Pulmonary pulsus alternans in acute myocardial infarction

Abstract

A total of 100 consecutive patients with acute myocardial infarction were studied with hemodynamic monitoring. Five groups were established: A, all eight patients with pulmonary pulsus alternans; B, the four patients in group A who did not die; C, the four patients in group A who died in the coronary care unit; D, control patients with heart failure, but without pulmonary alternans; and E, patients in group A who underwent hemodynamic studies just before (five patients) the appearance of pulmonary pulsus alternans and six patients studied just after its disappearance. Patients in group A had a smaller cardiac index (2 P < 0.005), stroke index (2 P < 0.05), left ventricular stroke work index (2 P < 0.01) and higher pulmonary resistance levels (2 P < 0.005) than patients in control group D. They also had a smaller cardiac index (2 P < 0.005) and higher pulmonary resistance (2 P < 0.05) levels than patients in group E. Patients in group B had a higher stroke index (2 P < 0.05), left ventricular stroke work index and left ventricular net work index (2 P < 0.01) than patients in group C. Appearance of pulmonary pulsus alternans accompanied a decrease in cardiac index and an increase in pulmonary pressure and resistance levels. Its disappearance sometimes followed a drug-induced decrease in pulmonary pressure and resistance levels, and an increase in cardiac index. On other occasions it occurred after the administration of inotropic agents (digoxin or dopamine), without changes in pulmonary pressure. Pulmonary pulsus alternans in acute myocardial infarction may appear under two conditions: (1) right ventricular strain secondary to left heart failure; and (2) impaired right ventricular contractility. Mortality was greater in group A than in group D (2 P < 0.05). Patients in group C were in worse condition than those in group B. Therefore, the prognosis depends on the degree of heart failure and not on the pulmonary pulsus alternans itself.