Smoking aggravates ventricular arrhythmic events in non-ischemic dilated cardiomyopathy associated with a late gadolinium enhancement in cardiac MRI

Smoking is known to increase cardiovascular events, but the association and mechanisms between smoking and ventricular arrhythmic events in dilated cardiomyopathy (DCMP) are unknown. The purpose of this study is to investigate the hypothesis that smoking is associated with sudden cardiac death (SCD) and ventricular arrhythmia in DCMP patients. We enrolled 378 patients who underwent cardiovascular magnetic resonance imaging (cMRI) and were diagnosed with DCMP at two general hospitals in Korea. The clinical data and left ventricular late-gadolinium enhancement (LV-LGE) of all patients were analyzed according to being never-smokers or smokers. Smokers were more likely to be male than never-smokers, but there was no other clinical difference between them. Smokers had a greater LV-LGE ratio, and multi-segment involvement of LV-LGEs. Smoking and a low left ventricular (LV) ejection fraction were significant predictors of the presence of LV-LGEs even after adjusting for optimal medical therapy. In addition, smokers had a higher fatal ventricular arrhythmic (FVA; sustained ventricular tachycardia, and ventricular fibrillation) and FVA + SCD, and ex-smokers had a similar FVA to never-smokers during 44.3 ± 36.4 months of follow-up. Finally, smoking independently increased the FVA + SCD even after adjusting for the clinical variables and LV-LGE. Smoking is associated with a multi-segmental involvement of LV-LGE and increased FVA + SCD in DCMP patients when compared to never-smokers.