Case report of a patient with congenital long QT syndrome Type 2 presenting with electrical storm: do not judge a book by its cover!

Background: Patients with congenital long QT syndrome (LQTS) are at high risk for sudden cardiac death (SCD). Although several triggers can provoke ventricular fibrillation (VF) in patients suffering from LQTS acquired heart disease in addition to LQTS should not be overlooked.

Case Summary: We present a case of a 47-year-old female patient who was diagnosed with congenital LQTS Type 2 at the age of 23 after surviving SCD. At that time, she underwent implantable cardioverter-defibrillator (ICD) implantation and was free of events for 24 years. Recently, the patient was referred to our institution after suffering from an ICD shock during sleep. Upon arrival she developed electrical storm and received overall six ICD shocks. The initial electrocardiogram (ECG) showed atrially triggered ventricular pacing. However, distinct ST segment elevations in the inferior leads could be observed. Thus, coronary angiography was immediately performed and showed subtotal occlusion of the right coronary artery, which was treated by drug-eluting stent implantation. Atrioventricular conduction immediately resumed after revascularization and the following non-paced ECG revealed a prolonged QT interval. Laboratory measurements confirmed acute myocardial infarction with elevated cardiac enzymes. The patient was put on betablockers, dual antiplatelet therapy, and statins and discharged in good condition.

Discussion: This case report highlights that diagnostic work-up in patients with LQTS presenting with VF should always include the search for additional acquired heart disease such as myocardial infarction, as a potential trigger for electrical storm. Moreover, signs of ischaemia can be discerned even in a paced ECG which should lead to immediate cardiac catheterization.