Abstract
Pulmonic stenosis (PS) is the second common congenital cardiac disease after aortic stenosis. Echocardiography is a useful tool, and provides the primary means of diagnosis of PS in humans and animals. The pressure gradient (PG) between the right ventricle and pulmonary artery is generally used as an index of severity of PS; a modified Bernoulli equation is adopted for the calculation. But some dogs show no abnormal clinical signs in spite of their PG values being higher than 80 mmHg. Therefore, different parameters which can show a better correlation between PG and the clinical severity of PS are necessary. In the present study, stroke volume decreased in dogs with over 80 mmHg PG values, especially in dogs with over 60% fractional shortening (FS) of the internal diameter of the left ventricle. These seriously ill dogs were found to have a shifted interventricular septum probably due to right ventricular pressure overload. FS, one of the left ventricular systolic function parameters, was also useful in evaluating the pathologic status of PS because FS values were correlative of clinical signs in serious PS cases.
