Prognostic implications of left ventricular hypertrophy diagnosed on electrocardiogram vs echocardiography

It is unclear whether 12-lead ECG employing standard criteria for left ventricular hypertrophy (LVH) provides similar information with respect to long-term cardiovascular risk as echocardiography. The authors performed a retrospective cohort study of 1376 individuals without cardiovascular disease, who underwent ECG (LVH defined using the Sokolow-Lyon voltage combination (>35 mm) or the Cornell voltage-duration product (>2440 mm × ms)) and echocardiography (LVH defined as LV mass index (LVMI) >95 g/m² for women and >115 g/m² for men). The prognostic ability of LVH was assessed in Cox regression models adjusted for age, sex, smoking, systolic blood pressure, total cholesterol, antihypertensive medication, and fasting glucose. The primary end point was the composite of coronary events, heart failure, stroke, or death. The main secondary end point was heart failure or cardiovascular death. Median age was 67 (range 56-79) years, 68% were male. Eleven percent had ECG-defined LVH, 17% had echocardiographic LVH. Over median 8.5 years, 29% experienced a primary event. Event rates were 29%/35% for persons without/with ECG-defined LVH and 27%/39% for those without/with echocardiographic LVH. The Sokolow-Lyon combination, Cornell product, and ECG-defined LVH did not significantly predict the primary end point (P ≥ .05), but ECG-defined LVH predicted heart failure or cardiovascular death (adjusted hazard ratio (HR), 1.86, 95% confidence interval (CI), 1.13-3.08); P = .02). Conversely, LVMI was a significant, independent predictor of the primary end point (adjusted HR, 1.87, 95% CI, 1.13-3.10; P = .01), as was echocardiographic LVH (adjusted HR, 1.27, 95% CI, 1.01-1.61; P = .04). Echocardiographic LVH may be a better predictor of long-term cardiovascular risk than ECG-defined LVH in middle-aged and older individuals.