Clinical study on the right-sided Austin Flint murmur using intracardiac phonocardiography. 
Right heart catheterization was carried out on 14 patients with pulmonic regurgitation using intracardiac phonocardiography.  All the patients showed pulmonic regurgitant murmur in the right ventricular outflow tract.  In addition, seven out of the 14 patients showed mid-diastolic and presystolic murmurs maximally in the outflow tract of the right ventricle.  Furthermore, inspiration increased the loudness of these diastolic murmurs in four patients.  These findings were compatible with those of right-sided Austin Flint murmur due to functional tricuspid stenosis in pulmonic incompetence.  Ten out of the 14 patients had pulmonary hypertension and all the subjects with a rightsided Austin Flint murmur showed elevated pulmonary arterial pressure.  Thus, pulmonic regurgitation with pulmonary hypertension is thought to be closely related to the right-sided Austin Flint murmur and the turbulence resulting from antegrade flow across a closing tricuspid valve may be responsible for the genesis of the murmur.