Tetralogy of Fallot with anomalous tricuspid valve simulating pulmonary stenosis with intact septum.

T HE anatomic'-4 and clinical5-7 features and the results of hemodynamic investigations8-10 in the tetralogy of Fallot are now universally known. It has been emphasized that anatomic deviations in the degree of pulmonary stenosis or in the size of the ventricular septal defect may yield different patterns of clinical features and hemodynamics in this anomaly. Recently, we observed 3 cases in which the clinical picture suggested severe pulmonic stenosis with an intact ventricular septum associated with a right-to-left shunt. However, cardiac catheterization showed that the shunt was at the ventricular level. It was demonstrated also that the right ventricular systolic pressure was significantly greater than the systolic pressure in systemic arteries. Therefore, it was assumed clinically that these cases were examples of severe pulmonary stenosis with a small ventricular septal defect. Pathologic examination in one instance (case 1) and the anatomic findings at operation in the other two (cases 2 and 3) demonstrated that the ventricular septal defects were of the usual "large" size seen in the tetralogy of Fallot. In addition to these findings, however, an anomaly of the tricuspid valve was present in all 3 cases. This took the form of a flap of accessory valvular tissue that partially closed the ventricular septal defect during ventricular systole. It is the purpose of this paper to illustrate the clinical and pathologic findings in these 3 cases. To the best of our knowledge, this anatomic entity has not been described previously