The effect of the angiotensin converting enzyme inhibitor, enalapril, on exercise tolerance and abnormalities of limb blood flow and respiratory function in patients with severe heart failure.
Ten patients with severe (NYHAIII) heart failure were compared with 10 age-matched healthy subjects in terms of oxygen uptake and minute ventilation at rest and during exercise and calf and forearm blood flow measured by venous occlusion plethysmography at rest and after a standardized exercise test. Patients performed a symptom-limited treadmill exercise test and were then treated with enalapril for 5 weeks; the various measurements were repeated at weekly intervals. Oxygen consumption (VO2) at rest was similar in the patients and controls. During exercise, patients VO2 tended to be lower at each workload, but this was not affected by enalapril treatment. Minute ventilation was higher at rest and at each exercise stage in the patients than in the control subjects, and this was significantly reduced by enalapril treatment. Compared with the controls (2.94 +/- 0.10 and 2.93 +/- 0.20 ml.100 ml-1.min-1) forearm and calf blood flow measured by venous occlusion plethysmography was reduced at rest in the patients (1.34 +/- 0.18 and 1.24 +/- 0.11 ml.100 ml-1.min-1). but was significantly increased by enalapril treatment (1.73 +/- 0.15 and 1.60 +/- 0.16 ml.100 ml-1.min-1). Submaximal leg exercise to a fixed VO2 showed attenuation of the normal vasoconstriction in the forearm and vasodilatation of the calf; enalapril treatment changed these responses significantly towards normal but a marked abnormality of flow pattern persisted.
Division of Cardiovascular Medicine, University Hospital, Queen's Medical Centre, Nottingham, U.K.
A J
AJ
Cowley
J M
JM
Rowley
K
K
Stainer
J R
JR
Hampton
D000368:Aged; D001132:Arm / Q000098:blood supply; D002311:Cardiomyopathy, Dilated / Q000188:drug therapy* / Q000503:physiopathology; D004656:Enalapril / Q000494:pharmacology* / Q000627:therapeutic use; D005080:Exercise Test; D017079:Exercise Tolerance / Q000187:drug effects*; D006801:Humans; D007866:Leg / Q000098:blood supply; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000098:blood supply*; D017202:Myocardial Ischemia / Q000188:drug therapy* / Q000503:physiopathology; D010101:Oxygen Consumption / Q000187:drug effects; D012039:Regional Blood Flow / Q000187:drug effects; D012119:Respiration / Q000187:drug effects*
D004656:Enalapril