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Background: The results of previous studies investigating the association between atrial fibrillation (AF) and central sleep apnea (CSA) in patients with left ventricular (LV) systolic dysfunction are contradictory., Methods: We prospectively enrolled 267 patients in this cross-sectional study with LV ejection fractions ≤50%, who were screened for sleep disordered breathing using cardiorespiratory polysomnography after patients with predominantly obstructive sleep apnea or insufficient sleep studies had been excluded., Results: AF at study entry was found in 70 of 267 patients (26%). CSA with an apnea/hypopnea index (AHI) ≥15/hour was present in 116 patients (43%) and 67 patients (25%) had severe CSA with an AHI > 30/hour. Univariate analysis revealed a significant association between AF and severe CSA, age, male gender, arterial hypertension, left atrial diameter, brain natriuretic peptide, chronic kidney disease, New York Heart Association class, digitalis, and the lack of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. Multivariate analysis revealed a significant association between AF and severe CSA (odds ratio [OR]: 5.21; 95% confidence interval [CI]: 1.67-16.27, P = 0.01), age (OR: 1.22 per 5-year increase; 95% CI: 1.05-1.40, P = 0.01), left atrial diameter (OR 1.61 per 5-mm increase; 95% CI: 1.22-2.01, P < 0.01), and digitalis (OR: 2.7; 95% CI: 1.26-5.79, P = 0.01)., Conclusions: AF is associated with severe CSA but not with moderate CSA in addition to age, use of digitalis, and left atrial size in patients with LV systolic dysfunction. Future studies evaluating the potential benefit of adaptive servo-ventilation therapy to prevent AF or to decrease the AF burden in heart failure patients should therefore focus on patients with severe central sleep apnea., (© 2014 Wiley Periodicals, Inc.)

Study Objectives: To examine the prevalence and clinical significance of sleep-disordered breathing in patients with implantable cardioverter defibrillators (ICD)., Methods and Results: Overnight sleep studies were performed in 129 ICD recipients who had no history of sleep apnea. The mean left ventricular ejection fraction (LVEF) was 29 +/- 11%. Mild, moderate, and severe sleep apnea was diagnosed in the presence of an apnea/hypopnea index (AHI) of 5-15/h, 15.1-30/h, and >30/h, respectively. No sleep apnea was present in 49 patients (38%), 57 (44%) had central sleep apnea (CSA), and 23 patients (18%) had obstructive sleep apnea (OSA). Mild, moderate, and severe sleep apnea were present in 25%, 31%, and 44% of patients with CSA, compared with 52%, 22%, and 26% of patients with OSA (P < 0.05). LVEF was similar in patients with versus without OSA or CSA. Patients with CSA were significantly older and had a higher prevalence of ischemic cardiomyopathy than patients without sleep apnea., Conclusions: Previously undiagnosed CSA is common in ICD recipients. Severely disordered breathing during sleep was more prevalent among patients with CSA than patients with OSA. This prospective, observational study will examine the long-term clinical significance of sleep-disordered breathing in ICD recipients.

Aims of the Study: To examine the patterns of use, complication rates, and survival in elderly recipients of implantable cardioverter defibrillators (ICD)., Methods and Results: We followed 500 consecutive patients included in the Marburg Defibrillator database for 48+/-39 months. There were 40 patients (8%) >/= 75 and 460 (92%) < 75 years of age at the time of implant. The 5-year Kaplan-Meier estimate for appropriate treatment of VT or VF by ICD was 49% among patients < 75- versus 57% among patients >/= 75-years-old (P = 0.17). The 5-year sudden death rate was similarly low in both groups of patients (2% versus 3%). The 5-year overall mortality rate was significantly higher in patients >/= 75 than in patients < 75 years of age (55% versus 21%, P = 0.001), due to a higher mortality from heart failure (HF). All procedure-related, lead-related, and pulse generator-related complications were similar in both patient groups (23% versus 25%)., Conclusions: ICD therapy was equally effective in patients >/= 75 and patients < 75 years of age in the prevention of sudden cardiac death. While the complication rates were similar in both age groups, the long-term mortality was considerably higher in elderly patients, due to a higher mortality from HF. The current ICD therapy guidelines appear applicable to elderly patients who are otherwise medically stable and without advanced HF.

