How to use the 12-lead ECG to predict the site of origin of idiopathic ventricular arrhythmias

Idiopathic ventricular arrhythmias may arise from anywhere in the heart, and the majority of them can be effectively treated with catheter ablation. The 12-lead electrocardiogram (ECG) is the initial mapping tool to predict the most likely site of origin and is valuable to choose the appropriate ablation strategy. Crucial to ECG interpretation is understanding the attitudinal orientation of the heart within the chest and the relationship between the different cardiac structures. In this review, we provide a stepwise anatomical approach for the localization of idiopathic ventricular arrhythmias based on sequential analysis of the most relevant ECG features.