{Reference Type}: Case Reports
{Title}: Case report: Mexiletine suppresses ventricular arrhythmias in Andersen-Tawil syndrome.
{Author}: Yang J;Li K;Lv T;Xie Y;Liu F;Zhang P;Yang J;Li K;Lv T;Xie Y;Liu F;Zhang P;
{Journal}: Front Cardiovasc Med
{Volume}: 9
{Issue}: 0
{Year}: 2022
{Factor}: 5.846
{DOI}: 10.3389/fcvm.2022.992185
{Abstract}: It is arduous to determine clinical solutions for Andersen-Tawil syndrome (ATS) in patients intolerant of β-blocker. Here, we present the case of a 7-year-old boy with periodic paralysis and dysmorphic features who experienced syncope four times during exercise. His ECG revealed enlarged U waves and QU-prolongation associated with ATS-specific U wave patterns, frequent PVCs, and non-sustained bidirectional or polymorphic ventricular tachycardia. The genetic test showed a de novo missense R218W mutation of KCNJ2. With the diagnosis of ATS and intolerance of β-blocker, the patient was prescribed oral medications of mexiletine 450 mg/day without severe adverse effects. The repeat ECG showed decreased PVC burden from 38 to 3% and absence of ventricular tachycardia. He remained symptom-free during over 2 years of outpatient follow-up. This case demonstrates a new anti-arrhythmic therapy with mexiletine for prevention of life-threatening cardiac events in patients with ATS who are intolerant of β-blocker treatment.