Electrocardiographic and echocardiographic predictors of greater carotid intima-media thickness in tactical athletes: The CHIEF atherosclerosis study

Objective: Both electrocardiographic and echocardiographic left ventricular hypertrophy (LVH) have been reported with an association with greater carotid intima-media thickness (cIMT), a marker of subclinical atherosclerosis in patients with hypertension, while the associations are unclear in physically fit young adults. Methods: A total of 1822 Taiwanese military personnel, aged 18–40 years, received an annual health examination including electrocardiography (ECG) and echocardiography in 2018–2020. Left carotid bulb cIMT was measured by high-resolution ultrasonography. Multiple logistic regression analysis with adjustments for age, sex, smoking, alcohol consumption, body mass index, mean blood pressure, and physical fitness was used to determine the associations between echocardiographic and ECG parameters and the highest quintile of cIMT (≥0.8 mm). Results: Cornell-based LVH, Myers et al.-based RVH and heart rate ≥75/min were associated with cIMT ≥0.8 mm [odds ratios (ORs) and 95% confidence intervals: 1.54 (1.01, 2.35), 1.66 (1.18, 2.33), and 1.39 (1.06, 1.83), respectively], while echocardiographic LVH defined as ≥46.0 g/m^2.7 for men and ≥38.0 g/m^2.7 for women was inversely associated with cIMT ≥0.8 mm [OR: 0.45 (0.24, 0.86)]. Conclusion: In tactical athletes of military, the associations of ECG and echocardiographic LVH with cIMT were in opposite directions. Higher physical fitness may cause cardiac muscle hypertrophy and reduce the atherosclerosis severity, possibly leading to the paradoxical echocardiographic finding. This study suggests that ECG-based LVH remains a good marker of subclinical atherosclerosis in our military population.