A case of premature ventricular contractions originating from the papillary muscle in the right ventricle

A 45-year-old man with premature ventricular contractions (PVCs) underwent electrophysiological studies. Activation mapping using a noncontact electroanatomical mapping system indicated that the septal mid-apical region in the right ventricle was activated earliest. However, pace mapping did not match the activation mapping. Although the PVCs were successfully eliminated by applying radiofrequency current to the prepotential site preceding their QRS onset, a recurrence of PVCs with the same QRS morphology was observed at the 2-month follow-up examination, necessitating a second procedure. During the second procedure, echocardiography-guided electroanatomic mapping revealed centrifugal activation from the right ventricular mid-apical region on the septal portion of the anterior papillary muscle, but perfect pace mapping was not obtained at that site. With intracardiac echocardiography confirming good contact between the ablation catheter and papillary muscle, an irrigated radiofrequency current successfully eliminated the PVCs. This case indicates that the use of a guidance system may be feasible and useful for catheter ablation of PVCs originating from the right ventricular papillary muscle when there are discrepancies between activation mapping and pace mapping.