Surveillance Electrophysiology Studies Reveal High Incidence Of Inducible Ventricular Arrhythmias In Adults With Congenital Heart Disease

Background: Adults with congenital heart disease (ACHD) have a 25–100 times increased risk of sudden cardiac death (SCD), presumably from ventricular arrhythmias (VA). To date, few clinical predictors help identify patients (pts) most at risk, and no clear indication exists for primary prevention with implantable cardioverter defibrillator (ICD) therapy. Therefore, to prospectively identify high risk pts and ultimately guide therapy, we sought to determine the incidence of significant VA in a population of ACHD using surveillance electrophysiologic studies (S-EPS). Methods: S-EPS were prospectively performed on all pts >18 yrs with complex CHD scheduled for transcatheter or surgical intervention. Pts were excluded if they had an indication (non-surveillance) for EPS including prior VA or syncope. Demographic, clinical, diagnostic, and interventional findings were compared in pts with positive (+VA) and negative (-VA) EPS for inducible VA (VT/VF) using T-test, Pearson’s Chi-square, and Fisher’s exact test. Results: From 1/05–12/05, 24 pts, mean age 29.4+/−10.1 yrs (range 19.2– 61.5), underwent S-EPS. VAs were induced in 45.8% (n=11). Diagnoses in +VA include d-transposition of the great arteries (n=4), tetralogy of Fallot (n=4), pulmonary stenosis (n=2), and Ebstein anomaly (n=1). No difference exists in pts with +VA vs -VA with respect to diagnosis, age at primary repair, time since repair, NYHA class, presence of RBBB, QRS and QTc duration, Lown criteria on 24 hour ambulatory monitoring, and CT/MRI LV and RV dimensions and EF. Interventions for +VA included cryoablation, ICD and/or antiarrhythmic therapy, or surgical intervention only. Thus far, 2/5 repeat EPS were positive and resulted in ICD placement. Conclusions: ACHD are at increased risk for malignant VA and SCD. This is the first report of S-EPS for risk stratification in this population. Nearly 50% of S-EPS were positive for inducible VA. In our study, abnormal ECG, Holter monitoring, or cardiac CT/MRI findings did not predict +VA with S-EPS. Long term studies are necessary to define the role of S-EPS in ACHD direct therapies, and determine whether guided intervention leads to a reduction in SCD.