Transvenous right atrial and left ventricular pacing after the Fontan operation: long-term hemodynamic and electrophysiologic benefit of early atrioventricular resynchronization.

We report a case of long-term, successful, endocardial atrioventricular pacing in a 32-year-old man who had severe heart failure and ascites after having undergone a Fontan procedure for tricuspid atresia 9 years earlier. The patient was referred to our hospital for Fontan revision. However, electroanatomic mapping of the right atrium revealed viable tissue at the interatrial septum above the os of the coronary sinus, and it appeared that the left ventricle could be paced from a coronary sinus branch. Therefore, instead of Fontan revision, an endocardial atrioventricular pacemaker was implanted transvenously. On 5-year follow-up, the patient remained in New York Heart Association functional class I and had not been readmitted to the hospital for congestive heart failure or arrhythmias. His atrial and ventricular leads continued to show excellent pacing and sensing results.