Myocardial Performance Index Derived from Preejection Period: A Novel and Feasible Parameter in Evaluation of Cardiac Performance in Patients with Permanent Atrial Fibrillation

Abstract

Using tissue Doppler echocardiography, we can measure preejection period (PEPa), defined as the interval measured from the onset of QRS to the onset of the systolic mitral annular velocity pattern, isovolumic relaxation time (IVRTa), defined as the interval measured from the end of systolic mitral annular velocity pattern to the onset of diastolic mitral annular velocity pattern, and ejection time (ETa), defined as the interval measured from the onset to the end of systolic mitral annular velocity pattern on the same cardiac cycle. The aim of this study is to test the applicability of PEPa-derived myocardial performance index (MPI), defined as the ratio of PEPa + IVRTa to ETa, as an indicator of combined left ventricular systolic and diastolic function in patients with permanent atrial fibrillation. Echocardiographic examination was performed in 54 consecutive patients with permanent atrial fibrillation. Clinical and echocardiographic parameters were compared and analyzed. After a multivariate analysis, the average RR interval on the tissue Doppler image (β=-0.328, P = 0.002), left ventricular ejection fraction (β=-0.260, P = 0.024), and early diastolic mitral annular velocity (β=-0.408, P < 0.001) were the major determinants of PEPa-derived MPI. PEPa-derived MPI had a significant correlation with echocardiographic left ventricular diastolic and systolic function. It may be a novel and feasible indicator in assessment of global left ventricular function in patients with permanent atrial fibrillation.