Ventricular Arrhythmia in the Fontan Circulation: Prevalence, Risk Factors and Clinical Implications

Objective: Sudden cardiac death (SCD) and malignant ventricular arrhythmia (VA) are increasingly recognized as important issues for people living with a Fontan circulation, but data are lacking. We sought to characterize the cohort who had sudden cardiac death, most likely related to VA and/or documented VA in the Australia and New Zealand Fontan Registry including risk factors and clinical outcomes. Methods: A retrospective cohort study was performed. Inclusion criteria were documented non-sustained ventricular tachycardia, sustained ventricular tachycardia, ventricular fibrillation, resuscitated cardiac arrest or SCD > 30 days post-Fontan completion. Results: Of 1611 patients, 20 (1.2%) had VA; 14 (1.0%) had VA without SCD and 6 (<1%) had SCD (6% of all deaths recorded in Registry; 5 of those had documented VA at the time of arrest and 1 was presumed to be VA -asso-ciated). The median age at first VA was 20.5 (14-32) years, 10 (50%) were females, and the median age at Fontan operation was 8 (4-17) years. On univariable analysis, hypoplastic left heart syndrome (p = 0.03) and older age Fontan operation (p < 0.001) were associated with VA. Earlier Fontan era (p < 0.003), atriopulmonary Fontan (p < 0.001), pre-Fontan atrioventricular valve repair (p = 0.013) pre-or post-Fontan atrial arrhythmia (p = 0.010) were associated with SCD. Patients with VA had a 3 times higher risk of death or heart transplant (HR 3.27(1.19, 8.98), p = 0.02). Conclusions: A proportion of people living with a Fontan circulation have malignant VA. Routine VA screening in this cohort is essential. More data are needed to aid risk stratification.