The Opening Snap of Mitral Stenosis

Sixteen years after Laennec (1819) described the murmur of mitral stenosis, Bouillaud (1835) described a reduplication of the second sound in mitral stenosis. The familiar cadence in mitral stenosis, which results from the presence of this added sound, was likened by Durozier (1862) to the syllables ffou-ta-ta-rou. In 1872 Guttman suggested that this sound might be due not to asynchronism of pulmonary and aortic valve closure, as had been held by Durozier, but to vibration at the stenosed mitral valve itself. Sansom (1881) held the same views as Guttman. It was not until 1888 that Rouches introduced the term commonly used today " claquement d'ouverture de la mitrale " or opening snap of the mitral valve, to describe this sound, stating that Potain had used this term in his teaching. He suggested that the sound was produced by sudden stretching of the stenosed mitral valve by blood passing from the left auricle to the left ventricle. Rouches' views on the pathogenesis of the opening snap were not universally accepted and Gallavardin (1905) and Margolies and Wolferth (1932) made a detailed clinical and phonocardiographic study of this sound and concluded that Rouches' hypothesis as to its mode of production was the most likely.