Electrocardiographic versus echocardiographic left ventricular hypertrophy and sudden cardiac arrest in the community

Background Left ventricular hypertrophy (LVH) is associated with increased risk of sudden cardiac arrest (SCA). Whether LVH diagnosed by 12-lead ECG vs echocardiogram conveys identical or distinct risk information has not been previously evaluated. Objective The purpose of this study was to compare the association between ECG vs echocardiographic LVH and SCA in the community. Methods In a large, prospective population-based study (The Oregon Sudden Unexpected Death Study; population approximately 1 million), cases of SCA were compared to controls recruited from the same geographical area. The association between LVH and SCA was evaluated, specifically comparing LVH diagnosed by ECG vs echocardiogram. Results Cases (n = 132, age 66.9 ± 13.5 years, 58.3% male) compared to controls (n = 211; age 66.2 ± 12 years, 59.2% male) were more likely to have both ECG LVH (12.1% vs 5.7%, P =.03) and echocardiographic LVH (35.0% vs 15.5%, P <.001). However, there was poor agreement between the tests (kappa statistic = 0.128). A large subgroup of patients with ECG LVH (57.1%) did not have echocardiographic LVH; conversely, 83.6% of patients with echocardiographic LVH did not have ECG LVH. In multivariate analysis, ECG LVH was significantly associated with SCA (odds ratio [OR] 2.5, 95% confidence interval [CI] 1.1-6.0, P =.04). When echocardiographic LVH was added to the model, this association was only mildly attenuated (OR 2.4, 95% CI 1.0-6.0, P=.05), and echocardiographic LVH was also independently associated with SCA (OR 2.7, 95% CI 1.5-4.9, P =.001). Conclusion ECG and echocardiographic LVH may convey distinct risk information in patients with SCA, reflecting electrical vs anatomic remodeling. These findings have potential implications for SCA mechanisms and risk stratification.