Pathophysiologic determinants of third heart sounds: A prospective clinical and Doppler echocardiographic study

PURPOSE: We sought to determine the importance of a third heart sound (S-3) and its relation to hemodynamic and valvular dysfunction. SUBJECTS AND METHODS: We prospectively enrolled 580 patients who had isolat ed valvular regurgitation (mitral, n = 299; aortic, n = 121) or primary lef t ventricular dysfunction with or without functional mitral regurgitation ( n = 160). We analyzed the associations between the clinical finding of an a udible S3 (as noted in routine clinical practice by internal medicine physi cians) and hemodynamic alterations measured by comprehensive quantitative D oppler echo cardiography. RESULTS: S-3 was more prevalent in patients with primary left ventricular d ysfunction (46%, n = 73) than in organic mitral (16%, n = 47) or aortic (12 %, n = 14) regurgitation (P < 0.001). Patients with an S3 were more likely to have class III-IV symptoms (55% [74 of 137] vs. 18% [80 of 443] of those without an S-3, P < 0.001) and had a higher mean [+/- SD] pulmonary pressu re (55 +/- 15 vs. 41 +/- 11 mm Hg, P < 0.001). An S. was also related to a higher early filling velocity due to a greater filling volume, restrictive filling, or both. An S. was a marker of severe regurgitation (regurgitant f raction greater than or equal to 40%) in patients with primary left ventric ular dysfunction (odds ratio [OR] = 2.4; 95% confidence interval [CI]: 1.1 to 5.5), mitral regurgitation (OR = 17; 95% CI: 5.8 to 52), and aortic regu rgitation (OR = 7.1; 95% Cl: 1.8-28). Am S3 was also associated with restri ctive filling in primary left ventricular dysfunction (OR = 3.0; 95% CI, 1. 6 to 5.9), marked dilatation in mitral regurgitation (OR = 20; 95% CI: 6.8 to 58), and an ejection fraction (< 50%) in aortic regurgitation (OR = 19; 95% CI: 6.0 to 62). CONCLUSION: An audible S., is an important clinical finding, indicating sev ere hemodynamic alterations, and should lead to a comprehensive assessment and consideration of vigorous medical or surgical treatment. (C) 2001 by Ex cerpta Medica, Inc.