Ventricular arrhythmias ablated successfully in the subvalvular interleaflet triangle between the right and left coronary cusps: Electrophysiological characteristics and catheter ablation

BACKGROUND Ventricular arrhythmias (VAs) ablated successfully at the right-left subvalvular interleaflet triangle (R-L ILT) between right and left coronary cusps have not been fully characterized.OBJECTIVE The purpose of this study was to investigate the electrophysiological characteristics of these VAs and their relationships with the left ventricular (LV) summit.METHODS Twenty-eight VAs ablated successfully at the R-L ILT were studied.RESULTS Ninety-six percent of VAs had an early precordial electrocardiographic transition. R-wave amplitude in lead V-1 was relatively high (RS morphology, R-wave amplitude 0.35 +/- 0.09 mV; R/S ratio 0.35 +/- 0.27), whereas the morphology of lead I was R-shaped in 71% and M-shaped in 50% of VAs. Earliest potential was recorded at the R-L ILT in 13 of 28 patients and the left pulmonary sinus cusp (LC) in 6 of 28 patients. Mapping the summit communicating vein (summit-CV) failed because of anatomic or instrumental limitations in these 19 patients. In the other 9 patients, earliest potential was successfully recorded at the summit-CV, while perfect pacemapping was achieved. Poor pace mapping was achieved at the R-L ILT or LC in most patients (27/28). Target site was located at the top of the R-L ILT in all cases. A presystolic potential was present at the target site in 18 of 28 patients. A U-curve via the retrograde method was conventionally used to reach the top of the R-L ILT.CONCLUSION VAs ablated successfully at the R-L ILT have unique electrophysiological characteristics, and R-L ILT may be an endocardial anatomic ablation target for VAs originating from the base of the LV summit.

背景 在右冠状动脉窦和左冠状动脉窦之间的左右瓣下叶间三角（R - L ILT）处成功消融的室性心律失常（VAs）尚未得到充分描述。 目的 本研究旨在探讨这些室性心律失常的电生理特征及其与左心室（LV）顶部的关系。 方法 对在R - L ILT处成功消融的28例室性心律失常进行了研究。 结果 96%的室性心律失常胸前导联心电图有早期移行。V₁导联R波振幅相对较高（RS形态，R波振幅为0.35 ± 0.09 mV；R/S比值为0.35 ± 0.27），而71%的室性心律失常I导联形态为R型，50%为M型。28例患者中有13例在R - L ILT记录到最早电位，28例中有6例在左肺动脉窦瓣（LC）记录到最早电位。由于解剖或器械限制，这19例患者的顶部交通静脉（summit - CV）标测失败。在其他9例患者中，在顶部交通静脉成功记录到最早电位，同时实现了完美的起搏标测。大多数患者（27/28）在R - L ILT或LC处起搏标测不佳。所有病例的靶点均位于R - L ILT顶部。28例患者中有18例在靶点处存在收缩前期电位。通常采用逆行法的U形曲线到达R - L ILT顶部。 结论 在R - L ILT处成功消融的室性心律失常具有独特的电生理特征，R - L ILT可能是起源于左心室顶部基底部的室性心律失常的心内膜解剖消融靶点。