Background: The increased risk associated with left ventricular hypertrophy (LVH) diagnosed echocardiographically (Echo-LVH) or electrocardiographically (ECG-LVH) is well known, but the clinically relevant question of how much additional prognostic information would be provided by echocardiographically assessing LVH if a subject's ECG-LVH and hypertension status are known has not been addressed.
Methods and results: We investigated whether Echo-LVH and ECG-LVH predicted total and cardiovascular mortality and morbidity independently of each other and of other cardiovascular risk factors by using a population-based sample of 475 men investigated at age 70 with a median follow-up time of 5.2 years. Echocardiographic left ventricular mass index (LVMI) predicted total mortality (hazards ratio [HR] 1.44, 95% CI 1.09 to 1.92, for a 1-SD increase in LVMI) and cardiovascular mortality (HR 2.38, 95% CI 1.52 to 3.73) independently of ECG-LVH and other cardiovascular risk factors. ECG-LVH, defined as Cornell product >244 microV. s, predicted total mortality (HR 2.89, 95% CI 1.41 to 5.96) independently of LVMI and other cardiovascular risk factors. Thus, Echo-LVH and ECG-LVH provided complementary prognostic information, especially in hypertensive subjects.
Conclusions: Echo-LVH and ECG-LVH predict mortality independently of each other and of other cardiovascular risk factors, implying that Echo-LVH and ECG-LVH in part carry different prognostic information. Therefore, to fully assess the increased risk associated with these conditions, both ECG and echocardiography should be performed.