Background: Early repolarisation syndrome (ERS) is a rare but important cause of sudden cardiac death in otherwise healthy individuals. It is characterised by early repolarisation changes on the electrocardiogram (ECG) and the occurrence of polymorphic ventricular tachycardia or ventricular fibrillation in the absence of other identifiable causes.
Case presentation: A man in his thirties was admitted to hospital following an out-of-hospital cardiac arrest. Coronary angiography and echocardiography revealed no causative abnormalities. Continuous 12-lead ECG monitoring during hospitalisation showed widespread and dynamic J-waves, short-coupled premature ventricular complexes (PVCs) and progressive J-wave augmentation leading up to an in-hospital cardiac arrest. Notably, J-wave augmentation was observed after post-extrasystolic pauses in the period preceding the in-hospital cardiac arrest. Ventricular fibrillation occurred during the phase of maximal J-wave augmentation and was triggered by an 'R-on-T' PVC. Extensive evaluation failed to identify any alternative explanation for the cardiac arrest, and ERS was the final diagnosis. The patient in this case sustained severe anoxic brain injury, and ultimately the decision was made to withdraw life support.
Conclusion: ERS should be considered as a potential cause of cardiac arrest in patients who display early repolarisation changes on the ECG when no other aetiology is found. The diagnosis is further supported by the presence of dynamic J-waves, along with progressive and post-extrasystolic J-wave augmentation observed prior to cardiac arrest.