Arrhythmias originating from the right ventricular outflow tract: how to distinguish "malignant" from "benign"?

Idiopathic ventricular tachycardia (VT) originating from the right ventricular outflow tract (RVOT) in patients without structural heart diseases is generally considered as a benign ventricular arrhythmia (VA). However, "malignant" VA, ventricular fibrillation (VF), and/or polymorphic VT are occasionally initiated by VT or ventricular premature contraction (VPC) originating from the RVOT. In this review article, previous reports describing the malignant form of idiopathic RVOT VT are reviewed, and it is discussed how to distinguish the malignant form from the "benign" form of idiopathic VT originating from the RVOT.