Abstract 15759: Arrhythmic Risk Stratification in Patients With Idiopathic Dilated Cardiomyopathy and No Conventional Indications for Implantable Cardiac Defibrillator

Abstract

Background: Primary prevention of major ventricular arrhythmias (MVA) in patients with idiopathic dilated cardiomyopathy (IDCM) is primarily based on left ventricular ejection fraction (LVEF) assessment. Nonetheless, unexpected MVA still affect patients considered at low-risk (LR), attesting the limitation of the current risk stratification. We sought to identify the clinical predictors of MVA in patients with IDCM and no conventional indications for implantable cardioverter defibrillator (ICD). Methods: In this retrospective, case-control study, among 922 patients enrolled in the Heart Muscle Disease Registry of Trieste from 1988 to 2013, we analyzed 414 IDCM patients considered at LR according to the following criteria: LVEF≥36% and no previous episodes of MVA (sustained ventricular tachycardia/non-fatal ventricular fibrillation (SVT/VF), appropriate ICD intervention and sudden cardiac death (SD)). Data were recorded at the last available medical examination before the index event. Patients were optimally treated at the time of index evaluation (87% and 84% of ACE-inhibitors/sartans and beta-blockers, respectively). Results: Over a median follow-up of 43 (IQR 16-116) months, 45 patients (11 % of patients at LR; 31% of the all MVA in whole IDCM population) experienced MVA. The mean age at the time of event was 51±14 years. They were characterized by a previous history of syncope in 10 patients (22%), LVEF of 42±6% with a normal value (>50%) in 10 patients (22%), significant LV dilation (VTDi>90ml/m 2 ) in 16 patients (35%) and left bundle branch block 12 patients (27%). Independent risk factors for MVA in LR subgroup were previous history of syncope (OR 3.41, 1.45-8.03, p=0.004), larger left ventricular dilation (OR 2.62, 1.72-3.99, p<0.0001) and longer duration of disease (OR 1.39, 1.42-2.63, p<0.0001). Conclusions: in a large cohort of IDCM patients nearly one-third of the MVA occurred in a population apparently at LR of events. History of syncope, larger LV dilatation and significant duration of disease emerged as strong predictors of MVA and should be considered in the arrhythmic risk stratification of patients without conventional criteria for SD primary protection.