Giant fistula between the right coronary artery and the left ventricle: diagnostic significance of right posterior oblique chest radiograph.

Congenital coronary artery fistulas are uncommon. The prevalence of coronary artery fistulas in adults has been estimated as 0.13% [1]. Most of these fistulas communicate with the right atrium or ventricle or with the pulmonary artery; those emptying into the left atrium or ventricle are quite rare [2, 3]. Usually, patients with coronary artery fistula do not have clinical symptoms, and their chest radiographs do not show the corresponding shadow because the fistula is hemodynamically insignificant. When the fistula is large, however, chest radiographs show the secondary hemodynamic changes, such as cardiac enlargement or increased pulmonary vasculature, depending on the emptying site. Moreover, the silhouette of the dilated tortuous vessel itself can be seen on the chest radiograph. We have examined four patients, each of whom had a giant fistula in the right coronary artery emptying into the left ventricle, proved by coronary angiography. In this essay, we illustrate the chest radiographs of these patients and describe the radiologic features that permit a specific diagnosis or suggest a coronary artery fistula.