Combined Echocardiographic Left Ventricular Hypertrophy and Electrocardiographic ST Depression Improve Prediction of Mortality in American Indians

Abstract

Echocardiographic left ventricular hypertrophy (Echo-LVH) and ST segment depression (STD) on the ECG have each been demonstrated to predict cardiovascular (CV) and all-cause (AC) mortality. However, the prognostic value of combining Echo-LVH and ECG-STD has not been examined. ECGs and echocardiograms were examined in 2193 American Indian participants in the second Strong Heart Study examination. STD was measured by computer and was considered abnormal if ≥50 μV. Echo-LVH was defined by indexed LV mass >116 g/m ² in men and >104 g/m ² in women. After a mean follow-up of 3.1±0.7 years, there were 57 CV and 169 AC deaths. In univariate Cox analyses, Echo-LVH (χ ² =54.2 and χ ² =68.5) and ECG-STD (χ ² =35.9 and χ ² =46.3, all P 2 =74.4, P 2 =102.0, P 2 =19.7, P 2 =24.9, P <0.001), with the presence of both Echo-LVH and ECG-STD associated with a 6.3-fold increased risk of CV death (95% CI: 2.8 to 14.2) and a 4.6-fold increased risk of AC mortality (95% CI: 2.5 to 8.5). ECG-STD and Echo-LVH additively increase the risk of both CV mortality and AC mortality. These findings support the value of combining Echo-LVH and ECG-STD to improve risk stratification. These findings require verification in other populations.