Read between the lines – Subtle ECG changes to be recognised as a risk factor for sudden cardiac death

摘要

Background: Although the majority of sudden cardiac deaths (SCD) are due to CAD and poor LVEF, there is a considerable fraction of idiopathic ventricular fibrillation (IVF) causing SCD that is secondary to channelopathies and other inherited arrhythmias. Objective: The present report aims to raise awareness about the prevalence of inherited arrhythmogenic disorders, besides the commonly attributed CAD causing SCD. Case report: We report the case of a patient with a history of sudden collapse after routine duty. He had ventricular fibrillation and was successfully defibrillated to normal sinus rhythm. On examination, he was found to have a structurally normal heart, and the ECG showed early repolarisation (ERPS) with a short QT interval. Review of the literature: SCD is defined as IVF in the absence of an identifiable cause. IVF could be the manifestation of concealed forms of arrhythmogenic disorders exacerbated by appropriate triggers. Long QT syndrome presents with structurally normal heart, QT prolongation, syncope, and SCD. Incomplete penetrance gene presents as Brugada syndrome, short QT syndrome, ERPS, sinus node dysfunction, and progressive conduction defects. Subtle ECG changes may be present, which, if identified early, can lead to further focused evaluation, leading to the prevention of a potentially life-threatening arrhythmia. ECG changes that should be looked for include: ERPS changes, especially in the inferior and lateral leads, ‘Rs’ in the inferior leads – >2?mm deep in lead II, small slurred S wave in the inferior leads, incomplete or complete RBBB with J point elevation and coved ST segment in V1 and V2 for Brugada, and long or short QT interval. Conclusion/summary: It is important to recognise channelopathies causing SCD. This is because a majority of these channelopathies are ‘inherited’ and can cause more deaths in the family. Such potential information obtained from ECG features can help categorise patients as ‘suspected high-risk’ and provide appropriate advice.