Twenty patients with peripartum cardiomyopathy were followed up for a period ranging from 6-14 months (mean 6 +/- 2 months). At initial evaluation, 16 patients were in New York Heart Association Class IV and the remainder in Class III. During follow up, 12 patients improved to Class I, 7 patients either failed to improve or deteriorated and one patient died. Certain variables at initial evaluation were related to prognosis. The patients who deteriorated, as compared to those who improved, were significantly older (30 +/- 6.8 vs 24 +/- 3 years, P less than 0.01), of higher parity (3 +/- 1 pregnancies vs 1.5 +/- 5 pregnancies, P less than 0.001) and had later onset of symptoms after delivery (7.6 +/- 4 weeks vs 3 +/- 1.3 weeks, P less than 0.001). They also had higher echocardiographic left ventricular end diastolic dimensions (7.0 +/- 8.4 cm vs 3.0 +/- 0.8 cm, P less than 0.001) and higher mean pulmonary arterial (38 +/- 4 mmHg vs 28 +/- 6 mmHg, P less than 0.001) and pulmonary arterial wedge pressures (24 +/- 2 mmHg vs 20 +/- 2 mmHg, P less than 0.001) at cardiac catheterization. Conduction defects were present on the surface electrocardiogram in all the patients who deteriorated, as compared to 4 patients who improved. In conclusion, certain variables at initial evaluation can help in identifying high risk subsets with peripartum cardiomyopathy.