Survival, ventricular arrhythmia, and implantable cardioverter-defibrillator usefulness in toxic cardiomyopathy due to substance abuse.

Abstract

Toxic dilated cardiomyopathy (T-DCM) due to substance abuse is now recognized as a potential cause of severe left ventricular dysfunction. The burden of ventricular arrhythmias (VA) and the role of a prophylactic implantable cardioverter-defibrillator (ICD) are not well documented in this population. We aim to assess the usefulness of ICD implantation in a T-DCM cohort. Patients younger than 65 years with a left ventricular ejection fraction (LVEF)<35% followed at a tertiary center heart failure (HF) clinic between January 2003 and August 2019 were screened for inclusion. The diagnosis of T-DCM was confirmed after excluding other etiologies, and substance abuse was established according to the DSM-5 criteria. The composite primary endpoints were arrhythmic syncope, sudden cardiac death (SCD), or death of unknown cause. The secondary endpoints were the occurrence of sustained VA and/or appropriate therapies in ICD carriers. Thirty-eight patients were identified, and an ICD was implanted in 19 (50%) of these patients, only one for secondary prevention. The primary outcome was similar between the two groups (ICD vs. non-ICD; p=1.00). After a mean follow-up of 33±36 months, only two VA episodes were reported in the ICD group. Three patients received inappropriate ICD therapies. One ICD implantation was complicated with cardiac tamponade. Twenty-three patients (61%) had an LVEF ≥35% at 12 months. VA are infrequent in the T-DCM population. The prophylactic ICD benefit was not observed in our cohort. The ideal timing for potential prophylactic ICD implantation in this population needs further studies.