Dynamics of regression of right ventricular hypertrophy in rats with hypoxic pulmonary hypertension.

Normobaric hypoxia caused a significant increase in right/left ventricular weight ratio in rats, a reliable indicator of hypertrophy of the right ventricle, already after 1 week of intermittent hypoxic confinement 7 days after termination of a 4-week hypoxic exposure the right/left ventricular weight ratio was significantly lower compared to the values immediately after hypoxic treatment. 8 weeks of sojourning in a normoxic environment were not sufficient to normalize the right ventricular systolic pressure and right/left ventricular weight ratio. It is concluded that changes in the right ventricular mass in rat is a fast reaction to the changes in pressure load.