Modifications to the cavopulmonary anastomosis do not eliminate early sinus node dysfunction

Objective: To determine whether operations that theoretically jeopardize th e sinus node (hemi-Fontan and/or lateral tunnel Fontan procedures) are asso ciated with a greater risk of sinus node dysfunction than those that theore tically spare the sinus node (bidirectional Glenn and/or extracardiac condu it). Methods: Between January 1, 1996, and December 31, 1999, a prospective coho rt study was conducted evaluating the incidence of sinus node dysfunction i n patients undergoing a bidirectional Glenn or hemi-Fontan procedure and th ose in whom the Fontan repair was completed with either an extracardiac con duit or a lateral tunnel. Sinus node dysfunction was defined (1) as a heart rate more than 2 SD below age-adjusted norms or (2) as a predominant junct ional rhythm and/or a sinus pause of more than 3 seconds as determined by t he resting electrocardiogram and/or ambulatory monitoring at hospital disch arge. Results: Fifty-one patients had a bidirectional Glenn shunt (mean age 7.8 /- 5.1 months) and 79 a hemi-Fontan procedure (mean age 6.9 +/- 2.8 months) . The incidence of sinus node dysfunction on postoperative day 1 was signif icantly higher after the hemi-Fontan (36%) than after the bidirectional Gle nn shunt (9.8%); however, by hospital discharge this difference was no long er apparent (hemi-Fontan [8%]; bidirectional Glenn [6%]; P = not significan t). No difference in early sinus node dysfunction was discernible after the extracardiac conduit (4/30 [13%]) compared with the lateral tunnel Fontan procedure (6/46 [13%]) (P = not significant). No diagnostic or perioperativ e variables were predictive of sinus node dysfunction. Conclusions: Avoidance of surgery near the sinus node has no discernible ef fect on the development of early sinus node dysfunction. Thus, concerns abo ut early sinus node dysfunction should not override patient anatomy or surg eon preference as determinants of which cavopulmonary anastomosis to perfor m.