Improved cardiovascular risk stratification by a simple ECG index in hypertension

BACKGROUND: We determined the prognostic value of the Cornell/strain [C/S] index, a simple electrocardiographic (ECG) index for left ventricular hypertrophy (LVH) defined by the presence of either a classic strain pattern or a Cornell voltage (sum of R in aVL + S in V(3)) >2.0 mV in women or 2.4 mV in men, or both. METHODS: In a prospective, cohort study, 2190 initially untreated subjects (age 51 [+/- 12], 47% women) with essential hypertension without prior events were followed for up to 14 years (median, 5 years). RESULTS: Prevalence of LVH at entry was 16.3% by using the C/S index, which yielded 33.6% sensitivity and 91.0% specificity. Other ECG criteria for LVH including Sokolow-Lyon, Romhilt-Estes, Framingham, Cornell, and strain alone, achieved a lower sensitivity and prevalence. Over the subsequent follow-up, 244 patients experienced a first major cardiovascular event. Event rate (x 100 person-years) was 2.01 in those without and 4.44 in those with LVH by the C/S index (P <.001). After adjustment for age, sex, smoking, and other counfounders, the C/S index identified subjects at increased risk of events (relative risk 1.76; 95% confidence interval 1.32-2.33). The C/S index achieved the highest population-attributable risk (16.1%) for cardiovascular events. CONCLUSIONS: A simple ECG index that can be quickly measured from nondigital machines and without algorithms identifies LVH in a consistent proportion (16.3%) of hypertensive subjects. The LVH defined by such technique allows identification of individuals at high risk for cardiovascular events.