Short QT Syndrome Masquerading as Lone Atrial Fibrillation: Hidden in Plain Sight.

BACKGROUND

We present a case of short QT syndrome (SQTS) initially manifesting as atrial fibrillation (AF) and degenerating to polymorphic ventricular tachycardia (PMVT), successfully managed with quinidine.

CASE SUMMARY: A 66-year-old man presented with palpitations and was found to be in AF with a QTc interval of 335 ms. He developed PMVT with hemodynamic collapse, requiring 3 successive defibrillation shocks. Refractory to amiodarone and lidocaine, he met Gollob criteria for SQTS. He was successfully managed with oral quinidine, resulting in QTc normalization to 430 ms. A secondary prevention implantable cardioverter-defibrillator was implanted. Genetic testing was unrevealing. He remained arrhythmia-free at 6 months.

DISCUSSION: With an estimated prevalence of 0.02%, SQTS is frequently underrecognized. This case underscores the specific efficacy of quinidine in normalizing the QT interval and suppressing malignant ventricular arrhythmias in SQTS.

TAKE-HOME MESSAGE: Prompt recognition of a short QTc interval is crucial in patients presenting with PMVT, as diagnosis directs targeted pharmacologic therapy with quinidine.