Clinical Electrophysiology -> SVT/AVNRT/WPW/AT: -> Epidemiology of Cardiac Arrhythmias/ Epidemiology D-PO01 - Featured Poster Session (ID 11) Poster

D-PO01-033 - An International Cohort Of Andersen Tawil Syndrome: Characterization Of The Cardiac Phenotype, ICD Outcomes, And Antiarrhythmic Therapy (ID 52)


Background: Andersen Tawil Syndrome (ATS) is an autosomal dominant disorder characterized by arrhythmia, periodic paralysis, dysmorphic features, and a neurocognitive phenotype. Arrhythmias in ATS include polymorphic and bidirectional ventricular ectopy.
Objective: A multicenter, international collaborative was used to characterize the cardiac phenotype and outcomes in ATS.
Methods: Databases at 3 large ATS referral centers were queried for patients meeting clinical or genetic criteria for ATS, focusing on cardiac phenotype and therapy. Descriptive statistics were used and data are expressed as mean ± standard deviation.
Results: We identified 101 ATS patients. Mean age was 40 ± 19.5 years. Among 72 patients with ECG data, the QTc was 441 ms ± 52. A U wave was present in 33 (45%), with QUc of 621 ms ± 60, and U wave amplitude of 0.094 mV ± 0.046. Among 61 patients with ambulatory monitoring data available, 56 (92%) had ventricular ectopy (VE), 50 (82%) PVCs, 25 (41%) ventricular bigeminy, 36 (59%) ventricular tachycardia (VT), 20 (33%) bidirectional VT, 14 (23%) polymorphic VT, 4 (7%) ventricular fibrillation (VF), and 3 (5%) had torsades de pointes. There were 16 patients with an ICD, with a follow-up of 11 ± 12 years. ICD indications included VT with syncope or VF (n=3), history of VE or syncope (n=4), VE without syncope (n=6), or combination of prolonged QTc with syncope or family history of sudden cardiac death (SCD, n=3). Eight (50%) patients had device related complications, including 6 (38%) requiring surgical intervention. There were 8 (50%) who had an inappropriate shock. The 5 patients with an appropriate shock had a history of VT with syncope or family history of SCD. Antiarrhythmic therapy was recorded for 28 (28%), with 19 (68%) having received β blockers and 13 (46%) flecainide. Patients on flecainide showed a reduction in VE when pre- and post-treatment data were available.
Conclusion: In a large cohort of ATS patients, the predominant cardiac phenotype was a high burden of VE including bidirectional and polymorphic VT. Life threatening arrhythmias were uncommon and SCD rare. In patients with ICDs, complications including inappropriate shocks were frequent. Longitudinal, collaborative studies are needed to better define appropriate ATS therapy.