Afterload reduction with vasodilators and diuretics decreases mitral regurgitation during upright exercise in advanced heart failure

Abstract

In advanced heart failure, mitral regurgitation increases the burden of the failing ventricle and decreases effective stroke volume. Although tailored afterload reduction decreases mitral regurgitation at rest, it is not known if this benefit is maintained during upright exercise. Simultaneous radionuclide ventriculography and thermodilution stroke volumes were compared to measure the forward ejection fraction in 10 patients during upright bicycle exercise before and after therapy with vasodilators and diuretics tailored to decrease pulmonary capillary wedge pressure and systemic vascular resistance.Ventricular volumes, total ejection fraction and the forward ejection fraction did not change during exercise at baseline. At rest, tailored therapy decreased average pulmonary capillary wedge pressure from 36 to 19 mm Hg (p < 0.01), systemic vascular resistance from 1,570 to 1,210 dynes·s·cm−5 (p < 0.05), and left ventricular volume index from 251 to 177 ml/m2 (p < 0.01), while increasing the forward ejection fraction from 0.53 to 0.85 (p < 0.01) without change in total ejection fraction (0.18 from 0.17). During steady state exercise at low work load, tailored therapy decreased left ventricular volume index from 279 to 213 (p < 0.05) and increased forward ejection fraction from 0.52 to 0.79 (p < 0.01) without change in total ejection fraction (0.20 from 0.19).The total stroke volume during exercise was not increased after therapy; the increase in forward stroke volume after therapy appeared to result instead from the decrease in mitral regurgitant flow. The benefits of tailored afterload reduction are maintained throughout upright exercise.