Task: Question Answering
Input (English): Context: Currently there is no reliable medical treatment for aortic regurgitation (AR).', 'Thirty-nine Sprague-Dawley rats underwent creation of AR or sham operation. Treated rats were assigned to early or late institution of sildenafil therapy (100\xa0mg/kg/day) for a total of 10\xa0weeks. Treatment-effects were measured by serial echocardiography, invasive hemodynamic measurements, and tissue analysis.', 'Rats assigned to early treatment developed less remodeling than untreated rats. Thus, left ventricular (LV) dilation was blunted by sildenafil with end-systolic diameter being significantly smaller (6.6\xa0±\xa00.4 vs. 7.7\xa0±\xa00.4\xa0mm, respectively, p\xa0<\xa00.05). Also, LV wall thickness was significantly decreased in treated rats compared to controls (2.23\xa0±\xa00.08 vs. 2.16\xa0±\xa00.05\xa0mm, p\xa0<\xa00.01). Fractional shortening was improved by treatment (p\xa0<\xa00.05). Myocardial fibrosis was borderline decreased by treatment (p\xa0=\xa00.09). Akt was increased in treated compared to controls (p\xa0<\xa00.05).\Question: Does sildenafil treatment attenuate ventricular remodeling in an experimental model of aortic regurgitation?
Output (English): Sildenafil slightly inhibits LV remodeling and improves fractional shortening in rats with AR when treatment is initiated early.