Against the Storm: Salvaging Refractory Arrhythmia with Mexiletine

Introduction: Ventricular tachycardia (VT) storm is a condition characterized by recurrent ventricular arrhythmias within a 24-hour period, requiring a device or pharmacologic intervention. Despite its clinical significance, data on VT storm prevalence and treatment outcomes in the Filipino population remain limited. Case Report: We present a 69-year-old male with heart failure from non-ischemic cardiomyopathy and an implantable cardioverter-defibrillator (ICD), who experienced multiple VT episodes unresponsive to amiodarone, lidocaine and mechanical cardioversion. He was initially admitted for catheter ablation but later developed a left ventricular thrombus precluding the procedure. Mexiletine was introduced and successfully suppressed arrhythmia recurrence. Case Discussion: This case emphasized the complexity of managing ES, especially in patients with contraindications to ablation. Mexiletine, a class IB antiarrhythmic agent structurally similar to lidocaine, has shown efficacy in refractory VT, especially when standard therapies are ineffective or are contraindicated. Limited data exists on its safety for such cases, particularly in patients with intracardiac thrombus. Conclusion: Mexiletine may offer a viable treatment option for VT storm in patients ineligible for ablation due to left ventricular thrombus. While it was effective in this case, further studies are needed to validate its safety and long-term outcomes in similar high-risk populations. Keywords: Ventricular Tachycardia, Electrical Storm, Implantable Cardioverter-Defibrillator, Mexiletine, Intracardiac Thrombus, Catheter Ablation Contraindications