Role of right ventricular infarction in cardiogenic shock associated with inferior myocardial infarction.

Abstract

To assess the role of right ventricular and left ventricular dysfunction in patients with cardiogenic shock associated with combined right ventricular and inferior myocardial infarction, the clinical records and hemodynamic data of 18 patients with inferior myocardial infarction and cardiogenic shock were reviewed. Of these patients 6 had hemodynamic evidence of right ventricular dysfunction. There was no significant difference in left ventricular stroke work index between patients with (18 .+-. 3 g/m2) and without (14 .+-. 2) associated right ventricular dysfunction. Though pulmonary artery wedge mean pressure was significantly lower in patients with right ventricular dysfunction (10 .+-. 1 mm Hg) than in those without right ventricular dysfunction (18 .+-. 2), this difference is probably the consequence of the right ventricular damage, since all patients with right ventricular dysfunction had a wedge pressure 11 mm Hg or less compared with only 3 of 12 patients without right ventricular impairment. Necropsy observations in 8 patients including 2 with right ventricular dysfunction support this concept. All patients had 40% or more infarction (old plus new) of the left ventricle. The 2 with right ventricular infarction had wedge pressures 10 mmHg or less whereas the other six without right ventricular infarction had wedge pressure 14 mm Hg or more. While all 5 patients with right ventricular dysfunction who were treated by plasma volume expansion had a rise in wedge pressure (16 .+-. 1 after fluid therapy) only 2 survived. Mortality in the group with right ventricular dysfunction (3 of 6) was similar to that in the group without right ventricular dysfunction (7 of 12). In patients with cardiogenic shock associated with combined right ventricular and inferior myocardial infarction, low pulmonary artery wedge pressure is the result primarily of right ventricular dysfunction and does not necessarily imply that left ventricular damage is slight and severe left ventricular damage, often with a relatively low wedge pressure, is more common than was previously reported in these patients.