induction of sustained ventricular tachycardia. The patient was successfully upgraded to a prophylactic dual-chamber cardioverter defibrillator. Our case is the first description of a patient with adult-onset SMA (Kugelberg,Welander disease [KWD]) and malignant ventricular arrhythmias. [source] Autonomic Function during Closed Loop Stimulation and Fixed Rate Pacing: Heart Rate Variability Analysis from 24-Hour Holter RecordingsPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 3 2010RAFFAELE QUAGLIONE M.D. Aim: Aim of this retrospective study was to analyze the effect of closed-loop stimulation (CLS) and DDD pacing mode on autonomic balance, and to evaluate heart rate variability (HRV) during CLS stimulation. Methods and Materials: Autonomic balance was estimated by a 24-hour HRV analysis of paced and spontaneous beats in patients implanted with a dual-chamber pacemaker (Inos2+ CLS,Biotronik GmbH, Berlin, Germany) and randomly assigned to CLS or DDD pacing mode. Patients underwent two 24-hour electrocardiogram Holter recordings at the end of each 3-month pacing mode period. Each Holter recording was automatically scanned to extract sequences of consecutive beats of the same type [atrial paced (Ap)-sequence and atrial spontaneous (As)-sequence], lasting at least 130 beats. Results: Eight hundred and ten sequences were extracted from 15 patients, and the following spectral parameters were evaluated during both CLS and DDD mode: the total power (variance), the absolute and percentage (relative to the total power) powers of the low frequency (LF, 0.04,0.15 Hz) and high frequency (HF, 0.15,0.4 Hz) components, as well as the LF/HF power ratio. Discussion: The two main findings of this study were: in all the patients, CLS seems to mimic short-term physiological HRV, although the variability (total power) was lower than that relative to the spontaneous beats; the HRV of the spontaneous beats had an higher LF/HF when the pacemaker was programmed as DDD respect to CLS, consistent with a shift toward sympathetic predominance. PACE 2010; 33:337,342) [source] The Significance of Pulse Oximetry in the Diagnosis of Pacemaker Failure to OutputANNALS OF NONINVASIVE ELECTROCARDIOLOGY, Issue 3 2010Athanasios Michailidis M.D. In a routine monitor electrocardiogram few hours after implantation of a dual-chamber pacemaker, there was a suspicion of ventricular oversensing leading to failure to output. Pulse oximeter plethysmographic wave signal virtually excluded this suspicion. This case report demonstrates the clinical utility of initial pulse oximeter wave analysis in excluding pacemaker failure to output. Ann Noninvasive Electrocardiol 2010;15(3):293,295 [source] Interatrial Mechanical Dyssynchrony Worsened Atrial Mechanical Function in Sinus Node Disease With or Without Paroxysmal Atrial FibrillationJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 11 2009MEI WANG M.D., Ph.D. Introduction: Atrial electromechanical dysfunction might contribute to the development of atrial fibrillation (AF) in patients with sinus node disease (SND). The aim of this study was to investigate the prevalence and impact of atrial mechanical dyssynchrony on atrial function in SND patients with or without paroxysmal AF. Methods: We performed echocardiographic examination with tissue Doppler imaging in 30 SND patients with (n = 11) or without (n = 19) paroxysmal AF who received dual-chamber pacemakers. Tissue Doppler indexes included atrial contraction velocities (Va) and timing events (Ta) were measured at midleft atrial (LA) and right atrial (RA) wall. Intraatrial synchronicity was defined by the standard deviation and maximum time delay of Ta among 6 segments of LA (septal/lateral/inferior/anterior/posterior/anterospetal). Interatrial synchronicity was defined by time delay between Ta from RA and LA free wall. Results: There were no differences in age, P-wave duration, left ventricular ejection fraction, LA volume, and ejection fraction between with or without AF. Patients with paroxysmal AF had lower mitral inflow A velocity (70 ± 19 vs 91 ± 17 cm/s, P = 0.005), LA active empting fraction (24 ± 14 vs 36 ± 13%, P = 0.027), mean Va of LA (2.6 ± 0.9 vs 3.4 ± 0.9 cm/s, P = 0.028), and greater interatrial synchronicity (33 ± 25 vs 12 ± 19 ms, P = 0.022) than those without AF. Furthermore, a lower mitral inflow A velocity (Odd ratio [OR]= 1.12, 95% Confidence interval [CI] 1.01,1.24, P = 0.025) and prolonged interatrial dyssynchrony (OR = 1.08, 95% CI 1.01,1.16, P = 0.020) were independent predictors for the presence of AF in SND patients. Conclusion: SND patients with paroxysmal AF had reduced regional and global active LA mechanical contraction and increased interatrial dyssychrony as compared with those without AF. These findings suggest that abnormal atrial electromechanical properties are associated with AF in SND patients. [source] Time-Domain and Morphological Analysis of the P Wave.PACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 8 2008Part II: Effects of Atrial Pacing on P-Wave Features Background: The aim of this study was to compare time-domain and morphological descriptors of paced and spontaneous P wave in patients prone to atrial fibrillation (AF). Methods: Nineteen patients (nine women, aged 72 ± 10 years) affected by paroxysmal AF and implanted with dual-chamber pacemakers (PM) were studied. Two 5-minute recordings were performed during spontaneous and paced rhythm. Electrocardiogram (ECG) signals were acquired using a 32-lead mapping system. Patients were grouped into two classes: no previous AF and previous AF groups, according to the number of AF episodes in the 6 months before the analysis. Results and Conclusion:During atrial pacing P wave appeared prolonged and morphologically more complex with respect to sinus rhythm. We also found that in patients at lower risk for AF, the atrial pacing changes the atrial activation to a greater extent than in patients at higher risk for AF. Finally, all time-domain and morphological descriptors of the P wave except one succeed in discriminating "no previous AF" and "previous AF" patients in spontaneous rhythm, while no significant differences have been observed during pacing for any parameters. [source] Reduction of RV Pacing by Continuous Optimization of the AV IntervalPACING AND CLINICAL ELECTROPHYSIOLOGY, Issue 4 2006GORAN MILASINOVIC Background: In patients requiring permanent pacing, preservation of intrinsic ventricular activation is preferred whenever possible. The Search AV+ (SAV+) algorithm in Medtronic EnPulseÔ dual-chamber pacemakers can increase atrioventricular (AV) intervals to 320 ms in patients with intact or intermittent AV conduction. This prospective, multicenter study compared the percentage of ventricular pacing with and without AV interval extension. Methods: Among 197 patients enrolled in the study, the percentage of ventricular-paced beats was evaluated via device diagnostics at the 1-month follow-up. Patient cohorts were defined by clinician assessment of conduction via a 1:1 AV conduction test at the 2-week follow-up. The observed percentage of ventricular pacing with SAV + ON and the predicted percentage of ventricular pacing with SAV + OFF were determined from the SAV + histogram data for the period between the 2-week and 1-month follow-up visits. Results: Of 197 patients, 110 (55.8%) had intact 1:1 AV conduction, of which 109 had 1-month data. SAV + remained ON in 99/109 patients; 10 patients had intrinsic A-V conduction intervals beyond SAV + nominal and therefore SAV + disabled. The mean percentage of ventricular pacing in the 109 patients was SAV+ ON = 23.1% (median 3.7%) versus SAV + OFF = 97.2% (median 99.7%). In 87 patients without 1:1 AV conduction, SAV + was programmed OFF in 6, automatically disabled in 52, and remained ON in 29. In 8 of these patients, 80,100% reduction in ventricular pacing was observed with SAV + ON. Conclusion: The Search AV+ algorithm in the EnPulse pacemaker effectively promotes intrinsic ventricular activation and substantially reduces unnecessary ventricular pacing. [source] | ||||||||||