RELATION OF FUNCTIONAL IMPROVEMENT IN CONGESTIVE-HEART-FAILURE AFTER QUINAPRIL THERAPY TO PERIPHERAL LIMITATION

Angiotensin-converting enzyme inhibitors have been shown to increase m aximal muscle blood flow in parallel to peak VO2 in patients with cong estive heart failure (CHF). Whether this increase shifts factors limit ing peak aerobic capacity from periphery (skeletal muscle or vessels) to central factors (cardiac or respiratory) is unknown. Comparison of peak oxygen consumption (VO2)) obtained during leg cycling (VO2 leg) w ith peak VO2 obtained during combined leg cycling and arm cranking VO2 arm + leg) allows determination of the relative role of central or pe ripheral factors. We compared VO2 leg with VO2 arm + leg before and af ter 3 months of therapy with quinapril 40 mg in 16 patients with CHF ( age 53 +/- 13 years) due to left ventricular systolic dysfunction (eje ction fraction 0.25 +/- 0.07). Before quinapril, VO2 arm + leg was sig nificantly higher than VO2 leg (19.0 +/- 3.3 vs 16.9 +/- 3.8 ml/kg/min , p < 0.001), whereas after therapy these 2 values were similar (20.3 +/- 4.3 vs 21.0 +/- 4.3 ml/kg/min; p = NS), indicating that patients w ere no longer limited by peripheral factors. Besides, VO2 leg increase after therapy was higher in patients in whom difference between VO2 a rm + leg and VO2, leg was the greatest (i.e., in patients who were ini tially more limited by peripheral factors). Simultaneously, calf peak reactive hyperemia and circumference significantly increased, indicati ng an improvement in vascular dilating capacity and an increase in ske letal muscle mass. No significant modification occurred in the forearm . Thus, patients who improved the most after 3 months of quinapril the rapy were those who were initially limited by peripheral factors. The restricting role of these factors was reduced after quinapril therapy. (C) 1997 by Excerpta Medica, Inc.