Exercise-induced upward shift of diastolic left ventricular pressure-volume relation in patients with dilated cardiomyopathy: Effects of β-adrenoceptor blockade

Abstract

Background. The effectiveness of β-blocker therapy for dilated cardiomyopathy (DCM) may be attributed to the inhibition of detrimental effects on the failing heart of sympathetic stimulation during exertion. However, the harmful effects of activity as well as the protective effects of β-blockers have not been demonstrated. Diastolic ventricular function is known to be sensitive to transient myocardial metabolic insult. In this study, we investigated the effect of modest exercise with or without β-blockade on the diastolic left ventricular pressure-volume (P-V) relation in patients with DCM. Methods and Results. The diastolic left ventricular P-V relation was obtained by high-fidelity pressure measurements and digital subtraction left ventriculography at rest and immediately after modest supine bicycle exercise in 12 patients with DCM. The effects of intravenous administration of 0.1 mg kg propranolol on resting and exercise P-V relations were studied. The end-diastolic and lowest left ventricular pressures were significantly elevated by exercise (20±9 to 32±13 mm Hg, P