Clin Res Cardiol (2021). 10.1007/s00392-021-01933-9

An unusual case of electrical storm in long QT syndrome – sometimes ventricular fibrillation has more than one cause!
D. Lawin1, M. Poudel1, T. Lawrenz1, N. B. Danielsmeier1, A. Tego1, C. Stellbrink1
1Klinik für Kardiologie und intern. Intensivmedizin, Klinikum Bielefeld Mitte, Bielefeld;

Background: Long QT syndrome (LQTS) is a genetically determined disease of cardiac repolarization potentially causing syncope and sudden cardiac death (SCD). LQTS patients at high risk for SCD may require treatment with an implantable cardioverter-defibrillator (ICD). Several triggers can induce ventricular fibrillation (VF) in LQTS patients. Acquired heart disease in addition to LQTS should not be overlooked as highlighted by the case presented. 

Methods and Results: We report on a 47-year-old female patient (pt) with aborted SCD caused by ventricular fibrillation at the age of 23. Genetic testing revealed LQTS and she underwent dual-chamber ICD implantation at that time. After 24 years of event-free survival the pt was referred to our emergency department after experiencing an ICD shock during sleep. Upon arrival in the hospital the pt developed electrical storm with recurrent VF and received overall 6 ICD shocks (Figure 1). Intravenous magnesium was administered which successfully suppressed VF. The pt reported only some paresthesia in both arms and the chest after the ICD discharges but no typical angina pectoris. The initial ECG showed atrial triggered ventricular (VAT) pacing. Despite QRS complex alterations due to pacing distinct inferior ST segment elevations could be discerned (Figure 2). Coronary angiography was immediately performed and revealed subtotal occlusion of the right coronary artery which was treated by drug-eluting stent (DES) implantation. After revascularization ventricular pacing disappeared and atrioventricular conduction immediately resumed. The following non-paced ECG showed a substantially prolonged QT interval (Figure 3). Laboratory assessment confirmed myocardial infarction with elevated cardiac enzymes. Smoking was the only known cardiovascular risk factor. Echocardiography 2 days later revealed normal ejection fraction without wall motion abnormalities. The ICD’s lower frequency limit was set to 80 beats per minute. No more ventricular arrhythmias occurred during the hospitalization. The pt was put on dual antiplatelet therapy, statins and betablockers and discharged in good condition.

Conclusion: This case emphasizes, that diagnostic work-up in patients with confirmed LQTS presenting with electrical storm should not exclude the chance of additional acquired heart disease such as acute coronary syndrome as a potential trigger for electrical storm. Even in a paced ECG signs of ischemia can be discerned which should lead to immediate revascularization if necessary.