Coronary blood supply of the inferior wall of the right ventricle in hearts with Ebstein malformation: relevance to vertical plication.

OBJECTIVE

Vertical plication of the atrialized chamber in Ebstein malformation has been subject to debate. A major argument against it is risk of coronary arterial injury; however, the coronary anatomy in the malformation remains incompletely investigated.

METHODS

We examined 17 autopsied hearts with the malformation. Special attention was paid to the coronary blood supply of the right ventricular inferior wall, focusing on the course of the posterior descending branch and its relationship with the interventricular septum.

RESULTS

The right coronary artery was dominant in 11 cases (65%); the remaining 6 had left dominance. In 6 right-dominant hearts, the right coronary artery gave rise to the branch before reaching the crux of the heart. This early takeoff caused the entire branch to be deviated rightward. Another 2 right-dominant hearts showed rightward deviation of the branch course after an initial short segment along the septum. In contrast, in 2 left-dominant hearts, the left circumflex artery ran beyond the crux and then gave rise to the branch, again resulting in rightward deviation of the branch. These deviations allowed the branch to run on the thin walled part of the right ventricular inferior wall where endocardial stitches are placed during typical vertical plication.

CONCLUSION

The posterior descending branch was frequently (10/17, 59%) deviated toward the right side relative to the interventricular septum in hearts with Ebstein malformation. Because of this and the thinness of the atrialized ventricular wall, care should be taken to the branch even with superficial endothelial stitches.