Atrial Flutter-Triggered Ventricular Tachycardia Storm in Gitelman Syndrome: A Case Report.

Gitelman syndrome is an inherited renal tubulopathy characterized by hypokalemia and hypomagnesemia, which can increase susceptibility to cardiac arrhythmias. Although ventricular arrhythmias have been reported, ventricular tachycardia (VT) storm triggered by atrial tachyarrhythmia with recurrent implantable cardioverter-defibrillator (ICD) therapies is uncommon. A 68-year-old woman with Gitelman syndrome, chronic kidney disease stage IIIa, long-QT physiology, and sinus bradycardia status post pacemaker implantation with subsequent dual-chamber ICD placement presented after palpitations followed by over 35-40 ICD therapies. Initial laboratory evaluation showed profound hypokalemia (2.2 mmol/L) and hypomagnesemia (1.6 mg/dL). Electrocardiography demonstrated a narrow-complex atrial tachyarrhythmia most consistent with atrial flutter, while device interrogation revealed a rapid atrial tachyarrhythmia preceding ventricular tachyarrhythmic events. The episode was clinically interpreted as atrial flutter degenerating into sustained VT. After intravenous potassium, magnesium, and metoprolol, she converted to an atrial-paced rhythm but subsequently developed transient rebound hyperkalemia necessitating temporizing therapy. Echocardiography showed preserved left ventricular systolic function. This report highlights a trigger-mediated VT storm in the absence of structural left ventricular dysfunction. Key management strategies included strict electrolyte control, avoidance of proarrhythmic triggers, optimization of ICD programming, and consideration of an electrophysiology study with potential ablation.