Inadvertent right ventricular apical exit after stereotactic body radiotherapy for ventricular tachycardia: Every cloud has a silver lining

A 78-year-old man suffering from gastric cancer with ischemic cardiomyopathy and recurrent ICD shocks consented to ventricular tachycardia (VT) ablation. He had a previous endocardial VT ablation 1 year ago, and a stereotactic radioablation for his recurrent VT 4 months ago. We planned again left ventricular endocardial mapping for his incessant slow VT suggesting an apical exit site (Figure 1A). However, the activation mapping of LV did not cover the whole VT cycle length, and we decide to map the right ventricular septal side instead of the epicardial access due to the patient's poor frailty. Fortunately, the mid-diastolic potential (MDP) was acquired in an unusual position (Figures 1A and 1B); however, the pericardial location of the mapping catheter was confirmed fluoroscopically (Figures 1C and 1D). An urgent surgical consultation was called for, and operative preparations were initiated. However, since no pericardial tamponade occurred and blood pressure remained stable, we continued the endo-epicardial ablation by ablating the MDP (Video 1).