Differences in ventricular tachycardia inducibility in patients with Tetralogy of Fallot depending on the clinical indication for the electrophysiologic study

Introduction The arrhythmic risk stratification of patients with repaired Tetralogy of Fallot (TOF) is still controversial. The performance of an electrophysiologic (EP) study before pulmonary valve replacement (PVR), regardless of patient's risk factors, is an extended practice in some centers that is not recommended in current guidelines. The aim of our study was to explore the differences in ventricular tachycardia (VT) inducibility in patients with TOF during programmed ventricular stimulation (PVS) depending on the clinical indication. Methods All patients with repaired TOF who underwent an EP study with PVS between January 2001 and October 2020 were included. EP studies performed in the context of ventricular or supraventricular tachycardia ablations that had been previously diagnosed were excluded. We defined two clinical scenarios for performing the EP study: pre-PVR (performed previous to pulmonary valve replacement) or diagnostic EP study (performed due to high risk symptoms which included palpitations, syncope or presyncope). Baseline clinical information, electrocardiogram, echocardiogram and cardiac MRI parameters were retrospective recorded. Results A total of 139 EP studies with PVS were included; 87 in the pre-PVR group and 52 in the diagnostic EP study group. There was a greater incidence of palpitations, syncope and presyncope in the “Diagnostic EP study” group. Moreover, there were statistical significant differences in right ventricle dimensions and function between groups. The repair surgical approach was similar in both groups. It was detected a statistical significant difference in VT induction between the pre-PVR group and the diagnostic indicated group (16,1% vs 34,6%, p=0,012). Conclusions Differences in VT induction are observed during PVS performing in TOF patients depending on the clinical indication. Symptomatology is an important parameter that must be taken into account in order to decide whether to perform an EP study in this population. Funding Acknowledgement Type of funding sources: None.