Abstract
OBJECTIVE: Increased plasma concentrations of cyclic guanosine monophosphate (cGMP) have been reported in patients with manifest heart failure. At rest, however, cGMP concentrations in patients with asymptomatic left ventricular dysfunction or heart failure in New York Heart Association (NYHA) functional class I do not differ significantly from those of healthy subjects. The purpose of this study was to investigate whether graded exercise on an ergometer improves the sensitivity of cGMP in diagnosing asymptomatic left ventricular dysfunction. PATIENTS: Plasma cGMP concentrations were compared in 17 healthy controls and 98 patients with asymptomatic left ventricular dysfunction or congestive heart failure of different stages (asymptomatic left ventricular dysfunction or NYHA functional class I, 56 patients; NYHA class II, 31 patients; NYHA class III, 11 patients). RESULTS: Before exercise plasma cGMP concentrations in patients with clinical heart failure (NYHA functional classes II and III) were significantly higher than those in healthy controls. In patients with asymptomatic left ventricular dysfunction or heart failure of functional class I plasma cGMP concentrations were not significantly different from those in healthy subjects. Thirty minutes after exercise, however, cGMP concentrations in patients with asymptomatic left ventricular dysfunction or class I heart failure were significantly higher than those in healthy controls. CONCLUSION: Measurement of plasma cGMP concentrations 30 minutes after ergometric exercise testing allows better discrimination between healthy subjects and patients with symptomless left ventricular dysfunction or mild heart failure (NYHA class I) than measurement of such concentrations before exercise.