Pearman Charles Michael, Walia Jagdeep, Alqarawi Wael, Larsen Jacob Moesgaard, Leach Emma, Krahn Andrew D, Laksman Zachary
Center for Cardiovascular Innovation, Heart Rhythm Services, Division of Cardiology, Department of Medicine, University of British Columbia, Vancouver, Canada.
Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.
Pacing Clin Electrophysiol. 2021 Dec;44(12):2046-2053. doi: 10.1111/pace.14379. Epub 2021 Oct 26.
Late potentials (LPs) identified on the signal averaged electrocardiogram (SAECG) are a marker for an increased risk of arrhythmias in Brugada syndrome (BrS). Procainamide is a sodium channel blocker used to diagnose BrS. The effects of Procainamide on the SAECG in those with BrS and the significance of Procainamide-induced LPs are unknown.
Procainamide provocation was performed for suspected BrS with 12-lead and SAECG pre- and post-infusion. Filtered QRS duration (fQRSd), duration of low amplitude signals <40 μV (LAS40) and root-mean-square voltage in the terminal 40 ms (RMS40) were determined.
Data from 150 patients were included in the analysis (mean age 44.5 years, 109 males). Procainamide increased fQRSd (Pre 118.8 ± 10.5 ms, post 121.2 ± 10.2 ms, p < 0.001) and LAS40 (Pre 38.7 ± 9.8 ms, post 40.2 ± 10.5 ms, p = 0.005) and decreased RMS40 (Pre 24.6 ± 12 ms, post 22.8 ± 12 ms, p = 0.002). LPs were present in 68/150 (45%) at baseline. Fifteen patients with negative baseline SAECGs had LPs unmasked by Procainamide, but six patients had LPs at baseline that were no longer present following Procainamide. Comparing those with normal hearts (n = 48) to those with a final diagnosis of BrS (n = 38), Procainamide prolonged fQRSd to a greater extent in those with BrS. Comparing those with Procainamide-induced LPs to those with no LPs at any time did not highlight any aspect of phenotype and did not correlate with a history of ventricular arrhythmias.
Procainamide influences the SAECG, provoking LPs in a small proportion of patients. However, there is no evidence that Procainamide-induced LPs provide additional diagnostic information or aid risk stratification.
信号平均心电图（SAECG）上识别出的晚电位（LPs）是 Brugada 综合征（BrS）中心律失常风险增加的一个标志物。普鲁卡因胺是一种用于诊断 BrS 的钠通道阻滞剂。普鲁卡因胺对 BrS 患者 SAECG 的影响以及普鲁卡因胺诱导的 LPs 的意义尚不清楚。
对疑似 BrS 患者进行普鲁卡因胺激发试验，在输注前和输注后记录 12 导联心电图和 SAECG。测定滤波后的 QRS 波时限（fQRSd）、低振幅信号<40μV 的时限（LAS40）以及终末 40ms 的均方根电压（RMS40）。
150 例患者的数据纳入分析（平均年龄 44.5 岁，男性 109 例）。普鲁卡因胺使 fQRSd 增加（术前 118.8±10.5ms，术后 121.2±10.2ms，p<0.001），LAS40 增加（术前 38.7±9.8ms，术后 40.2±10.5ms，p = 0.005），RMS40 降低（术前 24.6±12ms，术后 22.8±12ms，p = 0.002）。基线时 68/150（45%）存在 LPs。15 例基线 SAECG 阴性的患者经普鲁卡因胺激发后出现 LPs，但 6 例患者基线时存在 LPs，经普鲁卡因胺激发后不再出现。将正常心脏患者（n = 48）与最终诊断为 BrS 的患者（n = 38）进行比较，普鲁卡因胺使 BrS 患者的 fQRSd 延长程度更大。将有普鲁卡因胺诱导的 LPs 的患者与任何时候都无 LPs 的患者进行比较，未发现表型的任何方面有差异，也与室性心律失常病史无关。
普鲁卡因胺影响 SAECG，在一小部分患者中诱发 LPs。然而，没有证据表明普鲁卡因胺诱导的 LPs 能提供额外的诊断信息或有助于危险分层。
