The Ratio of Early Mitral Inflow Velocity to Global Diastolic Strain Rate as a Useful Predictor of Cardiac Outcomes in Patients with Atrial Fibrillation

Abstract

Although the ratio of early mitral inflow velocity (E) to global diastolic strain rate (E'sr) has been correlated with left ventricular filling pressure, its relationship with cardiac outcomes in patients with atrial fibrillation (AF) has never been evaluated. The aim of this study was to examine the ability of E/E'sr ratio in predicting cardiac outcomes in patients with AF. In 190 patients with persistent AF, comprehensive echocardiography was performed, with assessment of E'sr from three standard apical views using the index beat method. Cardiac events were defined as death and hospitalization for heart failure. There were 50 cardiac events, including 22 deaths and 28 hospitalizations for heart failure, during an average follow-up period of 20 months (interquartile range, 14-32 months). Multivariate analysis showed old age, chronic heart failure, and increased E/E'sr ratio (per 10-cm E/E'sr increase; hazard ratio, 1.258; 95% confidence interval, 1.132-1.398, P < .001) were associated with increased cardiac events. In direct comparison, E/E'sr ratio outperformed the ratio of E to early diastolic mitral annular velocity (E') in predicting adverse cardiac events in both univariate and multivariate models (P ≤ .046). Additionally, the addition of E/E'sr ratio to a clinical model including age, chronic heart failure, diabetes, hypertension, left atrial volume index, left ventricular ejection fraction, and E/E' still provided an extra benefit in the prediction of adverse cardiac events (P = .010). E/E'sr ratio is a useful parameter and is stronger than E/E' ratio in predicting adverse cardiac events, and it may offer additional prognostic benefit over conventional clinical and echocardiographic parameters in patients with AF.