Evaluation of Enalapril+Losartan Treatment with Cardiopulmonary Exercise Test in Patients with Left Ventricular Dysfunction

Abstract

The aim of this study was to evaluate the effects of the combination of enalapril and losartan in patients with left ventricular systolic dysfunction by means of cardiopulmonary exercise test (CPET). Patients with left-ventricular systolic dysfunction and ejection fractions of 40% or less were included to the study. All patients were under the treatment of enalapril 20 mg once daily. The study group consisted of 20 patients (18 men, 2 women; mean age ± standard deviation: 62.4 ±6.5 years) and the comparison group consisted of 10 (8 men, 2 women; mean age 59.3 ±11.9 years). The dose of 50 mg of losartan once daily was given additionally to the study patients. Breath-by-breath CPET was performed before administration of losartan and then 6-8 weeks later in the study group and 2 times with an interval of 6-8 weeks in the control group without any change in the treatment protocol. In the study group the average exercise times were 361 ±192 and 454 ±205 seconds (p=0.001) before and after the study. Peak oxygen consumption (V̇O₂) values were 1,209 ±366 and 1,284 ±398 mL/minute before and after the study (p=0.01). Anaerobic threshold V̇O₂ values were 785 ±187 and 855 ±217 mL/minute before and after the study, respectively (p=0.01). Peak heart rates (HR) were 141 ±28 and 143 ±22/minute (p=0.35); peak V̇O₂/HR values were 9.02 ±3.1 and 9.3 ±3 mL/minute (p=0.4) before and after the study, respectively. On the other hand, in the control group, average exercise times were 556 ±250 and 528 ±251 seconds (p=0.8); peak V̇O₂ values were 1,502 ±537 and 1,450 ±501 mL/minute (p=0.2); and anaerobic threshold V̇O₂ values were 1,005 ±338 and 975 ±319 mL/min (p=0.7), before and after the study respectively. At the highest comparable exercise stage for both tests in the study group the expired volume/oxygen consumption (V̇E/V̇O₂) ratio declined from 35.1 ±6.2 to 32.4 ±5.6 (p=0.007). V V̇E values declined from 37.5 ±10.9 to 33.9 ±10.1 L (p=0.02); heart rate declined from 140 ±27 to 132 ±21/minute (p=0.02). No significant change was observed in the mentioned values for the control group. Addition of losartan to the standard therapy in patients with left ventricular systolic dysfunction improved exercise capacity and caused lower heart rate and ventilation requirements for the same exercise level.