Arrhythmic and mortality outcomes in patients with dilated cardiomyopathy receiving cardiac resynchronization therapy without defibrillator.

Introduction: The routine implantation of cardiac resynchronization therapy with defibrillators in all patients who are candidates for this treatment is now being negotiated, mainly in patients with dilated cardiomyopathy.

Objective: We investigated the arrhythmic and mortality outcomes following CRT implantation in DCM, as well as the necessity for defibrillator capabilities in that particular group of patients.

Methods: we included 67- patients with DCM with EF ≤ 35%, QRS duration >130 msec and NYHA class II-IV, or those with EF ≤ 35% with indications of permanent pacing for implantation of CRT-P. Patients were followed to obtain good CRT response. Improved clinical outcomes were defined as improvement in at least one NYHA class, ≥5% increase in LVEF, and ≥15% reduction in left ventricular end-systolic volume versus baseline. Patients were classified into responder and non-responder. Patients were followed for 36 months regarding all-cause morbidity mainly ventricular tachycardia and all-cause mortality.

Results: CRT responder patients had better clinical outcomes than CRT non-responder patients (post NYHA, 1.3 ± 0.5 vs. 2.5 ± 0.6, p < 0.0001; post LVEF 30.0 ± 1.6 vs. 20.3 ± 2.2%, p < 0.0001; LVESV, 151.7 ± 7.6 vs. 190.4 ± 9.0 ml, p < 0.0001), with lower ventricular arrhythmia (p < 0.0001), lower mortality (p = 0.015) and lower all-cause morbidity (p < 0.001). This survival advantage may be related to the response to CRT response determined by clinical and echocardiographic parameters over a 36-month period of follow-up.

Conclusions: Our findings suggest that CRT-P implantation without defibrillation backup is an encouraging treatment option for patients with DCM, principally those who responded to it. It may result in cost savings, a decrease in complications, and an improvement in all-cause morbidity, particularly ventricular arrhythmia and survival.