Early repolarization
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and keywords: early repolarization pattern; early repol; early repol variant
Overview
Early repolarization is defined as either a notch described as a positive deflection after a positive QRS segment or a J point elevation of more than 0.1 mV described as slurring of the morphology of the terminal QRS complexin at least two consecutive leads.[1] While early repolarization has been long considered as a normal benign ECG variant, some studies suggests an association between early repolarization and increased risk of arrhythmia, particularly ventricular fibrillation[1]. In addition, early repolarization can be confused with ST elevation MI and pericarditis.
Natural History, Complications and Prognosis
- Early repolarization pattern has been considered benign for a long time until some studies suggested an association between early repolarization and increased risk of arrhythmia, particularly ventricular fibrillation.[1] A possible explanation of the increased vulnerability to ventricular fibrillation associated with early repolarization is that early repolarization might be an indicator of transmural repolarization heterogeneity.[2]
- This association has shed light on the importance of evaluating early repolarization patterns and their prognostic implications. Whereas early repolarization is a common finding, idiopathic ventricular fibrillation is a rare entity which incidence ranges from 3:100000 to 10:100000.
- The majority of early repolarization patterns, especially if incidentally found in otherwise asymptomatic people with a negative family history, have no or minimal increased risk of arrhythmia.
- Early repolarization carries a higher risk of arrhythmia in patients with underlying cardiac pathology.
- Early repolarization is rarely associated with a primary arrythmogenic disorder that manifests as idiopathic ventricular fibrillation. Genetic predisposition seems to play a role in this group of people. In addition, early repolarization seems to cause arrhythmia during sleep or at rest in the absence of any physical activity.[1]
- In addition, early repolarization seems to have different patterns which have different clinical significance. Hence, a standardized evaluation of early repolarization is needed.apidly ascending. Early repolarization patterns that demonstrate a rapidly ascending ST segment after the J point are almost always benign.[3]
- A case control study of 120 post MI patients with implantable cardioverter defibrillators (ICDs) demonstrated that early repolarization was more frequently observed among patients with documented episodes of VT/VF (32% vs. 8%, p=0.005). The leads demonstrating early repolarization were more often the inferior leads (23% vs. 8%, p=0.03). A trend was observed for the lateral leads (V4-V6) as well (12% vs. 3%, p=0.11). In contrast, leads I and aVL were not commonly involved (3% vs. 0%). The morphology of the ST segment was critical and a notch in the ST segment was observed more frequently among patients with VT/VF (28% vs. 7%, p=0.008). In contrast, J-point elevation and slurring of the ST segment surprisingly were not associated with ventricular arrhythmias.[4]
Differential Diagnosis
Early repolarization must be differentiated from other causes of ST elevation including ST elevation MI and pericarditis.
- The ST segment elevation of early repolarization is exacerbated by bradycardia, carotid sinus massage and vagal maneuvers This is not true in ST elevation MI or pericarditis.
- Early repolarization is characterized by a notch at the J point which is not a characteristic finding in ST elevation MI or pericarditis. Shown below is an image demonstrating a characteristic notch which is present at the J point in early repolarization.
- The height of the J point can be used to differenciate early depolarization from other conditions. Only lead V6 is used to distinguish between early repolarization and pericarditis. As shown in the image below, if A/B > 25%, pericarditis should be suspected. If A/B < 25%, early repolarization is most probable.
EKG Examples
Shown below is an EKG demonstrating J point elevation, concave shaped up-sloping ST segment, and prominent T waves in the inferior and lateral leads depicting benign early repolarization.
Shown below is an EKG demonstrating notching of the J point in the lateral leads depicting early repolarization.
Shown below are examples of EKG depicting early repolarization and other normal variants of ST elevation.
References
- ↑ 1.0 1.1 1.2 1.3 Obeyesekere, MN.; Klein, GJ.; Nattel, S.; Leong-Sit, P.; Gula, LJ.; Skanes, AC.; Yee, R.; Krahn, AD. (2013). "A clinical approach to early repolarization". Circulation. 127 (15): 1620–9. doi:10.1161/CIRCULATIONAHA.112.143149. PMID 23588960. Unknown parameter
|month=ignored (help) - ↑ Wu, SH.; Lin, XX.; Cheng, YJ.; Qiang, CC.; Zhang, J. (2013). "Early repolarization pattern and risk for arrhythmia death: a meta-analysis". J Am Coll Cardiol. 61 (6): 645–50. doi:10.1016/j.jacc.2012.11.023. PMID 23290543. Unknown parameter
|month=ignored (help) - ↑ De Ambroggi, L.; Sorgente, A.; De Ambroggi, G. "Early repolarization pattern: Innocent finding or marker of risk?". J Electrocardiol. 46 (4): 297–301. doi:10.1016/j.jelectrocard.2013.02.008. PMID 23540936.
- ↑ Patel, RB.; Ng, J.; Reddy, V.; Chokshi, M.; Parikh, K.; Subacius, H.; Alsheikh-Ali, AA.; Nguyen, T.; Link, MS. (2010). "Early repolarization associated with ventricular arrhythmias in patients with chronic coronary artery disease". Circ Arrhythm Electrophysiol. 3 (5): 489–95. doi:10.1161/CIRCEP.109.921130. PMID 20657030. Unknown parameter
|month=ignored (help)