Ventricular arrhythmia risk stratification in patients with tetralogy of fallot at the time of pulmonary valve replacement

Background - Most patients with repaired tetralogy of Fallot require pulmonary valve replacement (PVR), but the evaluation for and management of ventricular arrhythmia remain unclear. This study is aimed at clarifying the optimal approach to this potentially life-threatening issue at the time of PVR. Methods and Results - A retrospective analysis was performed on 205 patients with repaired tetralogy of Fallot undergoing PVR at our institution between 1988 and 2010. Median age was 32.9 (range, 25.6) years. Previous ventricular tachycardia occurred in 16 patients (8%) and 37 (16%) had left ventricular dysfunction, defined as left ventricular ejection fraction <50%. Surgical right ventricular outflow tract cryoablation was performed in 22 patients (10.7%). The primary outcome was a combined event including ventricular tachycardia, out-of-hospital cardiac arrest, appropriate implantable cardioverter defibrillator therapy, and sudden cardiac death. Freedom from the combined event at 5, 10, and 15 years was 95%, 90%, and 79%, respectively. In the first year after PVR, 2 events occurred. Conversely, in the 22 patients who underwent surgical cryoablation, a single event occurred 7 years after PVR. A history of ventricular tachycardia and left ventricular dysfunction was associated with higher risk for the combined event (hazard ratio, 4.7; P=0.004 and hazard ratio, 0.8; P=0.02, respectively). Conclusions - Patients with repaired tetralogy of Fallot undergoing PVR with history of ventricular tachycardia or left ventricular dysfunction appear to be associated with a higher risk of arrhythmic events after operation. Events in the first year after PVR are rare, and in select high-risk patients, surgical cryoablation does not seem to increase arrhythmic events and may be protective.