Extraordinarily favorable left ventricular reverse remodeling through long-term cardiac resynchronization: super-response to cardiac resynchronization.

BACKGROUND: Some chronic heart failure (CHF) patients show remarkable improvement in left ventricular (LV) remodeling after cardiac resynchronization therapy (CRT), for unclear reasons. This study aimed at identifying predictors of an extraordinarily favorable response to CRT. METHODS: We studied 136 CRT patients (104 men, median 66 years, QRS 162 ms, left ventricular ejection fraction 24 ± 7%, 70% coronary disease, all left bundle branch block [LBBB]). We measured LV end diastolic diameter (LVEDD) before and after long-term (9.4 ± 6.3 months) CRT. At baseline, LV pre-ejection interval (LVPEI), interventricular mechanical delay (IVMD), LV dyssynchrony (standard deviation of electromechanical delays [SDEMD] in eight LV segments), exercise capacity (pVO(2)), and ventilatory efficiency (VE/VCO(2)) were assessed. Patients with a LVEDD reduction beyond the 80th percentile (high responders [HR]) were compared to low responders (LR). RESULTS: In the HR group (n = 22), LVEDD was reduced from 71 to 52 mm (LR 64-61 mm, P < 0.001). HR had predominantly nonischemic heart disease (HR: 72%, LR: 44%, P = 0.019), tended to have a wider QRS (HR: 178 ms, LR: 162 ms, P = 0.066), had a longer LVPEI (HR: 179 ms, LR: 155 ms, P = 0.004), wider IVMD (HR: 60 ms, LR 48 ms, P = 0.05), larger LVEDD (P = 0.002), higher SDEMD (HR: 69 ms, LR: 46 ms, P = 0.044), but higher pVO(2) (HR: 17.5 mL/min/kg, LR: 13.5 mL/kg/min, P = 0.025) and lower VE/VCO(2) (HR: 31, LR: 35, P = 0.043), all compared to LR patients. CONCLUSION: Extraordinarily favorable reverse LV remodeling through CRT in CHF and LBBB appears to require a particularly dilated LV due to nonischemic heart disease with pronounced electromechanical alteration, but with a fairly preserved functional capacity before CRT.

Ventricular tachycardia or ventricular fibrillation occurs less often in patients with left bundle branch block and combined resynchronization and defibrillators than in patients with narrow QRS and conventional defibrillators.

AIMS: Mortality in chronic heart failure (CHF) patients with left bundle branch block (LBBB) is high. Cardiac resynchronization therapy (CRT) reduces symptoms and mortality in CHF patients with LBBB. Whether CRT promotes or prevents ventricular tachycardia (VT)/ventricular fibrillation (VF) remains controversial, however. Therefore, we aimed to analyse arrhythmia-related CRT effects and characterized the VT/VF incidence in CRT-defibrillator patients and matched controls with conventional implantable cardioverter-defibrillators (ICDs) for primary prevention of sudden cardiac death. METHODS AND RESULTS: We enrolled 134 patients [110 men, left ventricular ejection fraction (LVEF) 24 ± 8%, 71 coronary artery disease, CRT-ICD 67, conventional ICD matched controls 67, follow-up 31 ± 17 months] and monitored overall survival and the time to a first VT/VF episode. Controls did not have LBBB. They were otherwise matched for age, LVEF, and follow-up duration. Gender and underlying disease did not differ between the groups. Kaplan-Meier analysis revealed more favourable arrhythmia-free survival in CRT-ICD vs. conventional ICD patients [hazard ratio (HR) 2.26, confidence interval (CI) 1.09-4.67, log rank P = 0.023]. The difference persisted in the multivariate Cox regression analysis (HR 3.25, CI 1.18-8.93, P= 0.022). Overall survival was similar in both groups (HR 1.45, CI 0.55-3.82, P = 0.45). CONCLUSIONS: Chronic heart failure patients with LBBB treated with CRT-ICD, experience less and delayed VT/VF episodes compared with matched controls without LBBB receiving conventional ICD. In the long-term, CRT appears to exert antiarrhythmic effects and to attenuate the particularly high arrhythmia-related risk of CHF patients with LBBB. The incremental benefit of adding the ICD option to CRT pacing in LBBB patients appears questionable.

Long-term survival of routine implantable cardioverter/defibrillator recipients appears to be significantly impaired with concomitant diuretics and improved with aldosterone antagonists.

