Assessing the effect of low dose dobutamine on various diastolic function indexes.

OBJECTIVE: The aim of this study was to evaluate the effect of low dose dobutamine (LDD) on various diastolic function parameters in patients without wall motion abnormality. METHODS: Thirty-one volunteer patients who had no regional wall motion abnormality were included in the study. Echocardiographic measurements were taken both at pre-dobutamine and during LDD infusion. The peak E velocity, A velocity, the E/A ratio, deceleration time (DT), isovolumetric relaxation time (IVRT), myocardial performance index (MPI) and flow propagation velocity (FPV) were assessed as left ventricular diastolic function parameters. Tissue Doppler velocities were also obtained in order to calculate the E/Em and Em/Am ratios. RESULTS: No significant changes were observed in heart rate, E velocity, A velocity, E/A ratio, E/Em ratio, Em/Am ratio, systolic and diastolic blood pressure with LDD. With LDD, DT (239+/-40 ms vs. 201+/-31 ms, p<0.001), IVRT (109+/-12 ms vs. 94+/-11 ms, p<0.001) and MPI (0.57+/-0.15 vs. 0.44+/-0.22, p<0.001) were found to be decreased, while there was an increase in FPV (45+/-8 cm/s vs. 59+/-10 cm/s, p<0.001) and ejection fraction (64+/-6% vs. 66+/-7%, p<0.05). CONCLUSION: Low dose dobutamine (5 mcg/kg of body weight) improves left ventricular relaxation in patients with normal wall motion, while it has no effect on left ventricular filling pressure index.