Early Repolarisation - What Should the Clinician Do?

Why Is There an Increased Risk for Sudden Cardiac Death in Patients With Early Repolarization Syndrome?

The last two decades have changed the viewpoint on early repolarization syndrome (ERS). The prevalence of the early repolarization pattern is variable and ranges between 3-24% depending upon age, gender, and criteria used for J-point upliftment from baseline (0.05mV vs. 1 mV). While this pattern was previously linked with a benign result, multiple recent investigations have found a link between early repolarization and Sudden Cardiac Death (SCD) by causing life-threatening arrhythmias like Ventricular tachycardia/Ventricular fibrillation, a condition known as early repolarization syndrome. The syndrome falls under a broader bracket of J wave syndromes, which can be caused by early repolarization or depolarization abnormalities. The characteristics of early repolarization that are considered high risk for Sudden Cardiac Death include the amplitude of J-point upliftment from baseline ( > 0.2 mV), Inferior-lateral location of Early Repolarization pattern, and horizontal and downsloping ST-segment. Patients with symptomatic early repolarisation patterns on ECG are more likely to have repeated cardiac episodes. Implantable Cardioverter-Defibrillator (ICD) implantation and isoproterenol are the recommended treatments in symptomatic patients. On the other hand, asymptomatic patients with early repolarization patterns are prevalent and have a better outcome. Risk categorization is still obscure in asymptomatic early repolarization patterns. This traditional review outlines the known knowledge of pathophysiology behind the increased risk of sudden cardiac death, risk stratification of patients with ERS, and the treatment guidelines for patients with ERS. Further prospective studies are recommended to elucidate the exact mechanism for ventricular arrhythmogenesis in ERS patients and to risk stratifying asymptomatic patients with ERS.

The Spectrum of Idiopathic Ventricular Fibrillation and J-Wave Syndromes: Novel Mapping Insights

Idiopathic ventricular fibrillation and J-wave syndromes are causes of sudden cardiac death (SCD) without any identified structural cardiac disease after extensive investigations. Recent data show that high-density electrophysiological mapping may ultimately offer diagnoses of subclinical diseases in most patients including those termed "unexplained" SCD. Three major conditions can underlie the occurrence of SCD: (1) localized depolarization abnormalities (due to microstructural myocardial alteration), (2) Purkinje abnormalities manifesting as triggering ectopy and inducible reentry; or (3) repolarization heterogeneities. Each condition may result from a spectrum of pathophysiologic processes with implications for individual therapy.

Depolarization versus repolarization abnormality underlying inferolateral J-wave syndromes: New concepts in sudden cardiac death with apparently normal hearts

Early repolarization indicates a distinct electrocardiographic phenotype affecting the junction between the QRS complex and the ST segment in inferolateral leads (inferolateral J-wave syndromes). It has been considered a benign electrocardiographic variant for decades, but recent clinical studies have demonstrated its arrhythmogenicity in a small subset, supported by experimental studies showing transmural dispersion of repolarization. Here we review the current knowledge and the issues of risk stratification that limit clinical management. In addition, we report on new mapping data of patients refractory to pharmacologic treatment using high-density electrogram mapping at the time of inscription of J wave. These data demonstrate that distinct substrates, delayed depolarization, and abnormal early repolarization underlie inferolateral J-wave syndromes, with significant implications. Finally, based on these data, we propose a new simplified mechanistic classification of sudden cardiac deaths without apparent structural heart disease.