Case report: factors involved in the production of the presystolic murmur in a patient with mitral stenosis and atrial trigeminy. Correlation of echocardiographic, phonocardiographic, and hemodynamic data.

The study of a patient with mitral stenosis and periods of atrial trigeminal rhythm afforded an opportunity to test some factors important in the production of the presystolic murmur. The echocardiogram and phonocardiogram were correlated with hemodynamic data obtained both with the patient at rest and with right atrial and ventricular pacing. The results showed that atrial contraction was a major determinant in the production of the presystolic murmur and seemed to exert an even greater influence than did either the end-diastolic pressure gradient across the mitral valve or the duration of the preceding RR interval. Corollaries from this study may have practical application for the clinician in his bedside physical examination. The data suggested that the production of the presystolic murmur in our patient might have been related to geometrical shifts of intracardiac anatomical structures resulting from changes in the left ventricular end-diastolic distending pressure.