Abstract Body (Do not enter title and authors here): Background: Patients with systemic right ventricle (sRV), including congenitally corrected transposition of great arteries (cc-TGA) and dextro-transposition of great arteries (d-TGA) post-atrial switch procedure are at risk of sudden cardiac death due to ventricular arrhythmias (VA). While programmed ventricular stimulation (PVS) can help with risk stratification in certain patients with congenital heart disease, its role in sRV is unknown.
Objective: To study the diagnostic value of electrophysiology study (EPS) in predicting VAs in patients with sRV.
Methods: EPS was performed in 53 patients with sRV at Mayo Clinic from 1994 to 2021. Patients with a history of sustained VA or cardiac arrest were excluded (n=19). The incidence of sustained VA (sudden cardiac death, sustained ventricular tachycardia [VT] or appropriate implantable cardioverter-defibrillator [ICD] therapy) was evaluated in the remaining 34 patients. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of EPS in predicting VAs is reported.
Results: The mean age at EPS was 36.2±11.6 years, 21 (61.8%) were male, 21 (61.8%) had d-TGA and mean sRV ejection fraction was 31.3±10.8%. Indication for EPS was supraventricular tachycardias (n=15, 44.1%), syncope/palpitations (n=9, 26.5%) and non-sustained VT (n=6, 17.6%). 13/34 (38.2%) patients had inducible sustained VA, (5 [38.5%] with monomorphic VT and 8 [61.5%] with polymorphic VT/VF). Treatments included ICD implantation in all 13 patients and ablation in one patient. During a mean follow-up of 8±5.4 years, one patient with a positive PVS (inducible polymorphic VT) experienced sustained VT secondary to atrial flutter with 1:1 conduction. The sensitivity of PVS was 100%, specificity was 63.6%, PPV 7.7%, and NPV 100%.
Conclusion: In this retrospective cohort of patients with sRV, polymorphic VT was the most commonly observed VA during PVS. The predictive value of a positive PVS was low in this cohort, and larger studies are needed to better define the role of EPS in risk stratification. Patients with negative EPS did not have future VAs recognizing that the overall event rate is low. Further multicenter research with a larger sample is required to develop predictive models to identify those at risk of VAs.