Objective    To study the effect of high pulmonary blood flow and hypoxia in right ventricular remodeling induced by left total pneumonectomy in rats and its mechanism.     Methods    Twenty-four male SD rats were randomly divided into experimental group (left pneumonectomy

n=12) and control group (sham operation

n=12).After 12 weeks of feeding

mean pulmonary arterial pressure (mPAP) of each rat was evaluated using a right cardiac catheterization procedure. Partial artery oxygen pressure was measured. The Ratio of Right ventricular mass/left ventricle plus septum (RV/LV+S) ratio was calculated. Changes in myocardial cells and arterioles were observed.     Results    The mPAP and RV/(LV+S) were obviously higher in experimental group than in control group (P0.01). The partial artery oxygen pressure was lower in experimental group than in control group (P0.01). The diameter of myocardial cells was significantly larger in experimental group than in control group (P0.01). The ratio of myocardial arteriolar medial thickness

external diameter  and medial area to total arteriole area was obviously higher in experimental group than in control group (P0.01). The RV/(LV+S)  was positively correlated with mPAP. mPAP was negatively correlated with partial artery oxygen pressure.     Conclusion    After left total pneumonectomy

high pulmonary blood flow in residual lung and hypoxia can increase pulmonary artery pressure

thus inducing hyperplasia of myocardial arteriole and hypertrophy

i.e

right ventricular remodeling.