P1741Arrhythmic risk among ischemic and non-ischemic heart failure patients with narrow QRS: insigths from the umbrella registry

Abstract

Background: concerns about the efficacy of prophylactic ICD in heart failure (HF) patients (p)are still present especially in non-ischemic (N-I). We sought to assess whether the arrhythmic risk was different among ischemic (I) and N-I p with narrow QRS. Methods: HF p undergoing ICD-only implant were extracted from the nationwide multicenter UMBRELLA registry. Remote monitoring, reviewed by a committee of experts, was used to collect all the arrhythmic events. Results: 214 p (123 N-I; 91 I) were collected: mean age 61.5 years, 79.9% in NYHA class II or III, under treatment with betablockers in 92.5% and ACEI or ARB antagonist in 89.6% (without differences between groups). Mean QRS duration was of 112 ms with only a 18% of cases with QRS >130 ms. I p had higher burden of cardiovascular risk factors, while AF, CKD and COPD appeared more frequently in N-I. Arrhythmic event rate was 6.5% per year after 3.3 years of median follow-up. The majority of the tachycardia events responsible for the first ICD intervention were SMVT (76.5%); while the rest 23.5% were SPVT/VF events. Although a trend towards increasing prevalence of VF/SPVT episodes in I (36.4% vs 13.8% in N-I p) and SMVT in N-I p (86.2% Vs 63.6% in I p) appeared (p=0.06), mean tachycardia cycle length was similar (261.6653.7 ms vs 261638 ms for I and N-I respectively; p=0.461). High-energy shocks terminate majority of events (58%). First appropriate ICD therapy occurred in 51 p without differences between I and N-I groups (24.2% Vs 23.6% respectively, p=0.537). Adjusted Cox proportional hazard analysis confirmed a similar arrhythmic risk according to cardiomyopathy origin (HR=1.06 [95% CI, 0.59-1.90]; p=0.848). After multivariate Cox regression analysis, higher cut-off points (ms) for ventricular fibrillation zone (HR=1.02; p=0.042) and shorter detection windows (p=0.032) were independent predictors of appropriate therapy(NID 30/40 vs 18/24: HR=0.36, p=0.009) Conclusions: antiarrhythmic efficacy of ICD for primary prevention in HF patients with true narrow QRS is similar despite cardiomyopathy origin and other comorbidities. Furthermore, higher tachycardia therapy zone limit and longer detection windows should be programmed in this population. (Table Presented)