Long QT and Brugada Syndromes - a coincidence?

Abstract

Introduction: Long QT and Brugada syndromes cause sudden cardiac death (SCD) those with structurally normal hearts. Although implantable cardioverter defibrillators (ICD) prevent SCD, management of those with recurrent ICD shocks remains difficult due to genotypic and phenotypic variations of both conditions. In this report we present the management of a patient with Brugada syndrome and presented with recurrent ICD shocks. Method: N/A. Result: A 34 year-old man presented to the casualty with syncope. Electrocardiogram (ECG) showed cove-type ST elevation at V1 and V2 (Figure 1A). ICD was implanted in accordance with guideline recommendation. Two weeks later, he was readmitted for recurrent ICD shocks and an episode of Torsade de Pointes was documented (Figure 1B). He was discharged after stabilisation with quinidine. Nevertheless, he was admitted again 2 months later for multiple ICD shocks. ECG showed markedly prolonged QTc. Previous ECGs were reviewed and he was confirmed to have prolonged QTc since presentation. Genetic testing found R1192Q and E1783K mutations at the SCN5A gene which are known to cause Long QT and Brugada overlap syndrome. We treated the patient with mexiletine, which selectively blocks INa-L and reduces ICa-L and hence shortens QTc without reducing the peak INa. His QTc was reduced to normal without worsening of ventricular arrhythmias. He remained free from ICD shocks for 2 years. Conclusion: Prolonged QTc is easily overlooked in type I Brugada ECG. It is important to recognise Long QT and Brugada overlap syndrome as quinidine may prolong QTc and worsen ventricular arrhythmias. Mexiletine may be used in patients with long QT and Brugada overlap syndrome.