This study was designed to assess the role of echocardiography in the evaluation and management of patients with the congestive heart failure syndrome. Fifty consecutive patients with congestive heart failure referred for echocardiography were evaluated. Thirty patients (60 percent) had ejection fractions under 50 percent (mean +/- SD 30 +/- 9 percent), left ventricular dilatation (6.5 +/- 0.7 cm), and normal wall thicknesses (1.0 +/- 0.2 cm). The echocardiographic findings were predictable on clinical grounds in 18 of the 30 patients (60 percent) and worse than clinically expected in 12 patients (40 percent). Management changes after echocardiography were indicated in 11 of 30 patients (37 percent). The remaining 20 of the 50-patient cohort (40 percent) had ejection fractions above 50 percent (mean 70 +/- 9 percent, p less than 0.01), and, as a group, were characterized by normal left ventricular size (5.1 +/- 0.8 cm, p less than 0.01) and borderline wall thicknesses (1.1 +/- 0.2 cm, p less than 0.01). The largest subgroup of these 20 patients had hypertensive heart disease (seven patients, 35 percent) associated with the congestive heart failure syndrome presumably related to left ventricular diastolic (compliance) dysfunction. The normal ejection fraction was unexpected clinically in 18 of these 20 patients (90 percent). Recommended management after echocardiography changed in all 18 patients. Since standard clinical findings (history, physical examination, and chest roentgenography) failed to separate patients with normal and abnormal ejection fractions, or those in need of changes in management, echocardiography was a useful and, at times, essential part of the evaluation of these patients with the congestive heart failure syndrome.