Beware of early cardiac repolarization

This is an automatically translated article.

The article was professionally consulted with Master, Doctor Nguyen Minh Son - Interventional Cardiologist - Department of Medical Examination & Internal Medicine - Vinmec Nha Trang International General Hospital.
The heart muscle is responsible for circulating blood throughout the body and uses electrical signals from within the heart to manage the heartbeat. When the heart's electrical system is not working as it should, premature repolarization (ERP) can develop and cause premature repolarization syndrome.

1. What is early repolarization syndrome?

Early repolarization syndrome (ERS) is a J-score elevation on the electrocardiogram, previously thought to be a benign entity, but recent studies have demonstrated that it may be associated with a significant risk of cardiac arrhythmias , life-threatening and sudden cardiac death . Early repolarization features associated with sudden cardiac death include J-score amplitude, horizontal or descending ST segment, and inferior or lateral leads.
Prevalence of ERS varies from 3 to 24%, depending on age, sex, and J point elevation (0.05 mV vs 0.1 mV) as the main determinant. Patients with early repolarization syndrome are sporadic and they are at high risk for recurrent cardiac events. Implantation of a defibrillator and isoproterenol are suggested therapies for this patient population. On the other hand, asymptomatic patients with early repolarization syndrome are common and have a better prognosis. Risk stratification in asymptomatic patients with early repolarization syndrome remains a gray area. This review provides an outline of early repolarization syndrome and the risk of life-threatening arrhythmias.

2. What is benign early repolarization? How to monitor for benign early repolarization?

Benign early repolarization (BER) is a typically benign ECG pattern that produces widespread ST-segment elevation, commonly seen in young, healthy patients < 50 years of age. Also known as "takeoff altitude" or "J-point elevation," it can resemble pericarditis or acute myocardial infarction.
Widespread ST elevation in BER may mimic pericarditis or acute myocardial infarction. Up to 10-15% of ED patients presenting with chest pain will have a BER on their ECG, making this a common diagnostic challenge for clinicians. BER is less common in patients over 50 years of age and is particularly rare in those over 70 years of age, where ST elevation is more likely to represent myocardial ischemia.
The physiological basis of BER is not well understood. It is often thought to be a normal variant that is not indicative of underlying heart disease, but there has recently been an association between the global BER pattern and future risk of idiopathic ventricular fibrillation (VF).

3. Is early repolarization syndrome dangerous?

The majority of sudden cardiac death (SCD) cases are related to arrhythmias. The most common electrophysiological mechanism leading to SCD is ventricular arrhythmias. Approximately 10% of SCD cases are associated with known primary electrophysiological disorders (eg, Brugada syndrome) or unknown (eg, idiopathic ventricular fibrillation).
Early repolarization (ER) also known as “J wave” or “J point elevation” is an ECG abnormality consistent with the elevation of the junction between the end of the QRS complex and the beginning of the ST segment in 2 contiguous leads.
Early repolarization syndrome was agreed to be “normal”, a “variant normal” or “benign early repolarization” in 2000.

4. Symptoms of Early Repolarization

ERP patients usually do not have any noticeable physical symptoms. ERP patients also often have a lower baseline heart rate.
ERP can affect anyone. However, it is often diagnosed in young adults, men, and athletes. Until recently, because this condition was commonly associated with healthy young people and athletes, ERP was considered a benign condition. Sometimes, it is even considered a sign of good health. However, recent studies have linked ERP to the development of life-threatening arrhythmias in some cases.

5. Differential diagnosis

Early repolarization syndrome requires a differential diagnosis, including Brugada syndrome, long and short QT syndrome as well as other conditions causing ST-segment elevation (acute ST-segment elevation MI, acute pericarditis and idiopathic ventricular fibrillation). Brugada syndrome (BS), perhaps the closest clinical entity to ERS, is a primary repolarization disorder characterized by prominent J waves causing incomplete right bundle branch block and ST segment elevation in right precordial leads (V1-V3) or significant risk of sudden cardiac death in individuals without obvious structural heart disease.
BS is more common in men. BS symptoms include syncope with or without any warning signs, seizures and nocturnal shortness of breath, electrocardiogram remains the cornerstone of the physician's diagnosis. In fact, sodium channel blockers in most ER patients attenuated J scores, whereas J scores were enhanced by sodium channel blockers in the right precordial leads in patients with Brugada ECGs.
In acute pericarditis, there is an elevated J-score resulting in ST-segment elevation, as seen in the ER. Symptomatic presentation was distinctly different in the two conditions. Unlike the ER, most patients with acute pericarditis have diffuse ST elevation in most or all of the limb and precordial leads. In addition, patients with acute pericarditis often have PR segment changes, which are not present in the ER.
While patients with acute myocardial injury from myocardial infarction have ST-elevation (STEMI), may initially have a high J-score with concave ST-segment elevation, the ST-segment elevation often becoming prominent. more and more convex (rounded up) as the infarct persists. However, the main distinguishing factor between ER and acute myocardial injury is the presence of clinical symptoms such as chest pain or dyspnea. ER and terminal QRS notation should be considered in arrhythmic risk stratification in patients with coronary artery disease and after coronary artery bypass grafting.

6. Early Repolarization Treatments

If the patient is considered not at risk of developing a life-threatening arrhythmia, they may not need treatment. If the patient is considered to be at increased risk for arrhythmias, additional treatments may be used, including defibrillator use, medication, or surgery.
A defibrillator implanted in the chest can help manage the abnormal electrical impulses that cause ERP. Defibrillators use two approaches to prevent fast, irregular heartbeats. This device can stimulate the heart to beat faster than the abnormal rate known as tachycardia, or it can deliver one or more electrical impulses directly to the heart to stop the rhythm.
Medications like Quinidine also work to help the heart fight off abnormal activities. In some cases, a procedure called catheter ablation uses heat to remove the heart's abnormal electrical pathways.
In summary, asymptomatic patients with early repolarization syndrome are quite common and have a better prognosis. Risk stratification in asymptomatic patients with early repolarization syndrome remains a gray area.

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