Aims: Antitachycardia pacing (ATP) has not routinely been used in patients who received implantable cardioverter defibrillators (ICDs) for primary prevention of sudden death. This study investigated the efficacy of empirical ATP to terminate rapid ventricular tachycardia (VT) in heart failure patients with prophylactic ICD therapy., Methods and Results: Ninety-three patients with a mean left ventricular ejection fraction of 22 +/- 7% (range: 9-35%) due to nonischemic or ischemic cardiomyopathy received prophylactic ICDs with empiric ATP. At least 2 ATP sequences with 6-pulse burst pacing trains at 81% of VT cycle length (CL) were programmed in one or two VT zones for CL below 335 +/- 23 ms and above 253 +/- 18 ms. Ventricular flutter and fibrillation (VF) with CL below 253 +/- 18 ms were treated in a separate VF zone with ICD shocks without preceding ATP attempts. During 38 +/- 27 months follow-up, 339 spontaneous ventricular tachyarrhythmias occurred in 36 of 93 study patients (39%). A total of 232 VT episodes, mean CL 293 +/- 22 ms, triggered ATP in 25 of 36 patients with ICD interventions (69%). ATP terminated 199 of 232 VT episodes (86%) with a mean CL of 294 +/- 23 ms in 23 of 25 patients (88%) who received ATP therapy. ATP failed to terminate or accelerated 33 of 232 VT episodes (14%) with a mean CL of 287 +/- 19 ms in 12 of 25 patients (48%) who received ATP therapy., Conclusions: Painfree termination of rapid VT with empirical ATP is common in heart failure patients with prophylactic ICD therapy. The occasional inability of empiric ATP to terminate rapid VT in almost 50% of patients who receive ATP for rapid VT warrants restrictive ICD programming with regard to the number of ATP attempts in order to avoid syncope before VT termination occurs.

Background: Although more than 150,000 implantable cardioverter defibrillators (ICDs) are implanted yearly worldwide, only few studies systematically examined complications of ICD therapy in large patient cohorts., Methods: We prospectively analyzed ICD-related complications in 440 consecutive patients who underwent first implantation of an ICD system for primary or secondary prevention of sudden cardiac death within the last 10 years at our institution. All study patients received pectoral nonthoracotomy ICD lead systems with the exception of one patient who had an artificial tricuspid valve., Results: During 46 +/- 37 months follow-up, 136 of 440 patients (31%) experienced at least one complication including implant procedure-related complications in 43 patients (10%), ICD generator-related complications in 28 patients (6%), lead-related complications in 52 patients (12%), and inappropriate shocks in 54 patients (12%). The most serious complications included one perioperative death due to heart failure (0.2%), two ICD system infections necessitating device removal (0.5%) and two perioperative cerebrovascular strokes (0.5%)., Conclusions: We conclude that more than one quarter of ICD patients experience complications during a mean follow-up of almost 4 years, although serious complications such as intraoperative death or ICD system infections are rare in patients with nonthoracotomy ICD systems. Recognition of these complications is the prerequisite for advances in ICD technology and management strategies to avoid their recurrence.

Unlabelled: This study examined the relation between heart rate variability (HRV) and baroreflex sensitivity (BRS) and subsequent major arrhythmic events (MAE), defined as sustained VT, VF or sudden death, in 263 patients with idiopathic dilated cardiomyopathy (IDC) in sinus rhythm. The predefined measure of HRV was the standard deviation of all normal-to-normal RR intervals (SDNN) on baseline 24-hour ambulatory ECG. BRS was determined by the phenylephrine method. Over 52 +/- 21 months of follow-up, MAE occurred in 38 patients (14%). SDNN at baseline 24-hour ambulatory ECG (106 +/- 46 vs 109 +/- 45, ns) and BRS (7.9 +/- 5.5 vs 7.7 +/- 5.3 ms/mmHg, ns) were both similar in patients with versus without MAE during follow-up. In contrast, left ventricular ejection fraction was significantly lower in patients with versus without MAE (24%+/- 7% vs 31%+/- 10%, P < 0.019., Conclusions: Neither HRV nor BRS predicted MAE in patients with IDC.

We analyzed the serum concentrations of high-sensitivity C-reactive protein (hsCRP) at the time of diagnostic cardiac catheterization in 198 patients with idiopathic dilated cardiomyopathy (IDC) to evaluate its prognostic value. Patients were dichotomized according to a median value of hsCRP of 2 mg/dL. Predefined study endpoints over 69 +/- 33 months of follow-up included major arrhythmic events and transplant-free survival. Major arrhythmic events during follow-up occurred in 20 of 98 patients (20%) with low, compared to 22 of 100 patients (22%) with high hsCRP (ns). By multivariate analysis, a depressed left ventricular ejection fraction (LVEF) was the only significant predictor of arrhythmic risk. Death or cardiac transplantation was observed in 36% of patients with high, versus 22% of patients with low hsCRP (P < 0.05). By multivariate analysis, hsCRP and LVEF were independent predictors of transplant-free survival. Thus, in this patient population with IDC, hsCRP had independent prognostic value with regard to transplant-free survival, but did not contribute in the stratification with regard to arrhythmic risk.

