Right ventricular dysfunction in congenitally corrected transposition of the great arteries and risk of ventricular tachyarrhythmia and sudden death.

BACKGROUND: It is unknown whether systemic right ventricular (SRV) dysfunction confers increased risk for sudden death in congenitally corrected transposition of the great arteries (ccTGA). We sought to define risk of ventricular arrhythmias and sudden death attributable to systemic right ventricular dysfunction in ccTGA.

METHODS: The study cohort is comprised of adult patients with a diagnosis of ccTGA. Clinical information and clinical outcomes including ICD therapy, incidence of VT/VF, and cause of death were reviewed.

RESULTS: 129 patients with ccTGA were followed for 7.2 ± 3.4 years. Mean SRV ejection fraction (SRVEF) was 39% (n = 56 with an EF <35%). Significant documented arrhythmia (sustained VT requiring defibrillation or cardiac arrest due to VT/VF) occurred in 13/56 patients (23%) with SRV EF <35% compared with 2/73 (3%) with SRV EF >35% (p < 0.001). There was no significant difference in age at death, death from documented arrhythmia, or death from all cause between patients with SRV EF <35% and >35%. However, risk of sudden death was higher in patients with SRV EF <35% (16% vs 1%, p = 0.002). The combined clinical endpoint of ICD therapy, clinically significant VT/VF, and sudden death was significantly higher in patients with SRV EF <35% than in patients with SRV EF >35%, independent of the presence of LV EF <35% (p < 0.001).

CONCLUSIONS: Dysfunction of the systemic RV in ccTGA increases the risk of sudden death and clinically significant ventricular tachyarrhythmias. Further study is needed to determine if ventricular tachyarrhythmias comprise the primary cause of sudden death in these patients and if ICDs offer any significant mortality benefit.