Background: The relationship between structural and electrical remodeling in the heart, particularly after long-standing endurance training, remains unclear. Signal-averaged electrocardiogram (SAECG) may provide a more sensitive method to evaluate cardiac remodeling than a 12-lead electrocardiogram (ECG). Accurate measures of electrical function (SAECG filtered QRS duration (fQRSd) and late potentials (LP) and left-ventricular mass (cardiac magnetic resonance, CMR) can allow an assessment of structural and electrical remodeling. Methods: Endurance athletes (45-65 years old, >10 years of endurance sport), screened to exclude cardiac disease, had standardized 12-lead ECG, SAECG, resting echocardiogram (ECHO), and CMR performed. SAECG fQRSd was correlated with QRS duration on the 12-lead ECG, and ECHO and CMR-derived left ventricular (LV) mass. Results: Participants (n=82, 67% male, mean age: 54±6 years, mean VO₂max: 50±7 ml/kg/min) had a CMR-derived LV mass of 118±28 g/m² and a fQRSd of 112±8 ms (46% had abnormal fQRSd (>114 msec), and 51% met clinical threshold for abnormal SAECG). fQRSd was positively correlated with the 12-lead ECG QRS duration (r=0.83), ECHO-derived LV mass (r=0.60), CMR-derived LV mass (r=0.58) and LV end-diastolic volume (r=0.63, p<0.001 for all). fQRSd had higher correlations with ECHO and CMR-derived LV mass than 12-lead ECG (p<0.0008 and p<0.0005, respectively). Conclusion: In a healthy cohort of middle-aged endurance athletes, the SAECG is often abnormal by conventional criteria, and is correlated with structural remodeling, but CMR evaluation does not indicate pathologic structural remodeling. SAECG fQRSd is superior to the 12-lead ECG for the electrocardiographic evaluation of LV mass.

中文翻译：

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中年耐力运动员的心脏重塑：信号平均心电图和左心室重量之间的关系

背景：心脏结构与电重构之间的关系，尤其是经过长期耐力训练后，尚不清楚。与12导联心电图（ECG）相比，信号平均心电图（SAECG）可以提供一种更敏感的方法来评估心脏重构。正确的电功能测量（SAECG滤波QRS持续时间（fQRSd）和晚期电势（LP）和左心室质量（心脏磁共振，CMR）可以评估结构和电重构方法：耐力运动员（45-65岁）年龄大于10岁的耐力运动），经过筛查以排除心脏病，并进行了标准化的12导联心电图，SAECG，静息超声心动图（ECHO）和CMR检查。回声和CMR衍生的左心室（LV）肿块。₂ max：50±7 ml / kg / min）的CMR衍生的LV质量为118±28 g / m ²fQRSd为112±8 ms（46％具有异常fQRSd（> 114毫秒），而51％符合SAECG异常的临床阈值）。fQRSd与12导联心电图QRS持续时间（r = 0.83），ECHO衍生的LV质量（r = 0.60），CMR衍生的LV质量（r = 0.58）和LV舒张末期体积（r = 0.63，对于所有p ＜0.001）。与12导联心电图相比，fQRSd与ECHO和CMR衍生的左心室质量相关性更高（分别为p <0.0008和p <0.0005）。结论：在健康的中年耐力运动员队列中，按照常规标准，SAECG通常是异常的，并且与结构重塑有关，但CMR评估并未提示病理结构重塑。SAECG fQRSd在心电图评估左心室质量方面优于12导联心电图。