Evidence-based treatment for heart failure (HF) comprises beta-blockers, angiotensin converting enzyme inhibitors, angiotensin receptor blockers, and aldosterone receptor antagonists (ARA). Diuretics (DR) are prescribed in acute and chronic HF, but their impact on survival and ventricular tachyarrhythmias (VT/VF) is unclear. The present observational study aims to examine the influence of DR and ARA on survival and appropriate cardioverter/defibrillator (ICD) treatment episodes in routine ICD patients. In 352 consecutive ICD patients (291 men, 60 ± 12 years, LVEF 34 ± 15%, follow-up 37 ± 19 months) overall survival and the time to a first appropriate VT/VF episode were assessed. Electrograms were validated. Potassium and creatinine serum levels and the medical treatment regimen for heart failure were documented at baseline. Multivariate Cox regression analyses revealed significantly worse survival for patients with DR compared to those without DR (OR 0.24, CI 0.08-0.76, P= 0.016), whereas the group with ARA had better survival compared to patients without (OR 2.05, CI 1.02-4.10, P= 0.04). Patient groups did not differ regarding survival without incident VT/VF (DR+ vs. DR- OR 1.10, CI 0.67-1.83, P= 0.70; OR 0.66, CI 0.40-1.09, P= 0.10). Long-term survival appears to be compromised in ICD patients receiving concomitant DR, but is favorably influenced by ARA, although VT/VF incidence does not differ. Randomized analyses are warranted to assess long-term prognostic effects of DR in HF.

Right ventricular pacing is associated with impaired overall survival, but not with an increased incidence of ventricular tachyarrhythmias in routine cardioverter/defibrillator recipients with reservedly programmed pacing.

AIMS: Data from previous defibrillator studies raised concern about right ventricular pacing (RVP) promoting heart failure progression and mortality in implantable cardioverter/defibrillator (ICD) patients. The present observational study re-examined the association of RVP, survival, and ventricular tachyarrhythmias/ventricular fibrillation (VT/VF) in routine ICD patients with restrictively programmed pacing. METHODS AND RESULTS: In 213 ICD patients [183 men, left ventricular ejection fraction (LVEF) 37 +/- 15%, follow-up 37 +/- 18 months, no advanced atrioventricular (AV) block], the RVP proportion, survival, and the time to a first appropriate VT/VF episode were assessed. Electrograms were validated and the overall survival was determined. The RVP prevalence was dichotomized at > or = 30% (high RVP) vs. <30% (low RVP). High RVP (RVP 94%, n = 24) and low RVP (RVP 0%, n = 189) patients had similar LVEF, underlying heart disease, ICD indication, and medication. Multivariate Cox regression showed no difference in survival without appropriate VT/VF treatment [odds ratio (OR): 0.92, 95% confidence interval (CI): 0.41-2.04, P = 0.83]. Overall survival was significantly more favourable in low RVP patients (OR: 0.34, CI: 0.13-0.91, P = 0.03). CONCLUSION: Frequent RVP is associated with impaired survival in ICD patients despite conservative pacing settings. Implantable cardioverter/defibrillator patients requiring concomitant bradycardia pacing should be cared for with particular attention to clinical worsening. Right ventricular pacing prevention and alternative modalities of ventricular pacing need prospective evaluation.

Survival and appropriate device interventions in recipients of cardioverter defibrillators implanted for the primary versus secondary prevention of sudden cardiac death.

BACKGROUND: Implantable cardioverter-defibrillators (ICD) implanted after an episode of ventricular tachyarrhythmia (VTA) or in patients at high risk of VTA lower the long-term mortality. Comparisons of the clinical outcomes of the two indications are scarce. METHODS: The study enrolled 360 consecutive ICD recipients. The device was implanted for secondary prevention in 150 patients, whose mean age was 60 +/- 14 years, and mean left ventricular ejection fraction (LVEF) was 40 +/- 16%, and for primary prevention in 210 patients, whose mean age was 61 +/- 11 years, and mean LVEF was 31 +/- 13%. All-cause mortality and time to first appropriate ICD therapy were measured. RESULTS: The two study groups were similar with respect to age and prevalence of coronary artery disease. Mean LVEF was higher in the secondary prevention group (P = 0.001). Cox regression analysis revealed a significantly shorter time to first appropriate ICD therapy in the secondary prevention group (HR = 0.51, 95% CI = 0.30 - 0.87, P = 0.01). Over a mean follow-up of 37 +/- 19 months, the all-cause mortality in the overall population was 12.7%, and was similar in both subgroups (HR = 0.99, 95% CI = 0.55-1.77, P = 0.97). CONCLUSIONS: The long-term mortality in this unselected population of ICD recipients was low. Patients treated for secondary prevention received earlier appropriate ICD therapy than patients treated for primary prevention. Long-term mortality was similar in both groups. The higher VT incidence of VTA was effectively treated by the ICD and was not associated with a higher mortality.

Risk selection in the German public health insurance system.

The German statutory health insurance market was exposed to competition in 1996. To limit direct risk selection the regulator required open enrollment. As the risk compensation scheme, introduced in 1994, is highly incomplete, substantial incentives for risk selection exist. Due to their low premiums, company-based sickness funds have been able to attract a lot of new members. We analyze, using data from the German Socio-Economic Panel, the determinants of switching behavior from 1995 to 2000. There is no evidence for selection by funds. The success of the company-based sickness funds originates in incomplete risk adjustment together with the negative correlation between health status and switching costs.