Reappraisal and New Observations on Idiopathic Ventricular Arrhythmias Ablated From the Noncoronary Aortic Sinus

The electrophysiological characteristics of idiopathic ventricular arrhythmias (VAs) from the noncoronary sinus (NCS) have not been fully described.

This study sought to investigate electrophysiological characteristics and catheter ablation in patients with idiopathic NCS-VA.

This study comprised 11 patients undergoing radiofrequency (RF) catheter ablation for idiopathic NCS-VA. Angiography was performed to confirm the origin in the aortic sinus before RF ablation.

Clinical arrhythmias presented left bundle block/inferior axis morphology in all patients. QRS morphology of R' and R/s' pattern was dominantly found in lead III. Mapping in the right ventricle demonstrated the earliest ventricular activation (EVA) site at the His Bundle region, whereas mapping in the NCS demonstrated that the EVA preceded the activation at the His Bundle region by 12.1 ± 7.9 milliseconds. All VAs were successfully ablated in <2.5 seconds within the NCS with 1 RF application. The successful ablation site was at the nadir of NCS in 10 patients, and near the junction of NCS and the right coronary sinus in the remaining one. A discrete potential can be observed at the EVA site within the NCS in 10 patients (91%); however, an excellent pace mapping at the EVA site was obtained in only 2 patients. Junctional beats did not occur during RF application in all 11 patients. There were no complications or clinical recurrence during a mean follow-up of 26.0 ± 9.8 months.

NCS-VA presents a peculiar electrocardiogram. A discrete potential can be mapped within the NCS during VA and sinus rhythm, and can be used in guiding ablation.