More Experienced Physicians May Be More Accurate At Detecting Third Heart Sound
In a study, based on cardiac examination of actual patients, physicians with more clinical experience were more likely to accurately detect a third heart sound, according to a second article in the March 27 issue of the Archives of Internal Medicine.
The third heart sound can be heard in early diastole (a phase of the heart's pumping cycle), according to background information in the article. This specific heart sound could indicate problems in the function of the heart's left ventricle and may increase risk of adverse effects in patients undergoing noncardiac surgery and also in those with heart failure or acute myocardial infarction (heart attack). "Identification of this valuable physical finding requires relatively little time, and it is accessible to any physician with a stethoscope," the authors write. "However, studies have demonstrated very poor interobserver agreement among physicians and have suggested that trainees may not receive adequate instruction in auscultation," or listening for the sound.
Gregory Marcus, M.D., and colleagues at the University of California, San Francisco, performed a study of 100 patients (65 men and 35 women) undergoing a diagnostic test known as cardiac catheterization. The patients were examined by four physicians-one attending cardiologist, one cardiology fellow, one internal medicine resident and one internal medicine intern. The patients also underwent other tests, including one known as phonocardiographic analysis, which provided a 10-second recording of each patients' heartbeat that was analyzed by computer for a third heart sound.
Phonocardiography detected third heart sounds in 21 (23 percent) of the 90 patients whose readings were valid. The researchers assessed how well the physician examiners did compared with phonocardiography and found that cardiology fellows and attending cardiologists displayed a fair amount of agreement with the computer-analyzed results. Interns and residents, however, did not display any significant agreement with phonocardiography. The more experienced the physician, the higher the association between hearing the third heart sound and other clinical markers of ventricular dysfunction in patients, including the results of tests known as left ventricular ejection fraction and recording of left ventricular end-diastolic pressure. Phonocardiography, however, remained superior to all physicians' examinations.
"The clear improvement in auscultatory accuracy by the fellows compared with the residents and interns may be due in part to the emphasis on the cardiac physical examination and regular bedside teaching by senior cardiologists provided to the cardiology fellows," the authors write. "It is also possible that individuals with greater interest in or skill at clinical auscultation may pursue cardiology specialty training." All physicians can improve their skills through continued interest and mentorship from an experienced practitioner, they conclude. (Arch Intern Med. 2006;166:617-622)