Ventricular far-field activity may provide a diagnostic challenge in identifying an origin of ventricular tachycardia arising from the left ventricular papillary muscle.

A 57-year-old man with idiopathic ventricular tachycardia (VT) underwent electrophysiological testing. Activation mapping revealed two remote earliest ventricular activation sites on anterior and posterior sides of the anterior papillary muscle. On the anterior side, far-field activity preceded near-field activity. Catheter ablation was successful on the posterior side. Ventricular far-field activity may provide diagnostic challenges in identifying papillary muscle VT origins.