Pathology of the sinus node in d-transposition following the Mustard operation.

In a pathological study of 32 necropsy specimens from patients with d-transposition who had undergone the Mustard operation, lesions were commonly present in the sinus nodal artery, the sinus node, and the paranodal tissues. These had resulted from surgical injury during placement of the atrial baffle and/or closure of the atriotomy incision. Our findings confirm the pathological findings of others. The pathological observations correlate well with reported electrophysiological studies that show frequent occurrence of postoperative supraventricular arrhythmias due to sinus nodal dysfunction. Twenty-six of the patients died in the early postoperative period, and the sinus nodal artery had been compressed by sutures in 46 percent of these cases. The sinus node either showed acute necrosis or compression by sutures in 77 percent of cases, and the paranodal areas were involved by acute hemorrhage and/or necrosis in 100 percent of cases. Six patients died in the late postoperative period. The sinus nodal artery was replaced by fibrous tissue in three and was compressed or thrombosed in two additional instances. The sinus node was extensively fibrosed in each of the six cases. In every instance, the paranodal areas were involved by fibrosis and disruption by sutures.