Electrocardiographic characteristics of ventricular arrhythmias originating from the junction of the left and right coronary sinuses of Valsalva in the aorta: The activation pattern as a rationale for the electrocardiographic characteristics

BackgroundVentricular arrhythmias (VAs) may arise from the aortic sinuses and have electrocardiographic and electrophysiological characteristics that suggest a left (LCC) or right coronary cusp (RCC) origin. However, VAs that arise near the junction of those two cusps (L-RCC) may have unusual features.ObjectivesThe purpose of this study was to examine the electrocardiographic and electrophysiological characteristics of VAs arising from the L-RCC.MethodsWe studied 155 patients with idiopathic VAs with either left or right bundle branch block and an inferior QRS axis morphology and five control subjects undergoing a pacing study.ResultsFor 146 of the 155 patients, the origin determined by the successful ablation site was at the L-RCC in five, LCC in 13, RCC in six, non–coronary cusp in two, right ventricular outflow tract in 108, left ventricular outflow tract in five, left ventricular epicardium in four, and pulmonary artery in three. A qrS pattern in leads V1–V3 was observed only in the VAs with an L-RCC origin. The propagation map revealed that the direction of the propagating wave front from the L-RCC origin produced a vector compatible with a q wave and that the anterior activation to the right ventricular outflow tract via the LCC or RCC formed the r wave. Pacing performed at multiple sites in the aortic root in the control subjects demonstrated that only pacing from the L-RCC could reproduce a qrS pattern in leads V1–V3.ConclusionsThis study revealed that a qrS pattern in leads V1–V3 suggests a site of origin at the L-RCC.