Reproducibility of Transmitral Pulsed Doppler Parameters of Left Ventricular Filling During Dobutamine Stress Test

Abstract

The aim of this study was to investigate the reproducibility of transmitral Doppler parameters of left ventricular filling in subjects undergoing dobutamine stress and to estimate threshold values, which can be used as a reference to detect significant changes in Doppler measurements from baseline to peak dobutamine in an individual patient. The study groups included 11 male volunteers and 26 patients with coronary artery disease. Intra-and interobserver tests were performed on 14 randomly selected tracings. The random variation of measurements (beat-to-beat variations plus random observer error) was estimated at baseline and peak dobutamine both in normals and patients. The parameters studied were: peak early (E) and atrial (A) filling velocities and their ratio (ElA), early filling acceleration (E-AC) and deceleration (E-DC) rates, and diastolic time-velocity integral (TVI). Intra-and interobserver mean differences were generally small (lt; 5%) with the largest found in the interobserver differences in E-AC (12%) and TVI (7%). The random variation of measurements at baseline were similar in normals and patients with the smallest (lt; 5%) variation in E and the largest in E-AC (12%) and El A (8%). There was a significant (P lt; 0.01) increase in the coefficient of variation from baseline to peak dobutamine for E (4.5% vs 7.6%), E-AC (11% vs 14.8%), and E-DC (6.5% vs 9.3%) in the patient group. The threshold values were calculated based on the random variation in a single patient and with the assumption that 3, 5, or 8 beats were analyzed at both instances. Conclusions: When Doppler evaluation of left ventricular filling is used during dobutamine stress, the following points should be considered: (1) peak E has the smallest variability among Doppler indices that assess early filling phase; (2) the variability of Doppler measurements of early filling increases with stress intervention in patients with CAD; (3) increasing the number of beats averaged from 3–8 reduces the threshold needed to decide significant differences in Doppler measurements between baseline and peak dobutamine by more than the half.