Vera-Sarmiento Hernan L, Tanriverdi Talha, Hurtado-de-Mendoza David, Sivalokanathan Sanjay, Damera Ramses Ramirez, Ketty Dolores, Lu Daiyin, Zimmerman Stefan, Sinha Sunil, Scheinman Melvin, Abraham M Roselle
Hypertrophic Cardiomyopathy Center of Excellence, Division of Cardiology, University of California San Francisco, San Francisco, CA, United States of America.
Hypertrophic Cardiomyopathy Center of Excellence, Division of Cardiology, University of California San Francisco, San Francisco, CA, United States of America; Department of Medicine, SUNY Upstate Medical University, Syracuse, NY, United States of America.
J Electrocardiol. 2024 Nov-Dec;87:153818. doi: 10.1016/j.jelectrocard.2024.153818. Epub 2024 Oct 22.
Signal-averaged electrocardiogram (SAECG) records myocardial depolarization, and can detect inhomogeneous/slow conduction in fibrotic myocardium, which promotes reentrant ventricular arrhythmias (VAs). Hypertrophic cardiomyopathy (HCM) is associated with a high prevalence of cardiac fibrosis and VAs, but abnormal SAECG has low predictive power for VAs. We hypothesized that HCM-specific structural/electrical remodeling underlies this result.
We tested our hypothesis by retrospectively studying HCM patients (n = 73) who underwent transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR) imaging within 12 months of SAECG and 12‑lead ECG. Patients were divided into 2 groups (normal-SAECG, abnormal-SAECG) based on filtered-QRS duration (fQRSd), root-mean-square-voltage (RMS40) and low-amplitude (<40 μV) signal of terminal 40 ms of filtered-QRS (late potentials). Abnormal SAECG was defined as fQRSd > 114 ms, RMS40 < 20 μV or LAS40 > 38 ms.
Abnormal SAECG was seen in ∼50 % of HCM patients (37/73). In the abnormal-SAECG group, 78 % (n = 29) only had prolonged fQRSd, and 22 % (n = 8) had prolonged fQRSd plus late potentials (RMS40 < 20 μV or LAS40 > 38 ms). Mean fQRSd and LAS40 were significantly higher in the abnormal-SAECG group. The abnormal-SAECG group had significantly larger LA size, lower global-LV longitudinal systolic strain/strain rate and early-diastolic strain rate by TTE; higher LV-mass index (LVMI) and LV-scar burden by CMR; higher prevalence of repolarization abnormalities on 12‑lead ECG. LVEF and adverse outcomes (VT/VF, heart failure, death) were similar in the 2 groups. Univariate analysis showed that fQRSd is positively correlated with LVMI, LV-scar mass, and negatively correlated with global-LV early diastolic strain rate.
In HCM, abnormal SAECG is associated with greater structural/electrical LV-remodeling, reflecting a severe global myopathy.
信号平均心电图（SAECG）记录心肌去极化，可检测纤维化心肌中的不均匀/缓慢传导，这会促进折返性室性心律失常（VA）。肥厚型心肌病（HCM）与心脏纤维化和VA的高患病率相关，但异常SAECG对VA的预测能力较低。我们推测HCM特异性的结构/电重构是导致这一结果的原因。
我们通过回顾性研究73例HCM患者来验证我们的假设，这些患者在进行SAECG和12导联心电图检查的12个月内接受了经胸超声心动图（TTE）和心脏磁共振（CMR）成像检查。根据滤波QRS波时限（fQRSd）、均方根电压（RMS40）和滤波QRS波终末40ms的低振幅（<40μV）信号（晚电位），将患者分为两组（正常SAECG组、异常SAECG组）。异常SAECG定义为fQRSd>114ms、RMS40<20μV或LAS40>38ms。
约50%的HCM患者（37/73）出现异常SAECG。在异常SAECG组中，78%（n=29）仅fQRSd延长，22%（n=8）fQRSd延长并伴有晚电位（RMS40<20μV或LAS40>38ms）。异常SAECG组的平均fQRSd和LAS40显著更高。异常SAECG组的左心房大小显著更大，TTE显示的整体左心室纵向收缩应变/应变率和舒张早期应变率更低；CMR显示的左心室质量指数（LVMI）和左心室瘢痕负荷更高；12导联心电图上复极异常的患病率更高。两组的左心室射血分数（LVEF）和不良结局（室性心动过速/心室颤动、心力衰竭、死亡）相似。单因素分析显示，fQRSd与LVMI、左心室瘢痕质量呈正相关，与整体左心室舒张早期应变率呈负相关。
在HCM中，异常SAECG与更严重的左心室结构/电重构相关，反映了严重的全身性心肌病。
