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Objectives: This study was designed to assess the effects of long-term right ventricular (RV) pacing on left ventricular (LV) dyssynchrony, LV function, and heart failure symptoms., Background: Atrioventricular (AV) node ablation and subsequent long-term RV pacing is a well-established treatment option in patients with atrial fibrillation (AF)., Methods: In 55 patients with drug-refractory AF, AV node ablation and implantation of a pacemaker was performed. At baseline and after a mean of 3.8 +/- 1.7 years, LV dyssynchrony (by M-mode echocardiography and tissue Doppler imaging), LV function, and volumes and functional status were assessed., Results: After long-term RV pacing, 27 patients (49%) had developed LV dyssynchrony. Concomitantly, these patients worsened in heart failure symptoms (New York Heart Association functional class increased from 1.8 +/- 0.6 to 2.2 +/- 0.7, p < 0.05), with a decrease in LV ejection fraction (from 48 +/- 7% to 43 +/- 7%, p < 0.05) and an increase in LV end-diastolic volume (from 116 +/- 39 ml to 130 +/- 52 ml, p < 0.05). Conversely, patients without LV dyssynchrony did not deteriorate in heart failure symptoms, LV function, or LV volumes., Conclusions: Long-term RV pacing can induce LV dyssynchrony in almost 50% of patients treated with AV node ablation for chronic AF. The development of LV dyssynchrony was associated with deterioration in heart failure symptoms, systolic LV function, and LV dilatation.

Objectives: We attempted to assess the efficacy of combined cardiac resynchronization therapy-implantable cardioverter-defibrillator (CRT-ICD) in heart failure patients with and without ventricular arrhythmias., Background: Because CRT and ICDs both lower all-cause mortality in patients with advanced heart failure, combination of both therapies in a single device is challenging., Methods: A total of 191 consecutive patients with advanced heart failure, left ventricular ejection fraction <35%, and a QRS duration >120 ms received CRT-ICD. Seventy-one patients had a history of ventricular arrhythmias (secondary prevention); 120 patients did not have prior ventricular arrhythmias (primary prevention). During follow-up, ICD therapy rate, clinical improvement after 6 months, and mortality rate were evaluated., Results: During follow-up (18 +/- 4 months), primary prevention patients experienced less appropriate ICD therapies than secondary prevention patients (21% vs. 35%, p < 0.05). Multivariate analysis revealed, however, no predictors of ICD therapy. Furthermore, a similar, significant, improvement in clinical parameters was observed at 6 months in both groups. Also, the mortality rate in the primary prevention group was lower than in the secondary prevention group (3% vs. 18%, p < 0.05)., Conclusions: As 21% of the primary prevention patients and 35% of the secondary prevention patients experienced appropriate ICD therapy within 2 years after implant, and no predictors of ICD therapy could be identified, implantation of a CRT-ICD device should be considered in all patients eligible for CRT.

Objectives: The aim of this study was to evaluate the effect of a systematic screening/treatment protocol on outcome in patients after aborted sudden death., Background: Patients after aborted sudden death are at high risk for recurrent events. In this regard, systematic screening is mandatory to reveal the underlying etiology, to detect and subsequently treat reversible causes, and to establish patient-tailored antiarrhythmic treatment., Methods: A total of 417 consecutive patients after aborted sudden death due to ventricular arrhythmias underwent echocardiography and coronary angiography. In the presence of coronary artery disease and myocardial ischemia, using stress-rest myocardial perfusion imaging/exercise testing, subsequent revascularization was performed. Patients without ischemic heart disease were further evaluated with magnetic resonance imaging, contrast echocardiography, right ventricular angiography and/or flecainide/ergonovine testing. After these diagnostic steps, final antiarrhythmic therapy was based on the outcome of electrophysiologic testing., Results: The majority of patients had ischemic heart disease (n = 300, 72%). After screening, 78 (78 of 300, 26%) patients underwent revascularization. In 69% of patients, ventricular arrhythmias were inducible during electrophysiologic testing. Therapy consisted of implantable defibrillators in 301 (72%) patients, antiarrhythmic drugs in 239 (57%) patients, and catheter ablation in 58 (14%) patients. During 5-year follow-up, only 3 (<1%) patients died suddenly. The 5-year survival rate was 82%; of 39 deaths, 10 (26%) patients died due to non-cardiac disease and 26 (67%) due to heart failure., Conclusions: Screening and treatment of patients after aborted sudden death according to a standardized protocol resulted in <1% arrhythmic deaths during 5-year follow-up. The majority of patients died of heart failure, stressing the importance of optimizing medical and surgical therapy and screening.

Mechanical dyssynchrony is an important codeterminant of cardiac dysfunction in heart failure. Treatment, either medical, surgical, or by pacing, may improve cardiac function partly by improving mechanical synchrony. Consequently, the quantification of ventricular mechanical (dys)synchrony may have important diagnostic and prognostic value and may help to determine optimal therapy. Therefore, we introduced new indexes to quantify temporal and spatial aspects of mechanical dyssynchrony derived from online segmental conductance catheter signals obtained during diagnostic cardiac catheterization. To test the feasibility and usefulness of our approach, we determined cardiac function and left ventricular mechanical dyssynchrony by the conductance catheter in heart failure patients with intraventricular conduction delay (n = 12) and in patients with coronary artery disease (n = 6) and relatively preserved left ventricular function. The heart failure patients showed depressed systolic and diastolic function. However, the most marked hemodynamic differences between the groups were found for mechanical dyssynchrony, indicating a high sensitivity and specificity of the new indexes. Comparison of conductance catheter-derived indexes with septal-to-lateral dyssynchrony derived by tissue-Doppler velocity imaging showed highly significant correlations. The proposed indexes provide additional, new, and quantitative information on temporal and spatial aspects of mechanical dyssynchrony. They may refine diagnosis of cardiac dysfunction and evaluation of interventions, and ultimately help to select optimal therapy.