Altered trans-mitral flow velocity pattern after exercise predicts development of new-onset atrial fibrillation in elderly patients with impaired left ventricular relaxation at rest: Prognostic value of diastolic stress echocardiography

Abstract

This study attempted to determine whether exercise induced left ventricular (LV) diastolic dysfunction estimated by altered trans-mitral flow (TMF) velocity pattern after exercise is associated with increased risk of cardiac events including new-onset atrial fibrillation (AF) in elderly patients with impaired LV relaxation at rest. Diastolic stress echocardiography has been applied to evaluate LV diastolic function during and post-exercise. Prognostic importance of exercise-induced diastolic dysfunction remains uncertain. We studied 126 patients (70±5 years; 70 males) who underwent treadmill stress echocardiography. Doppler measurements were done before exercise and immediately after the post-stress image acquisition, and the ratio between early (E) and atrial (A) TMF velocities was measured. Patients with impaired LV relaxation (E/A<1.0) at rest were studied. Altered TMF velocity pattern was present when patients with E/A<1.0 at rest developed E/A≥1.0 after exercise. Primary endpoints for follow-up were combination of major cardiac events and new-onset AF. There were 42 patients with altered TMF velocity pattern after exercise. During the 5-year follow-up period, there were 30 cardiac events including 13 new-onset AF. Kaplan-Meier survival plot demonstrated that altered TMF velocity pattern after exercise is associated with increased risk of cardiac events (p<0.0001) including development of new-onset AF (p=0.0003). Cox hazard ratio analysis demonstrated that altered TMF velocity pattern after exercise was the best predictor of cardiac events (hazard ratio 3.939; 95%confidence interval 1.662-9.337; p=0.0018). Altered TMF velocity pattern after exercise provides significant prognostic information for predicting cardiac events including new-onset AF in elderly patients with impaired left ventricular relaxation at rest.