Arterial wave reflection in heart failure

Arterial wave reflection may adversely influence both left ventricular afterload and ejection performance. Therefore, using multisensor catheter manometers, we derived wave reflection indexes from ascending aortic pressure and velocity recordings in 17 subjects with clinical heart failure secondary to idiopathic dilated cardiomyopathy and 11 control subjects free of detectable cardiovascular disease. Patients were studied at rest as well as during submaximal supine bicycle exercise. Eight of the subjects with cardiomyopathy were also studied during infusion of nitroprusside at rest and on exercise. Reflection indexes decreased on exercise in normal subjects but did not consistently do so in the subjects with heart failure. In both groups the reflected wave on exercise returned earlier during the ejection period. Infusion of nitroprusside at rest in subjects with heart failure had dramatic, and significant, effects on the magnitude and timing of arterial wave reflections. The effect of nitroprusside on reflection magnitude persisted on exercise, although the timing of the reflected wave was disadvantageous. The systemic arterial response to exercise in heart failure is characterized by a smaller change in wave reflection indexes in spite of a comparable decrease in systemic vascular resistance. Nitroprusside diminishes the potentially adverse impact of wave reflections by decreasing the magnitude of the reflected wave and altering its timing. Additional dose titration studies are necessary to fully assess the benefits of pharmacologic vasodilation during exercise.