Differential diagnosis of pulmonic stenosis by means of intracardiac phonocardiography.

The purpose of the present paper is to describe the origin of the systolic murmur in pulmonic stenosis and to discuss the diagnostic possibilities of intracardiac phonocardiography. Right heart catheterization was carried out with the aid of a double-lumen A.E.L. phonocatheter on 48 pulmonic stenosis patients with or without associated heart lesions. The diagnosis was confirmed by heart catheterization and angiocardiography in all cases and in 38 of them, by surgical intervention. Simultaneous phonocardiograms were recorded with intracardiac pressure tracings. In valvular pulmonic stenosis, the maximum ejection systolic murmur was localized in the pulmonary artery above the pulmonic valve and well transmitted to both right and left pulmonary arteries, the superior vena cava, and right and left atria. The maximal intensity of the ejection systolic murmur in infundibular stenosis was found in the outflow tract of right ventricle. The contractility of the infundibulum greatly contributes to the formation of the ejection systolic murmur in the outflow tract of right ventricle. In tetralogy of Fallot, the major systolic murmur is caused by the pulmonic stenosis, whereas the high ventricular septal defect is not responsible for it. In pulmonary branch stenosis, the systolic murmur was recorded distally to the site of stenosis. Intracardiac phonocardiography has proved useful for the differential diagnosis of various types of pulmonic stenosis.