Heart failure
Long-Term Survival of Patients With Heart Failure and Ventricular Conduction Delay Treated With Cardiac Resynchronization Therapy

https://doi.org/10.1016/j.amjcard.2006.07.087Get rights and content

This multicenter longitudinal observational trial was designed to analyze the long-term outcome of patients with heart failure (HF) treated with cardiac resynchronization therapy (CRT) alone or with implantable cardioverter-defibrillator (ICD) backup in a daily practice scenario. It is unknown whether the magnitude of survival benefits conferred by CRT in a daily practice scenario is comparable to what has been observed in randomized controlled trials and whether this benefit is sustained over the long term. The outcome of 1,303 consecutive patients with ischemic or nonischemic cardiomyopathy on optimal pharmacologic therapy treated from August 1, 1995 to August 1, 2004 at 4 European centers with CRT alone (44%) or with ICD backup for symptomatic HF and prolonged QRS duration was assessed. Cumulative event-free survival was evaluated for a combined end point, defined as death from any cause, urgent transplantation, or implantation of a left ventricular assist device. The cumulative incidence of competing events, HF, sudden cardiac death, and noncardiac death, was also assessed. Event-free survival was similar across the different centers. At 1 and 5 years, cumulative event-free survivals were 92% (95% confidence interval [CI] 91 to 94) and 56% (95% CI 48 to 64), respectively. The cumulative incidence of HF deaths was 25.1% (95% CI 19 to 31.7), whereas that of sudden death was 9.5% (95% CI 5.1 to 15.7). Using multivariate analysis, CRT with an ICD backup was associated with a nonsignificant decrease in mortality by 20% (hazard ratio 0.83, 95% CI 0.58 to 1.17, p = 0.284), with a highly significant protective effect against sudden cardiac death (hazard ratio 0.04, 95% CI 0.04 to 0.28, p <0.002). In conclusion, patients with advanced HF and a wide QRS complex routinely treated with CRT have a favorable long-term outcome that was reproducible at different centers. The leading cause of death in these patients remained HF, and this mode of death was competing with other causes in determining outcome. Total mortality was 20% lower with ICD backup (95% CI 42% lower to 17% higher) due to a protective effect against sudden cardiac death.

Section snippets

Patients

One thousand three hundred three adult patients with moderate to severe HF caused by left ventricular systolic dysfunction (ejection fraction ≤35%) of ischemic or nonischemic origin and with ventricular conduction delay (QRS duration ≥120 ms) treated with CRT were included. All patients were consecutively treated from August 1, 1995 to August 1, 2004 at 4 European institutions using a prospectively predefined registry protocol. Patients were referred because of persistent HF symptoms despite

Patient characteristics

Outcome information could not be retrieved in 5 patients who were therefore excluded from further analysis. Characteristics of the 1,298 patients are presented in Table 1. Origin was confirmed in all patients by coronary angiography, and the cause of HF was coronary artery disease in 54% of patients. Each patient was on a median of 4 active cardiovascular drugs. About 75% of patients presented with left bundle branch block QRS morphology, and 15% of patients had been constantly paced due to

Discussion

This is the first large, long-term, prospectively defined observational study on CRT in symptomatic patients with moderate to severe HF and ventricular conduction delay. Our results extend those of previous, randomized, controlled studies of CRT on mortality5, 6, 7 showing a very favorable outcome of patients treated with CRT in real-world clinical practice. Cumulative event-free survivals were 92% and 56% at 1 and 5 years, respectively, with a high consistency across the 4 European centers.

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