Reliability of echocardiographic assessment of left ventricular structure and function: the PRESERVE study. Prospective Randomized Study Evaluating Regression of Ventricular Enlargement (see comments)

摘要

OBJECTIVES: The study was done to evaluate reliability of echocardiographic left ventricular (LV) mass. BACKGROUND: Echocardiographic estimation of LV mass is affected by several sources of variability. METHODS: We assessed intrapatient reliability of LV mass measurements in 183 hypertensive patients (68% men, 65 +/- 9 years) enrolled in the Prospective Randomized Enalapril Study Evaluating Regression of Ventricular Enlargement (PRESERVE) trial after a screening echocardiogram (ECHO) showed LV hypertrophy. A second ECHO was repeated at randomization (45 +/- 25 days later). Two-dimensional (2D)-guided M-mode or 2D linear measurements of LV cavity and wall dimensions were verified by one experienced reader. RESULTS: Mean LV mass was similar at first and second ECHO (243 +/- 53 vs. 241 +/- 54 g) and showed high reliability as estimated by intraclass correlation coefficient (RHO) = 0.93. Within-patient 5th, 10th, 90th and 95th percentiles of between-study difference in LV mass were -32 g, -28 g, +25 g and +35 g. Mean LV mass fell less from the first to the second ECHO than expected from a formula to predict regression to the mean (2 +/- 19 vs. 17 +/- 12 g, p < 0.001). Reliability was also high for LV internal diameter (RHO = 0.87), septal (RHO = 0.85) and posterior wall thickness (RHO = 0.83). Substantial or moderate reliability was observed for measures of LV systolic function and diastolic filling (RHO from 0.71 to 0.57). CONCLUSIONS: Left ventricular mass had high reliability and little regression to the mean; between-study LV mass change of +/-35 g or +/-17 g had > or = 95% or > or = 80% likelihood of being true change.