Mitral valve closure in atrial flutter.

12 patients who had atrial flutter without clinical, echocardiographic or angiographic evidence of aortic insufficiency were studied with simultaneous echo- and phonocardiograms. In patients with high-grade atrioventricular (AV) block, the mitral valve opened and closed with each flutter wave. Of seven patients, two had persistent and five had intermittent early mitral valve closure before QRS inscription. In five patients (three with 2:1 AV block) the mitral valve closed on time. In one patient with a mitral valve prosthesis, echocardiography and cinefluorography demonstrated closure during mid-diastole, with reopening in late diastole after a flutter wave. Final valve closure occurred before the onset of the QRS, and each closure was associated with a click. Simultaneous phonocardiographic analysis in these patients demonstrated that the first heart sound intensity was inversely related to the degree of mitral valve preclosure. This relationship was independent of the length of the RR interval. Thus, atrial flutter independent of any other cause of abnormal hemodynamics may produce early mitral valve closure. The echocardiographic finding of premature mitral arrhythmias, may not have the same diagnostic or prognostic significance previously described in patients with sinus rhythm and normal AV conduction.