Long-term follow-up in the unoperated univentricular heart.

Type A univentricular heart is a severe congenital cardiac defect; 50% of patients are dead 14 years after diagnosis, a death rate of 4.8% per year. Type C univentricular heart is even more lethal; 50% of patients are dead 4 years after diagnosis. Pulmonary stenosis did not protect either group of patients in terms of overall survival. Of the patients in class I or II at initial diagnosis, 34% of patients with type A and 12% of those with type C were in class III or IV or had died at follow-up. The most common causes of death were dysrhythmia, congestive heart failure and sudden and unexplained death.