Exercise Improves Flow-Mediated Vasodilatation of Skeletal Muscle Arteries in Rats With Chronic Heart Failure Role of Nitric Oxide, Prostanoids, and Oxidant Stress

Background—Flow-mediated dilatation (FMD) of the peripheral arteries may be impaired in chronic heart failure (CHF), and this could contribute to the increased peripheral resistance and exercise intolerance that occur with this disease. Physical exercise improves the FMD of large conduit arteries in CHF, but whether a similar impairment also occurs in smaller arteries is unknown. The mechanisms of the changes in FMD after CHF or exercise are also unknown. Methods and Results—FMD was assessed in isolated, perfused, and preconstricted gracilis muscle arteries from sham-operated rats or CHF rats (coronary artery ligation) who were either sedentary or exercised (30-minute swimming period twice a day for 10 weeks, starting 7 days after ligation). In animals with hemodynamic and echographic signs of CHF, FMD was abolished and converted into vasoconstriction (percent change in diameter after 370 μL/min flow: sham, 42±5%; CHF, −4±3%; P<0.05). Exercise partially restored FMD (18±3%; P<0.05 versus CHF). In sham rat...