Histopathologic abnormalities of the sinus node compared with electrocardiographic evidence of sinus node dysfunction after the modified Fontan operation: an autopsy study of 14 cases.

Autopsy specimens from 14 patients who had undergone a modified Fontan operation were evaluated to correlate the extent of histopathologic disruption of the sinus node with electrocardiographic findings of sinus node dysfunction. Patients with sinus node dysfunction (n=7) and those without (n=7) were similar in age, complexity of cardiac malformation, and number of postoperative days at time of death. The degree of fibrosis, local hemorrhage, necrosis, lymphocytic infiltration, and focal calcification of the sinus node and perinodal tissue was also similar in both groups. These findings, which showed a comparable amount of sinus node disruption in patients with normal sinus rhythm and in those with sinus node dysfunction, indicate a lack of correlation between the extent of histopathologic abnormality of the sinus node and electrocardiographic evidence of sinus node dysfunction.