Electromechanical Activation Time in the Prediction of Discharge Outcomes in Patients Hospitalized with Acute Heart Failure Syndrome

Abstract

Left ventricular systolic time intervals, including pre-ejection period (PEP), ejection time (ET), and their ratio (PEP/ET), is determined by systolic and diastolic function and ventriculo-arterial coupling. We investigated the usefulness of the electromechanical activation time [(EMAT) PEP minus isovolumic contraction time] in the prediction of cardiac mortality or re-hospitalization for heart failure in patients with the acute heart failure syndrome (AHFS). A total of 45 patients (71.9±16.1 years old) hospitalized for AHFS were enrolled. Systolic time intervals and EMAT normalized by cardiac cycle length (%) were measured separately by separate automated acoustic devices. All parameters were assessed within 24 hours of admission, before discharge, and 2 weeks after discharge. During a mean follow-up of 242±156 days, 20 patients (44%) incurred adverse cardiovascular events including 18 re-hospitalizations for heart failure and 2 cardiovascular deaths. Using uni-variate Cox regression analysis, at admission %EMAT and %PEP, pre-discharge %EMAT, and post-discharge %EMAT significantly predicted post-discharge cardiovascular events with hazard ratios and 95% confidence intervals of 1.75 (1.13-2.70), 1.67 (1.02-2.70), 1.87 (1.10-3.17) and 2.50 (1.58-3.97) per 1-SD increment, respectively. The predictions remained significant after adjustment for age, sex, left ventricular ejection fraction, E/E´ by Doppler echocardiography, and serum N-terminal pro-brain natriuretic peptide. EMAT measured during the hospitalization course is useful in the prediction of cardiovascular outcomes in patients with AHFS independent of left ventricular ejection fraction, E/E´, and serum N-terminal pro-brain natriuretic peptide.