THE HEART AND PERIPHERY IN CARDIAC-FAILURE, RELATION TO EXERCISE TOLERANCE

The aim of the study was to analyze the relationship between tolerance to exercise on the one hand and myocardial dysfunction (central component) and peripheral regional hemodynamic disturbances (peripheral component) on the other hand in 30 patients with congestive heart failure NYHA class I - II (group I) and 13 patients with severe heart failure NYHA class III -IV (group III). All patients underwent invasive cardiopulmonary exercise testing with right heart catheterization and venous occlusive plethysmography. Peak oxygen uptake was significantly higher in group I than in group II (20.3 ml/min/kg vs 12.7 ml/min/kg, respectively, p<0.01). Correlation and regression analyses showed that in mild to moderate heart failure (group I) peak oxygen uptake closely correlated with parameters of central hemodynamics (cardiac index at rest and at peak exercise, right atrial pressure at peak exercise) while its relation to parameters of peripheral hemodynamics was poor. In severe heart failure (group II) peak oxygen uptake was closely related to indices of peripheral but not of central hemodynamics. The results suggest that (1) tolerance to exercise in patients with mild to moderate congestive heart failure is predominantly determined by parameters of central hemodynamics especially by cardiac index; (2) in severe congestive heart failure peripheral factors (venous tone, vascular resistance, arterial blood flow and its reserve) are of greater importance for determination of muscular performance.