Elsevier

Heart Rhythm

Volume 13, Issue 4, April 2016, Pages 894-902
Heart Rhythm

Benign vs malignant inferolateral early repolarization: Focus on the T wave

https://doi.org/10.1016/j.hrthm.2015.11.020Get rights and content

Background

Inferolateral early repolarization (ER) is highly prevalent and is associated with idiopathic ventricular fibrillation (VF).

Objective

The purpose of this study was to evaluate the potential role of T-wave parameters to differentiate between malignant and benign ER.

Methods

We compared the ECGs of patients with ER and VF (n = 92) with control subjects with asymptomatic ER (n = 247). We assessed J-wave amplitude, QTc interval, T-wave/R-wave (T/R) ratio in leads II and V5, and presence of low-amplitude T waves (T-wave amplitude <0.1 mV and <10% of R-wave amplitude in lead I, II, or V4–V6).

Results

Compared to controls, the VF group had longer QTc intervals (388 ms vs 377 ms, P = .001), higher J-wave amplitudes (0.23 mV vs 0.17 mV, P <.001), higher prevalence of low-amplitude T waves (29% vs 3%, P <.001), and lower T/R ratio (0.18 vs 0.30, P <.001). Logistic regression analysis demonstrated that QTc interval (odds ratio [OR] per 10 ms: 1.15, 95% confidence interval [CI} 1.02–1.30), maximal J-wave amplitude (OR per 0.1 mV: 1.68, 95% CI 1.23–2.31), lower T/R ratio (OR per 0.1 unit: 0.62, 95% CI 0.47–0.81), presence of low-amplitude T waves (OR 3.53, 95% CI 1.26–9.88). and presence of J waves in the inferior leads (OR 2.58, 95% CI 1.18–5.65) were associated with malignant ER.

Conclusion

Patients with malignant ER have a higher prevalence of low-amplitude T waves, lower T/R ratio (lead II or V5), and longer QTc interval. The combination of these parameters with J-wave amplitude and distribution of J waves may allow for improved identification of malignant ER.

Introduction

The electrocardiographic (ECG) pattern of inferolateral early repolarization (ER) is common, with a particularly high prevalence reported among athletes and adolescents.1 An association between inferolateral ER with sudden cardiac arrest has been established by a number of different groups.2 Population-based studies have also reported an increased mortality among patients with inferolateral ER compared to controls.1, 3, 4 Despite the reports linking ER with sudden death, only a small minority of patients with this pattern on the ECG will have sudden cardiac arrest, while the majority remain asymptomatic. The identification of this minority of patients represents a significant challenge. Currently, the identification of the malignant variant of the ER pattern is reliant on parameters such as the J-wave distribution, J-wave amplitude, and ST-segment morphology.5, 6 However, the sensitivity and specificity of these parameters remain limited. Additionally, assessment of ST-segment morphology is difficult. The T wave may provide similar information as the ST-segment morphology measured at 100 ms after the J point, and others have advocated analysis of repolarization markers independently of J-wave amplitude for risk stratification in inferolateral ER.7 Furthermore, the concomitant presence of inferolateral ER and long QT syndrome seems to increase arrhythmic risk.8, 9 In this study, we sought to determine the potential role of T-wave parameters to differentiate malignant and benign forms of inferolateral ER.

Section snippets

Study population

Cases with ER and aborted sudden death were included from the International Registry of Idiopathic Ventricular Fibrillation, which has enrolled ventricular fibrillation (VF) patients from various tertiary care arrhythmia centers since January 2007.2 The diagnosis of idiopathic VF for patients included in the registry is based on the absence of identifiable structural heart disease (normal echocardiography) and detectable coronary artery disease (normal exercise testing or normal coronary

Results

Patients in the VF group were significantly younger than controls (37.1 ± 13.1 years vs 50.4 ± 10.9 years, P <.001). In both groups, the majority were men (75% VF group vs 77% controls; P = .71). Heart rate was significantly higher and QTc interval longer in the VF group compared to controls (Table 1). Of note, although the QTc interval was normally distributed in controls (P = .20 according to the Kolmogorov–Smirnov test), this was not the case in the VF group (P = .007; Figure 2).

Discussion

Patients with malignant inferolateral ER have longer QTc intervals, a higher prevalence of low-amplitude T waves, and lower T/R ratios in leads II and V5 than controls with benign inferolateral ER. These T-wave parameters have superior performance in differentiating malignant from benign inferolateral ER than conventional ECG risk markers such as J-wave distribution, maximal J-wave amplitude, and ST-segment morphology.

Multiple studies have reported that the presence of inferior or a combination

Conclusion

Patients with malignant ER have a higher prevalence of low-amplitude T waves, lower T/R ratio (lead II or V5), and longer QTc interval, which lacks a typical gaussian distribution. Combining these parameters with maximal J-wave amplitude and presence of J waves in the inferior leads may allow for improved identification of malignant ER.

Clinical Perspectives

Inferolateral early repolarization has a high prevalence but is also associated with ventricular fibrillation. Risk stratification remains

Acknowledgments

The following physicians kindly contributed to data collection: Gabriel Laurent (Dijon), Pascal Defaye (Grenoble), Dominique Lacroix (Lille), Maurice Pornin (Paris), Frederic Anselme (Rouen), Patrice Scanu (Caen), Paul Bru (La Rochelle), Nicolas Delarche (Pau), Jean Vidal (Niort), Pascal Chavernac (Castres), Julien Laborderie (Bayonne), Robert Frank (Paris), Dominique Babuty (Tours), Jean-Luc Pasquié (Montpellier), Christian de Chillou (Nancy), Elisabeth Somody (Montauban), Philippe Jarnier

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This work was supported by special grants from the Direction Générale de l’Offre de Soins (PHRC No. 20-12) and through the Investment of the Future Grant ANR-10-IAHU-04 from the government of France through the Agence National de la Recherche.

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