Identifying ventricular tachycardia exit site utilising a coronary sinus lead pace map; a case report

Mapping of ventricular tachycardia (VT) can prove challenging secondary to scar complexity and potential multiple arrhythmia channels, including epicardial. Some mapping strategies include entrainment, local activation time, voltage and pacing maps. We describe an interesting case of an epicardial pace map utilising a coronary sinus (CS) lead inserted for cardiac resynchronisation therapy (CRT). A 69 year old male with ischaemic cardiomyopathy presented for CRT device upgrade. He also had recurrent shocks for ventricular tachycardia (VT) despite endocardial VT ablation and sympathectomy. During coronary sinus lead implantation, a paced complex morphology similar to the clinical VT was observed. Correspondingly, an epicardial ablation was undertaken to an area of very late activation on the basal infero-lateral wall, resulting in lack of inducibility.