Skip to Main Content
Using specially designed catheters and amplifying equipment, studies of intracardiac sounds have been carried out in man at the time of cardiac catheterization. The catheters, either single- or double-lumen, are passed into the lesser circulation under fluoroscopic guidance. The first and second heart sounds are heard in the heart and in the great vessels leading to and from the heart. The first sound is loudest in the ventricle and the second sound is loudest in the pulmonary artery. In some cases a third heart sound has been detected. In all cases with atrial contractions, a fourth sound is detected and is loudest in the atrium. With atrial fibrillation no fourth sound is heard. Even when no murmurs are heard on the chest or in the heart, there is routinely a midsystolic murmur in the pulmonary artery. In the presence of disease, abnormal murmurs are heard inside the heart. In certain types of congenital heart disease the localization of the murmur is of help in the diagnosis. Records are shown to illustrate that this technique is capable of localizing heart sounds and murmurs to an extent not heretofore obtainable.