This case of a 14-year-old girl with congenital heart disease is reported because of the following interesting and unusual features:
1. Dextrocardia and situs inversus with associated congenital cardiac anomaly (atrial septal defect), without cyanosis at the present time.
2. Acute rheumatic fever superimposed upon the above, presenting as an acute surgical abdomen and resulting in a left-sided appendectomy.
3. An electrocardiogram showing an upright P wave in Lead 1 in the presence of a left-sided superior vena cava.
4. The stability of this patient's cardiac status over a period of ten years' observation and in the presence of cardiac