We sought to identify the electrocardiographic and electrophysiological characteristics of ventricular arrhythmias (VAs), including idiopathic ventricular tachycardia (VT) and premature ventricular contractions (PVCs), with acute successful radiofrequency catheter ablation (RFCA) at the superior portion of the mitral annulus (SP-MA). Among 437 consecutive patients who presented with VAs for RFCA, twenty-six patients with acute successful RFCA at the SP-MA were included in this study. The ratio of the amplitude of the first positive peak (if present) versus the nadir in the unipolar electrogram (EGM) was 0.00–0.03 (0.00) at the acute successful RFCA site. The time interval between the QRS onset and the maximum descending slope (D-Max) in the unipolar EGM (QRS-Uni) was 18.8 ± 13.6 ms. With bipolar mapping, the ventricular QRS (V-QRS) interval was 3.75–17.3 (11) ms, 6 (23.1%) patients showed the earliest V-QRS interval of 0 ms, and the other 20 patients (76.9%) showed a V-QRS interval of 10–54 ms. The RFCA start-to-effect time was 14.1 ± 7.2 s in 23 patients (88.5%). In the remaining 3 patients (11.5%), the mean duration of successful RFCA was not well defined due to the infrequent nature of clinical VAs during RFCA. Early (within 3 days) and late (1-year) recurrence rates were 23.1% (6 patients) and 26.9% (7 patients), respectively. VAs disappeared 3 days later due to delayed RFCA efficacy in 2 patients (7.7%). No complications occurred during the RFCA procedure or the one-year follow-up. SP-MA VAs are a rare but distinct subgroup of VAs. Bipolar and unipolar EGM features can help to determine the optimal RFCA site, and the QRS-Uni interval may serve as a marker that could be used to guide RFCA.

中文翻译：

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二尖瓣环上部急性成功消融的特发性室性心律失常的心电图和电生理特征

我们试图确定室性心律失常 (VA) 的心电图和电生理特征，包括特发性室性心动过速 (VT) 和室性早搏 (PVC)，并在二尖瓣环 (SP) 的上部进行急性成功射频导管消融 (RFCA) -嘛）。在 437 名因 RFCA 出现 VA 的连续患者中，26 名在 SP-MA 中急性成功 RFCA 的患者被纳入本研究。在急性成功 RFCA 部位，第一个正峰（如果存在）与单极电图 (EGM) 中最低点的幅度之比为 0.00–0.03 (0.00)。在单极 EGM (QRS-Uni) 中 QRS 开始和最大下降斜率 (D-Max) 之间的时间间隔为 18.8 ± 13.6 ms。使用双极标测时，心室 QRS (V-QRS) 间期为 3。75-17.3 (11) ms，6 名 (23.1%) 患者显示最早的 V-QRS 间期为 0 ms，其他 20 名患者 (76.9%) 显示 V-QRS 间期为 10-54 ms。23 名患者 (88.5%) 的 RFCA 开始生效时间为 14.1 ± 7.2 秒。在其余 3 名患者 (11.5%) 中，由于 RFCA 期间临床 VA 的不频繁性质，成功的 RFCA 的平均持续时间没有明确定义。早期（3 天内）和晚期（1 年）复发率分别为 23.1%（6 名患者）和 26.9%（7 名患者）。由于 2 名患者（7.7%）的 RFCA 疗效延迟，3 天后 VA 消失。在 RFCA 程序或一年的随访期间没有发生并发症。SP-MA VA 是一种罕见但独特的 VA 亚组。双极和单极 EGM 功能可以帮助确定最佳 RFCA 站点，