Abstract 20896: Anticoagulation does not Prevent Atrial Thrombosis in Fontan Patients with Transvenous Atrial Leads

Introduction: Chronotropic incompetency associated with atrial arrhythmias in patients with atriopulmonary Fontan repairs poses technical challenges for atrial pacing. Transvenous atrial pacing is an alternative to the extensive surgery needed for epicardial lead placement in single ventricle patients. Methods: We reviewed prior pacing strategies in 120 consecutive patients undergoing Fontan conversion (FC) with arrhythmia surgery and pacemaker implantation at Children9s Memorial Hospital between 1994 −2008. All pts had functionally single ventricle, with prior Fontan type surgeries. Prior to FC, 32 pts had previous pacemaker implantation, 10 with transvenous or transmural atrial leads; 22 pts with epicardial atrial leads. Charts were reviewed for vascular complications and clinical evidence of atrial thrombus by echocardiogram, and compared with intraoperative findings at FC. Results: Ten pts had prior transvenous (n=9) or transmural (n=1) atrial leads, and adequate anticoagulation was documented in 7/10 pts. Prior ablation procedures were performed before lead placement in 7/10 pts. All pts had preoperative transesophageal echocardiogram; atrial thrombus was detected on one pt who had experienced a prior cerebrovascular accident, resulting in hemiparesis. At the time of FC surgery, massive intra-atrial thrombi were identified in 2 pts; both pts were receiving warfarin for anticoagulation, with documented therapeutic INR. Laminar adherent atrial thrombus was massive in the pt with prior stroke, measuring 9 x 3.9 cm, 1.2 cm in thickness on the atrial lead, with additional intra-cavitary thrombus measuring 5.5 x 4.1 cm, 1 cm in thickness. The second pt had 1.5 x 1.5 cm thrombus on the pacing lead tip. Atrial thrombus was identified in 2/110 pts without intra-atrial leads. P Conclusions: Use of transvenous leads should be avoided in atriopulmonary Fontan repairs, due to risk of developing massive thrombi despite chronic warfarin anticoagulation.