Myocardial catecholamine metabolism in patients with chronic aortic regurgitation

In 17 patients suffering from severe chronic aortic regurgitation (AR) (New York Heart Association functional class III), right atrial biopsies were taken during aortic valve replacement. In these samples, we determined the myocardial content of norepinephrine (NE), normetanephrine (NM), epinephrine (E) and dopamine (DA). Two to 4 days before valve replacement, plasma catecholamines were measured at rest and during isometric exercise. Fifteen patients with secundum atrial septal defect (ASD) served as controls. In patients with chronic AR who had no clinical signs of cardiac failure, the myocardial content of NE (p less than 0.025), NM (p less than 0.05) and E (p less than 0.05) was significantly reduced compared with that in patients with ASD. The right atrial content of DA was not different in the two groups. All patients had normal levels of plasma catecholamines at rest. During isometric exercise, however, the increase in plasma NE was significantly higher in patients with AR than in the control group (p less than 0.005). We conclude that patients with chronic AR who have an exaggerated increase in sympathetic activity during isometric exercise probably have a decrease in myocardial NE tissue content as well. Therefore, clinical demonstration of a hyperadrenergic response during isometric exercise indicates alteration in myocardial metabolism in patients with severe chronic AR.