Transcoronary Mapping with an Over-the-wire Multielectrode Catheter in Scar-related Ventricular Tachycardia Patients

Background and Aims The usefulness of coronary venous system mapping has been reported for assessing intramural and epicardial substrates in patients with scar-related ventricular tachycardia (VT). However, there has been little data on mapping from coronary arteries. We investigated the safety and utility of mapping from coronary arteries with a novel over-the-wire multielectrode catheter in scar-related VT patients. Methods Ten consecutive scar-related VT patients with nonischemic cardiomyopathy who underwent mapping from a coronary artery were analyzed. Six patients underwent simultaneous coronary venous mapping. High-density maps were created by combining the left ventricular endocardium and coronary vessels. Results Substrate maps were created during the baseline rhythm with 2,438 points (IQR 2,136–3,490 points), including 329 (IQR 59-508 points) in coronary arteries. Abnormal bipolar electrograms were successfully recorded within coronary arteries close to the endocardial substrate in 7 patients. During VT, isthmus components were recorded within coronary vessels in 3 patients with no discernible isthmus components on endocardial mapping. The ablation terminated the VT from an endocardial site opposite the earliest site in the coronary arteries in 5 patients. Conclusions The transcoronary mapping with an over-the-wire multielectrode catheter can safely record abnormal bipolar electrograms within coronary arteries. Additional mapping data from coronary vessels have the potential to assess three-dimensional ventricular substrates and circuit structures in scar-related VT patients.