High-resolution imaging may get physicians closer to the areas that most need epicardial ablation when addressing ventricular tachycardia (VT). Real-time multidetector CT to assist with epicardial ablation proved useful for determining optimal ablation while avoiding coronary arteries and phrenic nerves.

This was particularly important in cases with nonischemic cardiomyopathy, where coronary arteries and phrenic nerves were very close to the epicardial substrate for VT (within 1 cm).

Seigo Yamashita, MD, PhD, of the Hôpital Cardiologique du Haut-Lévêque in Bordeaux-Pessac, France, and colleagues enrolled 95 consecutive patients with VT. Patients were assessed for local abnormal ventricular activities (LAVAs), which they found in 85 percent of patients. In 80 percent of patients, LAVAs were within 1 cm of coronary arteries; in 37 percent, within 1 cm of phrenic nerves. Patients with nonischemic cardiomyopathy had higher incidence of LAVAs near these structures.

Of the patients with LAVA, they achieved complete elimination of abnormal activity in 66 percent. Only 44 percent of patients with nonischemic cardiomyopathy achieved successful elimination of abnormal activity. Incomplete elimination of abnormal activity occurred due to proximity of coronary arteries and phrenic nerves in eight and fourpatients, respectively. However, successful elimination of abnormal activity in close proximity to coronary arteries and phrenic nerves occurred in 15 and three patients, respectively.

Yamashita et al noted that use of multidetector CT allowed them to get closer to arteries and nerves and reduce the risk of damaging these structures.

The study was published online Feb. 21 in Circulation: Arrhythmia and Electrophysiology.