Relationship between Mitral Annular Plane Systolic Excursion and Left Ventricular Ejection Fraction by Modified Simpson\'s Method using Point of Care Cardiac Ultrasound: An Observational Analytical Study

INTRODUCTION: The standard accepted method for assessment of left ventricular ejection fraction (LVEF) is modified Simpson's method but it takes time and may not be feasible in emergent conditions. Mitral annular plane systolic excursion (MAPSE) occurs due to contraction of longitudinal fibers and represents myocardial contractility. It is measured on M-mode of ultrasound. It is technically easier and quicker to obtain and may be assessed even with poor cardiac window. OBJECTIVES: The primary objective of this study was to find the relationship between MAPSE and LVEF by modified Simpson's method using point of care cardiac ultrasound. Secondary Objectives were to record the time taken to obtain results by MAPSE and modified Simpson's method, to derive an equation to calculate EF from MAPSE, to compare EF from our equation, equation by Matos et al(2) and modified Simpson's method, validation of derived equation, determination of bias and precision and to find the cutoff value of MAPSE for prediction of a normal or low EF. MATERIALS AND METHODS: A prospective observational study was conducted in two parts. In the first part, 75 patients were recruited for determining the relationship between MAPSE and LVEF by modified Simpson's method. It was validated in the second part in 75 patients by comparing its result with obtained from modified Simpson's method and a previously derived equation. Time taken for the procedure was noted; bias and precision were calculated. RESULTS: MAPSE showed a strong correlation with LVEF calculated by modified Simpson's method. The linear equation obtained was LVEF= 3.27 × (MAPSE in mm) + 17.92 (ρ = 0.761, R2=0.520). Time taken for calculation of MAPSE was quicker (51.47 ± 11.18 s) as compared to that by modified Simpson's method (192.27 ± 31.93 s; p < 0.001). The equation was found to be 89.33% accurate. A MAPSE of 10.325 mm, predicts a normal EF (EF>50%) with a 90.7% sensitivity and 90.6% specificity. CONCLUSION: MAPSE correlates well with the EF measured by modified Simpson's method. It is faster and provides a good estimation as to whether the contractility is preserved or decreased.