Arrhytmic event prediction in patients with heart failure and reduced ejection fraction

BackgroundImplantable cardioverter defibrillator (ICD) isan effective treatment to reduce mortality in patients withsymptomatic heart failure and left ventricular ejectionfraction (LVEF) 35% or less. LVEF presents a low sensitivityfor predicting arrhythmic events. Aim of this study was toidentify predictors of sustained ventricular arrhythmias(SVAs), overall and according to the cause of heart failure.MethodsSingle-center, retrospective, cohort study of 193patients (51 nonischemic and 142 ischemic) with chronicheart failure and LVEF less than 35% who had received ICDfor primary prevention of sudden cardiac death. Wecollected clinical data, echocardiographic parameters andSVAs detected by the ICD.ResultsDuring a median follow-up of 1440 days, 32 (16.2%)patients had SVAs. SVAs incidence was similar in patientswith nonischemic (15.6%) and ischemic cause of heartfailure (16.9%). Hypertension, diabetes, chronic renalfailure, atrial fibrillation, chronic obstructive pulmonarydisease, New York Heart Association class at least III werepredictors at univariate analysis of SVAs. A clinical score,assigning one point to each of these variables, wasassociated with a significantly increased risk of SVAs [oddsratio for each point increaseU1.92, 95% confidence interval1.40 – 2.65,P< 0.0001, area under the curve (AUC) 0.73],with 72% sensitivity and 60% specificity for a cutoff at leastthree and remained significant in nonischemic (AUC 0.84)and ischemic (AUC 0.68) patients.ConclusionOur study shows the benefit of ICDimplantation in primary prevention and its independency ofcause. A simple clinical score, based on comorbidities,identifies patients with more benefits from ICD implantation.