Right ventricular systolic pressure gradients in aortic valve disease.

Obstruction to ventricular outflow may be either discrete and fixed, or dynamic and variable. A fixed obstruction is most common at valvar level but occasionally it may be subvalvar or supravalvar. Dynamic or functional obstruction is associated with hypertrophy of ventricular muscle and is invariably subvalvar. This latter type of functional obstruction was first recognized in the right ventricle where subvalvar muscle hypertrophy developed as a result of severe pulmonary valve stenosis. Surgical treatment of the valvar lesion unmasked the subvalvar obstruction (Kirklin et al., 1953; Brock, 1955; Rodbard and Shaffer, 1956). A similar type of muscular obstruction was later recognized in the left ventricle by Brock (1957). Dynamic obstruction to left ventricular outflow due to an unknown disorder of cardiac muscle has been reported by many authors and variously called obstructive cardiomyopathy (Goodwin et al., 1960), muscular subaortic stenosis (Brent et al., 1960), or idiopathic hypertrophic subaortic stenosis (Braunwald et al., 1960). Pressure gradients between the right ventricle and the pulmonary artery have been noted in association with left ventricular obstructive cardiomyopathy (Braunwald et al., 1964; Cohen et al., 1964) and in idiopathic combined ventricular hypertrophy without demonstrable left ventricular outflow obstruction (Taylor, Bernstein, and Jose, 1964; Braunwald et al., 1964). We occasionally found systolic pressure gradients between the right ventricle and pulmonary artery in patients with aortic valve disease, and this observation suggested that it would be worth while to investigate the nature and site of this obstruction. The purpose of this paper is to show that severe left ventricular disease may produce secondary effects