Aims: Current guidelines recommend cardiac resynchronization therapy (CRT) in selected heart failure patients, but do not precisely clarify when a back-up implantable cardioverter defibrillator (ICD) should be associated (CRT-D). In this study we evaluate the occurrence of ventricular arrhythmias in a population of patients implanted with biventricular pacemaker without a back-up ICD (CRT-P).
Methods: We performed a retrospective analysis on 84 patients (55 men, mean age 74 ± 7 years), implanted with a CRT-P since April 2000. Patients had in 31% an underlying coronary artery disease, in 56% an idiopatic dilated cardiomyopathy and in 13% a valvular disease. An upgrade to CRT-P was performed from previous conventional pacemakers in 36% of cases. Baseline New York Heart Association (NYHA) functional class was II in 25%, III in 63% and IV in 12%. Mean left ventricular ejection fraction was 29.8 ± 8.8% with two-dimensional echo. During follow-up, occurrence of ventricular arrhythmias was assessed clinically and through the pacemaker stored data at the scheduled check-up.
Results: During a mean follow-up of 29 months (range 2-127 months), telemetry interrogation revealed unsustained ventricular tachyarrhythmias in 11 of 84 patients (13.1%). Only one patient experienced an episode of sustained ventricular tachycardia. An upgrading to a CRT-D was performed in two patients; one of these patients died suddenly 15 months after the upgrade. Death occurred in 20 of 84 patients (23.8%): 15 for refractory heart failure and five for noncardiac causes.
Conclusion: Our data show that CRT-P may be well tolerated in selected patients even during a long-term follow-up; and that an upgrade to CRT-D may not be enough to prevent sudden death.