This study examined the prognostic significance of the rate and length of non-sustained (NS) ventricular tachycardia (VT) on 24-hour ambulatory electrocardiograms (ECG) recorded in 343 patients with idiopathic dilated cardiomyopathy (IDC) in the prospective Marburg Cardiomyopathy study. NSVT was defined as >/=3 consecutive ventricular premature beats at >120 bpm. During 52 +/- 21 months of follow-up, major arrhythmic events defined as sustained VT, VF, or sudden cardiac death occurred in 46 of 343 patients (13%). Patients with 3-4 beat runs of NSVT had a similar arrhythmia-free survival as patients without NSVT on baseline 24-hour ambulatory ECG. The incidence of major arrhythmic events during follow-up increased significantly from 2% per year in patients without NSVT, to 5% per year in patients with 5-9 beat runs of NSVT, to 10% per year in patients with >/=10 beat runs of NSVT (P < 0.05). Unlike the length, the rate of NSVT was similar in patients with versus without subsequent major arrhythmic events (163 +/- 23 vs 160 +/- 24 bpm). Thus, the length but not the rate of NSVT on 24-hour ambulatory ECG was a predictor of major arrhythmic events in patients with IDC. The presence of NSVT with >/=10 beat runs on ambulatory ECG was associated with a particularly high risk of major arrhythmic events.

We monitored reverse left ventricular (LV) remodeling and LV function during the first 6 months of cardiac resynchronization therapy (CRT) in 34 patients (mean age = 55.3 +/- 13.6 years, 28 men) with dilated cardiomyopathy (DCM), left bundle branch block, in stable New York Heart Association class III, and on fixed drug regimen who underwent implantation of CRT systems with or without cardioverter defibrillator back-up. QRS-complex duration was reduced from 169.69 +/- 19.6 ms (SD) to 144.1 +/- 23.4 ms during CRT. Parasternal M-mode and apical 2D-echocardiography was performed before and 3 and 6 months after device implantation. LV enddiastolic (EDD) and endsystolic (ESD) diameters were measured, and biplane LV enddiastolic (EDV), and endsystolic (ESV) volumes and ejection fractions (EF) were calculated using a modified Simpson formula. Significant decreases in LVEDD (P = 0.0064 at 3 months and P = 0.021 at 6 months), LVESD (P = 0.023 at 3 months, and P = 0.003 at 6 months), and LVESV (P = 0.006 resp. P = 0.007), and increases in LVEF (P = 0.003 at 3 months and P < 0.001 at 6 months) were observed. Mean LVEF increased from 23% at baseline to 39% at 6 months. CRT induced prominent reverse LV remodeling and significantly increased LVEF within a few months in patients with DCM.

This study investigated the relation between heart rate variability (HRV) measured as standard deviation of normal to normal RR intervals (SDNN) on baseline 24-hour ambulatory electrocardiogram (ECG) and subsequent appropriate implantable cardioverter defibrillator (ICD) interventions in 70 patients with idiopathic dilated cardiomyopathy (IDC) in whom ICDs were implanted prophylactically in the presence of a low left ventricular ejection fraction (LVEF). During 43 +/- 26 months of follow-up, 26 of 70 (37%) study patients with IDC received one or more appropriate ICD interventions for sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) documented by electrograms stored in the ICD. Mean SDNN at ICD implant was 94 +/- 33 ms. No difference was found between patients with (90 +/- 25 ms) versus without (96 +/- 37 ms) appropriate ICD interventions for VT or VF during follow-up. Multivariate Cox regression analysis of baseline clinical characteristics including age, gender, LVEF, NYHA functional class, nonsustained VT on Holter, history of syncope, left bundle branch block, baseline medication and HRV revealed LVEF as the only significant predictor of arrhythmia. These findings do not support the use of HRV measured as SDNN on 24-hour ambulatory ECG to select patients with IDC for prophylactic ICD therapy.

The clinical and electrocardiographic Marburg Cardiomyopathy database was analyzed to identify potential candidates for cardiac resynchronization therapy (CRT) with biventricular or left ventricular pacing among 566 patients with dilated cardiomyopathy (DCM). All of the following restrictive selection criteria were fulfilled by 38 patients (7%): NYHA functional class > or = 3 (n = 193, 34%), left ventricular ejection fraction (LVEF) < 30% (n = 238, 42%), sinus rhythm (n = 437, 77%), left bundle branch block (LBBB, n = 142, 25%), and QRS duration > or = 150 ms (n = 136, 24%). In 78 of the 566 patients (14%) all of the following less restrictive selection criteria were fulfilled: NYHA functional class > or = 3 (n = 193, 34%), LVEF < 35% in presence of any underlying rhythm (n = 326, 58%), QRS duration > or = 120 ms with right or left bundle branch block (n = 223, 39%). Thus, between 7% and 14% of patients with DCM were candidates for CRT depending on the application of strict versus less restrictive selection criteria.