Equivalent arrhythmic risk in patients recently diagnosed with dilated cardiomyopathy compared with patients diagnosed for 9 months or more

BackgroundThe Centers for Medicare and Medicaid Services (CMS) recently expanded coverage for implantable cardioverter-defibrillators (ICDs) in patients with left ventricular ejection fraction ≤35% and nonischemic dilated cardiomyopathy for ≥9 months. To investigate the ramifications of these criteria, the ICD registry from Tufts-New England Medical Center was analyzed for arrhythmic events and death in patients with newly diagnosed (<9 months) vs late-diagnosed (≥9 months) nonischemic dilated cardiomyopathy.ObjectivesThe purpose of this study was to analyze the arrhythmic risk in patients with recent vs late diagnosis of nonischemic dilated cardiomyopathy.MethodsOne hundred thirty-one patients with nonischemic dilated cardiomyopathy were divided into two cohorts (<9 or ≥9 months of symptoms) and analyzed for any occurrence of treated ventricular arrhythmia, potentially lethal arrhythmias defined as ventricular flutter rates ≥230 bpm, and ventricular fibrillation. Patients with documented sustained ventricular tachycardias (included in prior CMS coverage) were excluded.ResultsIn the study group, the mean age was 58.1 ± 15 years and ejection fraction 20.6% ± 8%. In a follow-up period of 25.3 ± 24 months, the 52 patients with a recent diagnosis (1.4 ± 2 months) had no difference in the occurrence of ventricular arrhythmias (P = .49) and malignant ventricular arrhythmias (P = .16) compared with the 79 patients diagnosed ≥9 months (mean 58.1 ± 39 months).ConclusionPatients with nonischemic dilated cardiomyopathy experienced equivalent occurrences of treated and potentially lethal arrhythmias irrespective of diagnosis duration. These findings suggest that the 9-month time qualifier used in the CMS guidelines for ICD reimbursement may not reliably discriminate patients at high risk for sudden cardiac death in this selected population.