P1744Inappropriate therapies in primary prevention ICD patients with narrow QRS: dual or single chamber ICD? The question remains

Abstract

Background: the benefit of dual chamber ICD in reducing inappropriate therapies is modest and limited to specific patients (p) groups. We tried to determine the efficacy of dual chamber ICD among heart failure (HF) p with narrow QRS, implanted with a prophylactic ICD. Methods: we collected all HF p undergoing ICD-only implant included in the nationwide multicenter UMBRELLA registry. A committee of experts reviewed and classified all the arrhythmic events stored under remote monitoring Results: 214 p were studied: 147 (68.7%) implanted with single chamber ICD and 67 (31.3%) with dual chamber ICD. Mean age was of 61.5 years, 14% were women, 79.9% were in NYHA class II or III, and majority were under optimal treatment (betablockers in 92.5%, ACEI or ARB antagonist in 89.6% and aldosterone antagonists in 61.3%). A few p suffered other comorbidities such as stroke, COPD and CKD (5.9%, 12.7% and 17.1% respectively), but previous AF was present in 33.2% of cases. Median QRS duration was 110 ms with only 18% of cases with QRS >130 ms During a mean follow up of 3.7 ± 2.2 years, 10.3% of p (n=22) presented an inappropriate ICD therapy most of them corresponded to fast rate AF (9 episodes). Moreover there were 5 episodes secondary to paroxysmal supraventricular tachycardia, 3 corresponded to non-sustained VT, 3 correspond to T wave oversensing and 2 were due to noise. Single chamber devices were more often implanted in p with hypertension, dyslipidemia, COPD, previous AF, previous HF admission and in those symptomatic (NYHA II or III) (p values < 0.05 for all comparisons). Programming was not different between subgroups of devices (table). All but one episode of inappropriate therapy occurred in single chamber ICD p. Despite the misbalance between single and chamber ICD p characteristics, after multivariable logistic regression covariate adjustment, dual chamber ICD effectively prevented from inappropriate ICD therapy (HR=0.091 [95% CI, 0.012-0.704] Conclusions: in narrow QRS HF patients undergoing ICD implant for primary prevention, without cardiac resynchronization, dual chamber devices are still useful in preventing from inappropriate therapies and their desirable consequences.