Beneficial effect of continuous normobaric hypoxia on ventricular dilatation in rats with post-infarction heart failure.

Adaptation to continuous normobaric hypoxia (CNH) protects the heart against ischemia/reperfusion injury but much less is known about its potential therapeutic effects. The aim of this study was to find out whether post-infarction exposure to CNH can attenuate the progression of heart failure. Ten-week-old male rats underwent myocardial infarction (MI) or sham operation. MI was induced by 60-min coronary artery occlusion. Seven days post-MI, the rats were randomly assigned to two groups: i) sedentary controls kept at room air and ii) rats exposed to CNH (12 % O(2), 3 weeks). Echocardiographic examination of the left ventricle (LV) was performed 3 days before surgery and 7, 14 and 28 days post-MI. MI resulted in a gradual increase in LV end-diastolic diameter (LVD(d)) compared to sham-operated animals. Fractional shortening (FS) decreased from 42.8 % before MI to 15.1 % on day 28 post-MI. CNH significantly attenuated ventricular dilatation without affecting scar area and FS. Our data suggest that prolonged exposure to CNH has certain potential to attenuate the progression of unfavorable changes in ventricular geometry induced by MI in rats.