CAPTOPRIL REDUCES THE VE VCO(2), RATIO IN MYOCARDIAL-INFARCTION PATIENTS WITH LOW EJECTION FRACTION/

Study objectives: To determine whether captopril (CAP) therapy had an effect on the minute ventilation/carbon dioxide output ((V) over dot E /(V) over dot CO2) ratio at submaximal levels of exercise in asymptoma tic patients with reduced left ventricular function after myocardial i nfarction. Design: Double blinded, randomized, prospective, repeated m easures. Patients and interventions: One hundred thirty-five patients with left ventricular ejection fractions of < 40% were randomly assign ed 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), 1 0 to 14 months (T2), and > 22 months (T3) postmyocardial infarction. M easurements: Oxygen uptake ((V) over dot O-2), (V) over dot CO2, and ( V) over dot E were measured throughout each exercise test. Dependent v ariables were peak (V) over dot ((V)O-2 peak), the ventilatory anaerob ic threshold (VAT), and the (V) over dot E/(V) over dot CO2 ratio meas ured at 30 W and at 75% (V)over dot O-2 peak. Results: VO(2)peak and V AT 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). (V) over dot E/ (V) over dot CO2, was significantly lower for CAP at 30 W (p = 0.05) a nd, although lower at 75% (V)over dot O-2 peak, did not obtain statist ical significance (p = 0.22), The between group differences were large r at T2 and T3 when compared with T1, Conclusions: CAP resulted in a r educed (V) over dot E/(V)over dot CO2 ratio during submaximal exercise . The reduced ventilation may permit patients to pet-form their normal activities of daily living at a lower perception of difficulty, reduc e symptoms, and provide an improved quality of life.