Left ventricular function in patients with acute myocardial infarction, acute pulmonary edema, and mechanical ventilation: relationship to prognosis

Abstract

Objectives: To evaluate the relationship between left ventricular function and prognosis in patients treated with mechanical ventilation for severe, persistent pulmonary edema as a consequence of acute myocardial infarction.

Design: A prospective study.

Setting: A nine-bed coronary care unit in a 900-bed teaching hospital.

Patients: Sixty-nine successive patients.

Interventions: All patients had acute pulmonary edema not responding to classical treatment and were treated with mechanical ventilation.

Measurements and main results: The inhospital mortality rate was 67%. Thirteen of 23 patients surviving hospitalization died during follow-up, a mean of 5.8 +/- 7.7 months after infarction. Six of ten long-term survivors are in functional capacity class 1 or 2 (New York Heart Association) and four survivors are in class 3. Echocardiographic examination indicated that severe left ventricular dysfunction was present in most patients during the time of mechanical ventilation. Repeat echocardiographic examination performed 14.2 +/- 8.1 months after infarction showed a remarkable improvement in left ventricular function among the survivors. Multivariate analysis indicated that the small group of patients with a good long-term prognosis could not be separated prospectively from the larger group dying during or after hospitalization using variables obtained at the time of mechanical ventilation.

Conclusions: The mortality rate is high in this group of patients. Left ventricular function of survivors is severely diminished at the time of infarction but improves markedly during follow-up. The small subgroup of patients with a good long-term prognosis cannot be identified prospectively when evaluated during the acute stage of infarction and the provision of mechanical ventilation.