RESUMEN
BACKGROUND: Expert physicians disagree on the usefulness of the fourth heart sound (S4) as an indicator of left ventricular (LV) diastolic dysfunction. METHODS: We correlated prevalence of the S4 with level of severity of LV diastolic dysfunction. From 551 consecutive echocardiography and Doppler studies, 106 patients in sinus rhythm but without cardiac conduction abnormalities, prosthetic or abnormal valves, or high blood flow states were auscultated by 3 investigators blinded to the participants' diastolic function as determined by 3 other cardiologists using mitral inflow, tissue, and pulmonary vein Doppler interrogation. RESULTS: Diastolic function was normal in 46 participants, 45 had mild, 10 had moderate, and 5 had severe diastolic dysfunction. S4 was audible in 35% with normal function, 42% with mild, 70% with moderate, and none with severe dysfunction (P = 0.052). Sensitivity was 43%, specificity 65%, and accuracy of 53% for discriminating normal from abnormal function. S4 is neither sensitive nor specific, is common but not normal in the elderly, may be absent with severe diastolic dysfunction, and therefore is not a useful indicator of LV diastolic dysfunction. CONCLUSIONS: The S4 is not an accurate indicator of diastolic dysfunction, as it is present in many persons with normal LV function and is absent in those with severe LV dysfunction.