Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada.
Department of Medicine, Division of Cardiology, St Michael's Hospital, University of Toronto, Toronto, Ontario, Canada.
Am J Physiol Heart Circ Physiol. 2021 Jan 1;320(1):H316-H322. doi: 10.1152/ajpheart.00602.2020. Epub 2020 Oct 30.
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 (LV) mass (cardiac magnetic resonance, CMR) can allow an assessment of structural remodeling and QRS prolongation. Endurance athletes (45-65 yr old, >10 yr 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 LV mass. Participants ( = 82, 67% male, mean age: 54 ± 6 yr, mean V̇o: 50 ± 7 mL/kg/min) had a CMR-derived LV mass of 118 ± 28 g/m and a fQRSd of 112 ± 8 ms (46% had abnormal fQRSd (>114 ms), and 51% met clinical threshold for abnormal SAECG). fQRSd was positively correlated with the 12-lead ECG QRS duration ( = 0.83), ECHO-derived LV mass ( = 0.60), CMR-derived LV mass ( = 0.58) and LV end-diastolic volume ( = 0.63, < 0.001 for all). fQRSd had higher correlations with ECHO and CMR-derived LV mass than 12-lead ECG ( < 0.0008 and < 0.0005, respectively). In 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. Study findings indicate that a positive correlation exists between electrical (SAECG fQRSd) and structural indices (LV mass) in middle-aged endurance athletes with normal physiological LV adaptation, in the absence of known cardiac pathology. SAECG fQRSd may also provide an alternative, superior method for identifying increased LV mass compared to other 12-lead ECG criteria.
心脏的结构和电重构之间的关系，尤其是在长期耐力训练之后，仍不清楚。信号平均心电图（SAECG）可能比 12 导联心电图（ECG）更能提供敏感的方法来评估心脏重构。准确的电功能测量（SAECG 滤波 QRS 持续时间（fQRSd）和晚期电位（LP）和左心室（LV）质量（心脏磁共振，CMR）可以评估结构重构和 QRS 延长。筛选出无心脏病的耐力运动员（45-65 岁，>10 年耐力运动）进行了标准的 12 导联心电图、SAECG、静息超声心动图（ECHO）和 CMR 检查。SAECG fQRSd 与 12 导联心电图上的 QRS 持续时间、ECHO 和 CMR 衍生的 LV 质量相关。参与者（=82，67%男性，平均年龄：54±6 岁，平均 V̇o：50±7 mL/kg/min）的 CMR 衍生的 LV 质量为 118±28 g/m，fQRSd 为 112±8 ms（46%的 fQRSd 异常（>114 ms），51%符合异常 SAECG 的临床阈值）。fQRSd 与 12 导联心电图的 QRS 持续时间（=0.83）、ECHO 衍生的 LV 质量（=0.60）、CMR 衍生的 LV 质量（=0.58）和 LV 舒张末期容积（=0.63，<0.001）呈正相关。fQRSd 与 ECHO 和 CMR 衍生的 LV 质量的相关性高于 12 导联心电图（分别为<0.0008 和<0.0005）。结论，在中年耐力运动员的健康队列中，SAECG 通常按照常规标准是异常的，与结构重构相关，但 CMR 评估并不表明存在病理性结构重构。SAECG fQRSd 优于 12 导联心电图用于 LV 质量的心电图评估。研究结果表明，在没有已知心脏病理学的情况下，具有正常生理 LV 适应性的中年耐力运动员中，电（SAECG fQRSd）和结构指数（LV 质量）之间存在正相关。与其他 12 导联心电图标准相比，SAECG fQRSd 也可能提供一种替代的、优越的方法来识别增加的 LV 质量。
