TANGO2: A Rare but Important Mutation.

We report the case of a 7-year-old boy who presented with post-viral myositis, rhabdomyolysis, and hepatitis, who was later readmitted due to a seizure-like activity and ultimately found to have episodes of recalcitrant polymorphic ventricular tachycardia secondary to simultaneous QT prolongation and severe hypothyroidism. Temporary transvenous atrial pacing was successful at controlling the ventricular arrhythmias in the intensive care unit. With levothyroxine therapy and cessation of QT-prolonging medications, the corrected QT (QTc) normalized. A comprehensive arrhythmia panel identified a pathogenic mutation in KCNQ1, consistent with long QT syndrome (LQTS) type 1. After the patient experienced progressive neurodegeneration and seizures, he was referred to a genetics clinic to rule out genetic epilepsy. On the epilepsy panel of genetic testing, he was found to have two pathogenic variants in TANGO2. TANGO2 deficiency explains the initial presentation of myositis, rhabdomyolysis, hypothyroidism, and life-threatening arrhythmias surrounding a viral illness more so than the initial diagnosis of mere LQTS. However, the TANGO2 gene is not included in most comprehensive arrhythmia and cardiomyopathy panels. TANGO2 deficiency is a rare condition that often presents with arrhythmias but may be unfamiliar to many cardiologists and electrophysiologists. This case describes management strategies and caveats, which could aid in the successful diagnosis and treatment of TANGO2 deficiency at the time of presentation.

Oral Anticoagulation Use in High-Risk Patients Is Improved by Elimination of False-Positive and Inactive Atrial Fibrillation Cases.

BACKGROUND: Multiple registries have reported that >40% of high-risk atrial fibrillation patients are not taking oral anticoagulants. The purpose of our study was to determine the presence or absence of active atrial fibrillation and CHA2DS2-VASc (Congestive heart failure, Hypertension, Age ≥75 y, Diabetes mellitus, prior Stroke [or transient ischemic attack or thromboembolism], Vascular disease, Age 65-74 y, Sex category) risk factors to accurately identify high-risk atrial fibrillation (CHA2DS2-VASc ≥2) patients requiring oral anticoagulants and the magnitude of the anticoagulant treatment gap. METHODS: We retrospectively adjudicated 6514 patients with atrial fibrillation documented by at least one of: billing diagnosis, electronic medical record encounter diagnosis, electronic medical record problem list, or electrocardiogram interpretation. RESULTS: After review, 4555/6514 (69.9%) had active atrial fibrillation, while 1201 had no documented history of atrial fibrillation and 758 had a history of atrial fibrillation that was no longer active. After removing the 1201 patients without a confirmed atrial fibrillation diagnosis, oral anticoagulant use in high-risk patients increased to 71.1% (P < .0001 compared with 62.9% at baseline). Oral anticoagulant use increased to 79.7% when the 758 inactive atrial fibrillation patients were also eliminated from the analysis (P < .0001 compared with baseline). In the active high-risk atrial fibrillation group, there was no significant difference in the use of oral anticoagulants between men (80.7%) and women (78.8%) with a CHA2DS2-VASc ≥2, or in women with a CHA2DS2-VASc ≥3 (79.9%). CONCLUSIONS: Current registries and health system health records with unadjudicated diagnoses over-report the number of high-risk atrial fibrillation patients not taking oral anticoagulants. Expert adjudication identifies a smaller treatment gap than previously described.