Sinus node function after a systematically staged Fontan procedure

Background - Sinus node dysfunction has been previously reported to occur in 13% to 16% of patients after the Fontan operation. Although there is concern that an intermediate cavopulmonary connection may increase the risk of sinus node dysfunction, previous studies have not reported on patients routinely staged to a Fontan operation. This study sought to determine the early and late incidences of sinus node dysfunction in patients systematically and uniformly staged to a Fontan operation after a prior hemi- Fontan. Methods and Results - To determine the early incidence of sinus node dysfunction, hospital records and perioperative ECGs were reviewed in all 287 patients having had a staged Fontan operation between January 1990 and December 1995. A cross-sectional analysis was performed on 220 of 239 surviving patients (92%) to determine the late incidence of sinus node dysfunction. Sinus node dysfunction was present in 7% of the patients before and in 15% after the hemi-Fontan. Although most patients (81%) regained normal sinus node function between the 2 stages, 23% had sinus node dysfunction in the early postoperative period after the Fontan. Of the 95 patients followed for >4 years after the Fontan operation, 44% had sinus node dysfunction. However, at a mean follow-up of 3.5±1.7 years, only 16 patients (6.7%) had received a pacemaker and only 10 (4.1%) had documented atrial flutter. Conclusions - Perioperative sinus node dysfunction is common after both the hemi-Fontan and the Fontan procedures. Although many patients regain sinus node function between the 2 stages, late sinus node dysfunction is common and more likely to occur in patients with early sinus node dysfunction and those with longer follow-up.