Beneficial effect of salbutamol on cardiac function in severe congestive cardiomyopathy. Effect on systolic and diastolic function of the left ventricle

Abstract

The effects of Salbutamol (a'selective' beta2 agonist) were studied in 12 patients with congestive cardiomyopathy in a dose of 0.5 μg/min/kg. In Study A (n = 6), pressures and cardiac index (CI) were measured at rest and during supine exercise. Study B (n = 6) was specifically designed to observe the effects of Salbutamol on the indices of left ventricular performance and diastolic pressure-volume relationships. The results of Study A revealed Salbutamol infusion significantly (P<0.001) increases CI from 1.8-3.9 l/min/m2 in the resting state; the exercise CI improved from 3 to 4.5 l/min/m2 (P<0.005); there was a marked decrease in left ventricular end-diastolic pressure at rest from 27-13 mm Hg (P<0.001) and during exercise from 39-20 mm Hg (P<0.001). There was no significant change in heart rate and blood pressure. In Study B, there was a significant reduction in left ventricular end-diastolic volume index from 210-183 ml/m2 (P<0.05) and left ventricular end-systolic volume index from 159-102 ml/m2 (P<0.001) with a significant increase in ejection fraction from 28% to 46% (P<0.01). Indices of myocardial performance showed significant improvement in LVdp/dt max (P<0.02), Vpm (P<0.001), Vmax (P<0.01), Vce (P<0.001), V5 (P<0.02), and V40 (P<0.05). Salbutamol infusion significantly decreased end-diastolic circumferential wall stress (P<0.001), total passive diastolic stiffness (P<0.02), elastic stiffness (P<0.001), and increased total left ventricular diastolic compliance (P<0.01). This study indicates that Salbutamol produces significant improvement in overall cardiac function and in both systolic and diastolic function of the left ventricle.