Usefulness and limitations of precordial phonocardiography and external pulse recordings.

Phonocardiography provides one of a growing list of valuable intermediary studies between physical examination and cardiac catheterization. It not only provides a medium for instruction in physical examination, but also allows one to make certain diagnoses and assess severity of numerous cardiovascular lesions. It is especially valuable in the evaluation of all valvular stenoses, especially aortic stenosis. One can also use phonocardiography for screening and diagnosis of idiopathic hypertrophic subaortic stenosis. It is a helpful adjunct in the study of several congenital abnormalities as well as in the assessment of myocardial function in cardiomyopathies and ischemic heart disease, and may often be decisive in confirming the diagnosis of pericardial constriction.