Ventricular arrhythmias in nonischemic cardiomyopathy: Overview

“Nonischemic cardiomyopathy (NICM)” is a myocardial disease which is characterized by ventricular dysfunction without significant coronary artery disease, including coronary spasms. Ventricular tachyarrhythmias are often observed in NICM, which lead to sudden cardiac death. Therefore, it is important to understand the anatomical and/or electrophysiological substrates in the different types of NICM. Because several new diagnostic approaches of cardiac MRI and/or genetic testing, and the specific management of antiarrhythmic drugs, catheter ablation, and defibrillators, have been available for some time, the risk stratification and specific management would change. In this special issue, we will summarize and overview the current understanding of each type of NICM, especially focusing on the risk stratification and specific management in the different types of NICM. In this first report, we selected arrhythmogenic right ventricular cardiomyopathy (ARVC), cardiac tumors, arrhythmia‐induced cardiomyopathy (AIC), and Takotsubo syndrome (TTS). We also gave an overview of the recent progress in the diagnosis/management of NICM, including advanced catheter ablation.