PO-713-04 PROGNOSTIC EFFECTS OF ELECTROCARDIOGRAPHIC ST-T WAVE ABNORMALITIES IN THE ALLHAT (ANTIHYPERTENSIVE AND LIPID-LOWERING TREATMENT TO PREVENT HEART ATTACK TRIAL)

Abstract

Major electrocardiographic (ECG) ST-T wave abnormalities are widely seen in clinical practice, but the longitudinal significance in cardiovascular risk assessment within a contemporary hypertension treatment cohort remains unknown. We sought to investigate the relationship between ST-T wave abnormalities and the primary outcome (fatal coronary heart disease or nonfatal myocardial infarction) in the ALLHAT trial. The Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial (ALLHAT) is a randomized double-blinded clinical trial (n=33,357) conducted during 1994- 2002, examining whether treatment with a calcium channel blocker or an angiotensin-converting enzyme inhibitor lowers incidence of CHD or CVD events compared to treatment with a diuretic. 33,357 participants aged 55 years or older with hypertension and at least 1 other CHD risk factor were included and followed up for 4-8 years. Major ST depression or T wave inversion on any ECG in past 2 years were included in the study. The primary outcome was combined fatal CHD or nonfatal myocardial infarction. Hazard ratios (relative risks [RRs]) and 95% confidence intervals (CIs) were obtained from the Cox proportional hazards regression model. Cumulative event rates were calculated using the Kaplan-Meier method. All statistical analyses were performed using STATA 12 (Stata Corp., College Station, TX, USA). Study participants were predominantly middle-aged, male, white, with prevalence of ST-T wave abnormality being 10.35% (N=3,420). Moreover, ST-T changes were associated with a higher risk of fatal CHD or nonfatal MI [hazard ratio 1.17 (95% CI, 1.05-1.29)] in unadjusted analyses. This relationship remained statistically significant after adjustment for prevalent cardiovascular disease (stroke, CABG, ASCVD) [1.15 (95% CI, 1.04- 1.28)], cardiovascular risk factors (age, sex, diabetes, systolic blood pressure, diastolic blood pressure, cholesterol, BMI) [1.21 (95% CI, 1.09-1.34)] as well as randomized treatment groups in ALLHAT [1.21 (95% CI, 1.09-1.34)]. Presence of major ST-T wave abnormality was significantly associated with fatal CHD or nonfatal MI, underscoring the potential prognostic value of these ECG findings in overall cardiovascular risk.