Emotional stress has been considered responsible for life-threatening ventricular arrhythmias but acute stress-induced heart failure has not been reported in man. Two patients with recent uncomplicated myocardial infarction presenting acute pulmonary edema immediately after psychologic stress testing are the object of this report. Four stressors, mental arithmetic, 30 emotionally involving questions (Sacks' test modified), an image quiz (Raven's matrices) and white noise were administered during hemodynamic monitoring (Swan-Ganz catheter) in a 3-min stress-5-min recovery sequence. Response to the stressors was not unusual; greatest cardiovascular response occurred during mental arithmetic, least during noise and intermediate patterns were induced by the other stressors. Heart rate and systemic blood pressure, markers of autonomic activation, increased moderately. Neither ventricular arrhythmias nor ischemic electrocardiographic changes were observed during or after stress testing. Complete recovery followed each stress-induced cardiovascular response. About 10 min after completing stress testing, acute pulmonary edema occurred in both patients neither of whom had presented other episodes of acute pulmonary edema, suggesting that psychologic stress may induce pump dysfunction in patients with latent heart failure.