Cardiovascular reserve in idiopathic dilated cardiomyopathy as determined by exercise response during cardiac catheterization

Abstract Simultaneous right- and left-sided cardiac high-fidelity hemodynamic measurments were obtained at rest and supine exercise during cardiac catheterization in 27 patients (mean age 32 ± 10 years) with idiopathic dilated cardiomyopathy to investigate the hemodynamic exercise response and possible mechanisms for the wide variation in exercise tolerance observed clinically. There were no significant differences in other rest hemodynamic variables between group 1, patients with a normal exercise factor (more than 600, n=10), and group 2, patients with an abnormal exercise factor (less than 600, n=17). A greater increase in stoke volume index (12 ± 6 vs 2 ± 8 ml/beats/m 2 , mean ± standard deviation) and a greater decrease in systemic vascular resistance with exercise occurred in group 1 than in group 2 (−614 ± 304 vs −406 ± 291 dynes cm −5 ). Elevation of right ventricular end-diastolic pressure with exercise was significantly greater in group 2 than in group 1 (7 ± 5 vs 1 ± 4 mm Hg, respectively, p