RESUMO
Systemic and peripheral hemodynamic response to isometric exercise by handgrip test at 30% maximal voluntary contraction (MVC) for 3 minutes was assessed in 16 patients with congestive heart failure (CHF) after short-term treatment with either captopril or placebo given according to a double-blind, randomized, cross-over sequence. During placebo, isometric exercise increased blood pressure (BP) and total peripheral vascular resistance (TPVR) and decreased cardiac index (CI). Captopril reduced the pressor response to exercise (mean +/- SD) (% systolic: from 14.7 +/- 6 to 11.7 +/- 3; p less than .05/% diastolic: from 12.4 +/- 4 to 8 +/- 3; p less than .005) and increased CI (from 2.3 +/- .6 to 2.6 +/- .9 liters/min/m2; p less than .01) whereas TPVR remained virtually unchanged (from 1479 +/- 597 to 1594 +/- 692 U; NS). The changes in mean BP after exercise were inversely related to the early increase in forearm blood flow (FBF) in exercising forearm during both placebo (r = .67) and captopril (r = .71). The extent of reduction in mean BP response after captopril was inversely related to the extra increase in exercising FBF determined by the drug when compared to placebo (r = .73). We conclude that captopril is able to improve the hemodynamic response to static exercise in patients with CHF, probably by increasing the blood supply to exercising muscles during contraction, thus blunting the extent of reflex pressor response.