P2.022: A loop in time – Atypical syncope harkens Aborted VF arrest in Andersen Tawil syndrome

Introduction:

Background: Andersen–Tawil syndrome (ATS) is a rare inherited channelopathy characterized by periodic paralysis, ventricular tachycardia (VT), and craniofacial/limb anomalies. Despite frequent non sustained VT, life-threatening VF is rare.

Case Description: Case:
Patient was a 15-year-old female with frequent PVCs, non-sustained VT and symptoms of orthostatic syncope. At age 21 she underwent ablation attempt for presumed idiopathic PVCs/VT and 3 foci in the LV septum were ablated with acute success. Non sustained VT returned, and her syncope evolved- now without prodrome. She was referred to our clinic.

Discussion: DECISION MAKING:
Physical examination demonstrated micrognathia, hypertelorism and clinodactyly. Genetic testing revealed pathogenic KCNJ2 mutation. Cascade screening demonstrated multiple other affected members in the family. Nadolol and flecainide were implemented. Loop recorder was implanted to correlate her rhythm to her evolving syncope. Within a week, she experienced aborted VF arrest while resting. She underwent transvenous dual chamber ICD implantation and a switch to sotalol and mexiletine therapy. She has had no shocks in 2 years of follow up.

Conclusion: CONCLUSION – ATS should be suspected when encountering frequent polymorphic and non-sustained PVC/VT with dysmorphic features. Syncope though common finding is often unrelated to arrhythmia (orthostatic syncope or periodic paralysis). Rhythm surveillance may help identify those rare patients who will benefit from implantable device therapy.