Comprehensive assessment of unexplained sudden cardiac death and idiopathic ventricular fibrillation during the index hospitalization: A systematic thorough investigation to unmask specific etiology

Background The previous studies have shown that a systematic assessment, during the initial hospitalization after sudden cardiac death (SCD), provides the capacity to unmask specific etiology. The diagnosis of idiopathic ventricular fibrillation (IVF) is probably overestimated because of an unsystematic workup. Purpose We aimed to assess the profitability of comprehensive medical investigation strategy after SCD in a single university center. Methods Based on an implantable cardiac defibrillator data-base interrogation, the patients who survived from ventricular fibrillation without reversible cause were identified between 2012 and 2019. The etiological examinations performed during the initial hospitalization or planned after discharge were collected. Results In a cohort of 66 patients, retrospectively included, a minimal assessment including twelve-lead ECG, trans-thoracic echocardiography and coronary imaging allowed to unmask etiology for 40 (61%) patients. Ventricular fibrillation remained idiopathic for 16(24%) patients by adding magnetic resonance imaging, and for 12(18%) patients by performing provocative and genetic tests. Among the 54 patients for whom the diagnosis was confirmed, we reported 12(22%) electrical cardiac disorders, 11(20%) ischemic cardiopathy, 9(17%) dilated cardiomyopathy, 9(17%) valvular disease, 8(15%) hypertrophic cardiomyopathy, 4(7%) myocarditis and 1(2%) tako-tsubo syndrome. The number of examinations carried out in the IVF cohort did not differ from the others (6 vs. 5, P = 0.06). In the IVF group, SCD event occurred more frequently at rest (8/12 vs. 14/54, P = 0.02) and the patients were preferably women (9/12 vs. 13/54, P = 0.02). Conclusion Systematic etiologic investigations, carried out during initial assessment after SCD, allowed to unmask etiology for a large number of patients. Further studies are needed to standardize the workup to implement in all tertiary centers.