To determine whether captopril (CAP) therapy had an effect on the minute ventilation/carbon dioxide output (VE/VCO2) ratio at submaximal levels of exercise in asymptomatic patients with reduced left ventricular function after myocardial infarction.Design
Double blinded, randomized, prospective, repeated measures.Patients and interventions
One hundred thirty-five patients with left ventricular ejection fractions of < 40% were randomly assigned to a treatment group (CAP; n = 62) or a placebo group (PLC; n = 73). Subjects had cycle ergometer exercise tests at 2 to 6 months (T1), 10 to 14 months (T2), and > 22 months (T3) postmyocardial infarction.Measurements
Oxygen uptake (VO2), VCO2, and VE were measured throughout each exercise test. Dependent variables were peak VO2 (VO2 peak), the ventilatory anaerobic threshold (VAT), and the VE/VCO2 ratio measured at 30 W and at 75% VO2 peak.Results
VO2 peak and VAT did not differ as a result of treatment (CAP vs PLC; p = 0.92 and 0.80) or over time (T1 vs T2 vs T3; p = 0.51 and 0.07). VE/VCO (2) was significantly lower for CAP at 30 W (p = 0.05) and, although lower at 75% VO2 peak, did not obtain statistical significance (p = 0.22). The between group differences were larger at T2 and T3 when compared with T1.Conclusions
CAP resulted in a reduced VE/VCO2 ratio during submaximal exercise. The reduced ventilation may permit patients to perform their normal activities of daily living at a lower perception of difficulty, reduce symptoms, and provide an improved quality of life.