Incremental benefit of cardiac resynchronisation therapy with versus without a defibrillator.

OBJECTIVE: To determine the incremental value of implantable cardioverter defibrillators (ICD) in contemporary optimally treated patients with heart failure (HF) undergoing cardiac resynchronisation therapy (CRT). METHODS: Consecutive patients with HF undergoing CRT-pacemaker (CRT-P) or CRT-defibrillator (CRT-D) implantation in a single tertiary care centre between October 2008 and August 2015 were retrospectively evaluated. For patients with a primary prevention indication of the CRT-D, no benefit of the ICD was defined as absence of appropriate therapy (device analysis) or lethal ventricular tachyarrhythmias (mode of death analysis) during follow-up. RESULTS: 687 patients (CRT-P/CRT-D; n=361/326) were followed for 38±22 months. CRT-P recipients were older (75.7±9.1 vs 71.8±9.3 years; p<0.001) and had a higher comorbidity burden. Five patients with CRT-P (1%) experienced episodes of sustained ventricular-tachycardia vs 64 (20%) patients with CRT-D (p<0.001). Remote tele-monitoring detected the episodes of sustained ventricular tachycardia in four patients with CRT-P, allowing for elective upgrade to CRT-D. All-cause mortality was higher in patients with CRT-P versus CRT-D (21% vs 12%, p=0.003), even after adjusting for baseline characteristics (HR 2.5; 95% CI 1.36 to 4.60; p=0.003). However, mode of death analysis revealed a predominant non-cardiac mode of death in CRT-P recipients (n=47 (71%) vs n=13 (38%) in CRT-D, p=0.002). Multivariate analysis revealed that age >80 years, New York Heart Association class IV, intolerance to beta-blockers and underlying non-ischaemic cardiomyopathy were independently associated with little incremental value of a primary prevention ICD on top of CRT. CONCLUSIONS: The majority of patients with contemporary HF as currently selected for CRT-P exhibit mainly non-cardiac-driven mortality. Weighing risk of ventricular-tachyarrhythmic death versus risk of all-cause mortality helps to address the incremental value of an ICD to CRT-P.

Feasibility and Association of Neurohumoral Blocker Up-titration After Cardiac Resynchronization Therapy.

BACKGROUND: Cardiac resynchronization therapy (CRT) improves mortality and morbidity on top of optimal medical therapy in heart failure with reduced ejection fraction (HFrEF). This study aimed to elucidate the association between neurohumoral blocker up-titration after CRT implantation and clinical outcomes. METHODS AND RESULTS: Doses of angiotensin-converting enzyme inhibitors (ACE-Is), angiotensin receptor blockers (ARBs), and beta-blockers were retrospectively evaluated in 650 consecutive CRT patients implanted from October 2008 to August 2015 and followed in a tertiary multidisciplinary CRT clinic. All 650 CRT patients were on a maximal tolerable dose of ACE-I/ARB and beta-blocker at the time of CRT implantation. However, further up-titration was successful in 45.4% for ACE-I/ARB and in 56.8% for beta-blocker after CRT-implantation. During a mean follow-up of 37 ± 22 months, a total of 139 events occurred for the combined end point of heart failure admission and all-cause mortality. Successful, versus unsuccessful, up-titration was associated with adjusted hazard ratios of 0.537 (95% confidence interval 0.316-0.913; P = .022) for ACE-I/ARB and 0.633 (0.406-0.988; P = .044) for beta-blocker on the combined end point heart failure admission and all-cause mortality. Patients in the up-titration group exhibited a similar risk for death or heart failure admission as patients treated with the maximal dose (ACE-I/ARB: P = .133; beta-blockers: P = .709). CONCLUSIONS: After CRT, a majority of patients are capable of tolerating higher dosages of neurohumoral blockers. Up-titration of neurohumoral blockers after CRT implantation is associated with improved clinical outcomes, similarly to patients treated with the guideline-recommended target dose at the time of CRT implantation.

Usefulness of cardiac resynchronization therapy in patients with Adriamycin-induced cardiomyopathy.

Adriamycin is a chemotherapeutic agent that can cause severe cardiotoxicity, which potentially carries a poorer long-term prognosis than other forms of cardiomyopathy. Cardiac resynchronization therapy (CRT) has been shown to improve quality of life, exercise capacity, left ventricular ejection fraction, and survival in selected patients with heart failure. It is unclear if patients with Adriamycin-induced cardiomyopathy (AIC) respond to CRT. We reviewed clinical and echocardiographic data on 18 consecutive patients with AIC who underwent implantation of a CRT device at the Cleveland Clinic from February 2000 to April 2007. Changes in clinical and echocardiographic parameters were compared to 189 consecutive patients with other forms of nonischemic cardiomyopathy (NIC) using similar end points. Patients with AIC demonstrated significant improvements in ejection fraction, left ventricular end-diastolic and end-systolic diameters, mitral regurgitation, and New York Heart Association functional class with CRT. These changes were similar to patients in the NIC cohort. In conclusion, patients with AIC may derive a significant echocardiographic and symptomatic benefit from CRT, which is similar to that seen in other forms of NIC.