在正常儿童及青年 ,第三心音 (Ｓ3)是生理性的 ,但在 40岁以上者则常为病理性。本文前瞻性研究单纯性瓣膜反流或原发性左室功能障碍患者中Ｓ3的病理生理决定因素。方法　研究对象为单纯性二尖瓣反流或主动脉瓣反流 ,或原发性左室功能障碍患者 ,应用多普勒超声心动描记术对反流? In normal children and adolescents, the third heart sound (S3) is physiologically, but it is often pathologic in people over 40 years of age. This prospective study of patients with simple valvular regurgitation or primary left ventricular dysfunction in the pathophysiology of S3 determinants. Methods The subjects were simple mitral regurgitation or aortic regurgitation, or primary left ventricular dysfunction. Doppler echocardiography was used to evaluate the regurgitation.