Case:

Introduction:

The discovery of early repolarization on the electrocardiogram (ECG) of an asymptomatic patient is a relatively common situation which often has been considered as benign.

However recently an identification of a link between the presence of early repolarization in infero-lateral leads and risk of sudden death caused trouble in the emergency and  cardiological communities.

Our case is about a young adult presented with syncope and chest pain alongside with early repolarization pattern (ERP) on his ECG.

Patient Information : On the 5^th of September, 2022, the emergency medical system (EMS) regulations received a call from a peripheral emergency hospital about a 24-year-old male with no medical history brought by his family for a brief loss of consciousness (true syncope) without chest pain.

Clinical Findings: Examination at the emergency department admission reveals a well-oriented conscious patient with bradycardia at 35 c/minute,blood pressure at 110/82 mm Hg without any sign of  peripheral choc and a stable respiratory state with normal pulmonary auscultation,  a respiratory rate at 20 and a blood oxymetry at 97%.

Diagnostic assessment His ECG showed a heart beating in a regular sinus rhythm with bradycardia between 40-50 beats per minute,all the important intervals on this recording are within normal ranges especially PR interval, and an early repolarization pattern .

Therapeutic Intervention: First he received 0.5 mg of atropine to total 4 boluses which mean 2 mg of atropine, than the heart rate increased to 50 c/min and a control of his ECG showed the same pattern with early repolarization (Figure 1).

Follow- up and outcomes: The patient was transported safely with no drugs needed to the cardiology service. The subsequent course marked by recurrence of well-tolerated sinus bradycardia with the same appearance of early repolarization pattern requiring the use of dobutamine and eventually discussing the use of a pacemaker.

Discussion:

The definition of Early Repolarization (ER) has undergone changes since its first description by Wasserburger in 1961. The 2008 definition by Haissaguerre et al. no longer requires ST-segment elevation, but instead requires J-point elevation of at least 0.1 mV in two leads with a slurred or notched appearance. This new definition has led to an increased prevalence of ER in the general population, which now ranges from 6 to 13%. [1] [2]

ER was once considered benign, but recent studies have linked it to a higher risk of death and idiopathic ventricular fibrillation. The discovery of ER's genetic component has expanded its significance, raising questions about inheritance and the need for family screening. Ongoing research into the molecular mechanisms of ER and potential treatments highlights its growing importance. [3]

The link between ER and ventricular fibrillation has been suggested in some reports, with studies suggesting that ER results from an increase in epicardial net outward current leading to J-waves. Adrenergic activation and quinidine suppress ER arrhythmias while vagal influences trigger events during meals and sleep. [4] [5]

The genetic origin of ER is not fully understood, with only a few genes implicated, such as KCNJ8 (ATP sensitive potassium channel) and SCN5A (sodium channel). Certain variants of these genes have been associated with ER and idiopathic VF, but the pathogenic nature of these variants remains uncertain. [6]

There are similarities between ER and Brugada syndrome, but also differences, suggesting they may be related but distinct conditions. ER can appear on an ECG and may indicate an increased risk of arrhythmia. [7]

The link between ER and syncope is unclear, with conflicting evidence and a higher likelihood of vasovagal syncope. A classification system has been proposed based on the location and characteristics of ER and ST segment, with Type 1 (lateral precordial leads) being benign and Type 3 (inferior, lateral, and right precordial leads) being the highest risk, however, this classification has been criticized for a lack of a common pathophysiological basis. [8]

A diagnosis of ER causing VF can only be made after excluding other causes and finding either a high-risk ER pattern or increased parasympathetic tone that leads to high-risk ER characteristics or cardiac arrest during rest or sleep.  [9]Evaluation of sudden cardiac death survivors can lead to a diagnosis in 50% of cases, but the role of extensive investigation for patients with chest pain, syncope, or palpitations should be based on a thorough clinical assessment. ER found in patients with chest pain, palpitations, or syncope is often an incidental finding and current guidelines do not recommend genetic testing, even in the presence of a familial malignant phenotype. [10]

Isoproterenol in acute cases and quinidine in chronic cases were found to be effective in suppressing VF related to ER syndrome in a study of 122 patients with ER in the infero-lateral leads who had more than 3 episodes of idiopathic VF. Other anti-arrhythmic drugs were not found to be effective.

No risk stratification strategy currently exists for asymptomatic patients with ER in the general population or families with ER. Syncope attributed to ER is uncommon and requires aggressive verification of the cause.

As a primary cause of VF, ER Syndrome, is a rare condition. Currently, there are no reliable methods to assess the risk of dangerous ER, despite certain ECG features being associated with higher risk. Patients with asymptomatic ER and no family history of dangerous ER can be reassured that their ECG is normal. All patients with ER should address their modifiable cardiac risk factors.

Conclusion:

Contrary to what has long been considered true, the discovery of early repolarization is not always an innocuous finding on an electrocardiogram. Multiple studies have confirmed that it was associated with an increased risk of cardiovascular mortality.

However, there are still some risks related to this anomaly that are certainly not shared by all patients.

For this reason, we need a better understanding of this Syndrome in order to be able to better identify and treat subjects at risk.

Patient perspective: globally, the patient showed satisfaction with the healthcare during transfer in ambulance.

Declaration of patient consent: the authors certify that they have obtained all appropriate patient consent.

References

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