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Alternation in mitral valve and septal movements in a patient with pulsus alternans.

In a patient with recent aortic valve replacement, echocardiography, phonocardiography, and external pulse recordings were employed to evaluate a prolonged period of pulsus alternans. Alternation in left ventricular end-diastolic and end-systolic diameters, systolic diameter shortening, diastolic ventricular filling, systolic ejection time and diastolic period (A2Q) were seen. In addition, two features were noted which have not been previously reported: (1) Alternation in the timing of mitral valve motion, such that prior to the weak beats, closure of the mitral valve did not occur until 40-70 msec. after the onset of the Q-wave on the ECG. Before the strong beats, however, mitral closure coincided approximately with the Q-wave. (2) Alternation of the movement of the interventricular septum with abnormal or paradoxical movement during weak beats and normal movement during the strong beats. The first observation lends credence to the theory that stretch-tension relationships are important in the maintenance of pulsus alternans in some patients. The paradoxical septal motion during the weak beats may be due either to a discordant right and left ventricular alternans or alternate contractile defection of the septum.