Clinical characteristics and prevalence of early repolarization associated with ventricular arrhythmias following acute ST-elevation myocardial infarction

Prognostic Assessment of Early Repolarization/J Wave Electrocardiographic Pattern in Patients With Stable Ischemic Heart Disease

Recent studies suggested that early repolarization (ER)/J wave at the electrocardiogram (ECG) is associated with increased risk of sudden death and ventricular arrhythmias in patients with acute myocardial infarction. In this study, we prospectively assessed whether ER/J wave has any long-term prognostic implications in patients with stable ischemic heart disease (IHD). We enrolled consecutive clinically stable patients with documented IHD, referred to undergo a routine ECG. ER (typical concave ST-segment elevation) and J wave were diagnosed according to prospectively defined criteria. The final population included 617 patients with documented IHD (455 men; age 68.1 ± 11 years). ER/J wave was found in 138 patients (22.4%), 13 of whom (2.1%) showed ER and 133 (21.6%) a J wave. At a follow-up of 8.1±2.9 years, 160 deaths occurred (25.9%), 60 (9.7%) attributed to cardiovascular causes. Total mortality was lower in patients with versus those without ER/J wave (18.8% vs 28.0%; hazard ratio [HR] 0.61, 95% confidence interval [CI] 0.40 to 0.93, p = 0.02). The difference, however, was not significant after adjustment for confounding clinical variables (HR 0.78, 95% CI 0.51 to 1.19, p = 0.25). No significant difference was found in cardiovascular death between patients with (7.2%) and those without (10.4%) ER/J wave (adjusted HR 0.78, 95% CI 0.40 to 1.55, p = 0.48). Similar results were obtained for ER and J wave separately, and for ECG location of ER/J wave (inferior or lateral/precordial) and type of J wave (notched or slurred). The ER/J wave pattern at the ECG is not associated with increased risk of long-term mortality in clinically stable patients with a documented history of IHD.

Electrocardiography is Useful to Predict Postoperative Ventricular Arrhythmia in Patients Undergoing Cardiac Surgery: A Retrospective Study

Background: Preoperative detection of high-/low-risk postoperative ventricular arrhythmia (POVA) patients using a noninvasive method is an important issue in the clinical setting. This study mainly aimed to determine the usefulness of several preoperative electrocardiographic (ECG) markers in the risk assessment of POVA with cardiac surgery.

Method: We enrolled 1024 consecutive patients undergoing cardiac surgery, and a total of 823 patients were included in the study. Logistic regression analysis determined preoperative ECG markers. A new risk predicting model were developed to predict occurrence of POVA, and the receiver operating characteristic curve (ROC) was used to validate this model.

Results: Of these, 337 patients experienced POVA, and 485 patients did not experience POVA in this retrospective study. Among 15 ECG markers, a univariate analysis found a strong association between POVA and preoperative VA, the R-wave in lead aVR, the QRS wave, index of cardiac electrophysiological balance (iCEB), QT interval corrected (QTc), Tpeak–Tend interval (Tpe) in lead V2, the J wave in the inferolateral leads, pathological Q wave, and SV1+RV5>35 mm. Multivariate analysis showed that a preoperative J wave [adjusted odds ratio (AOR): 3.80; 95% CI: 1.88–7.66; p < 0.001], Tpe >112.5-ms (AOR: 2.80; 95% CI: 1.57–4.99; p < 0.001), and SV1+RV5 >35 mm (AOR: 2.92; 95% CI: 1.29–6.60; p = 0.01) were independently associated with POVA. A new risk predicting model were developed in predicting POVA.

Conclusion: The ECG biomarkers including J wave, Tpe >112.5 ms, and SV1+RV5 >35 mm were significantly predicted POVAs. A risk predicting model developed with electrocardiographic risk markers preoperatively predicted POVAs.

Trelagliptin ameliorates oxygen-glucose deprivation/reperfusion (OGD/R)-induced mitochondrial dysfunction and metabolic disturbance of endothelial cells

Acute myocardial infarction (AMI) is a severe cardiovascular disease with high mortality. It is reported to be closely related to the mitochondrial dysfunction and metabolic disturbance on endothelial cells under a chronic hypoxic state. Significant declined mitochondrial respiration, ATP production, and metabolic changes are the main characteristics of endothelial injury in the disease. Trelagliptin is a DPP-4 inhibitor applied for the treatment of type II diabetes and has been recently reported to exert various pharmacological properties. In this investigation, we examined whether Trelagliptin possessed a protective effect against mitochondrial dysfunction and metabolic disturbance in human aortic valvular endothelial cells (HAVECs) under oxygen-glucose deprivation/reperfusion (OGD/R) conditions. We found that both the cytotoxicity and mitochondrial oxidative stress in HAVECs induced by OGD/R stimulation were greatly alleviated by Trelagliptin. In addition, the declined mitochondrial respiration and ATP production decreased secretion of cystathionine and creatine, and the increased production of triglyceride and adiponectin in OGD/R-challenged HAVECs was dramatically reversed by Trelagliptin, accompanied by the upregulated expression level of PGC-1α and CPT-1. Lastly, the AMPK pathway was observed to be significantly activated in OGD/R-challenged HAVECs by Trelagliptin treatment. After co-administration of the inhibitor of the AMPK pathway, the effects of Trelagliptin on mitochondrial function and metabolic alterations were significantly abolished. Taken together, our data indicate that Trelagliptin ameliorated OGD/R-induced mitochondrial disturbance and metabolic changes by activating the AMPK pathway.

Effect of acute myocardial ischemia on inferolateral early repolarization

BACKGROUND

Inferolateral early repolarization (ER) is associated with an increase in arrhythmic risk, particularly in the presence of myocardial ischemia.

OBJECTIVE

The purpose of this study was to determine the effect of myocardial ischemia on ER.

METHODS

We retrospectively analyzed procedural electrocardiograms (ECGs) of patients with ER undergoing a controlled, 1-minute coronary balloon occlusion for collateral function testing. ECG leads with ER were analyzed immediately before coronary balloon occlusion (PRE), at 60 seconds of coronary balloon occlusion (OCCL), and >30 seconds after balloon deflation.

RESULTS

Seventy-seven patients with ER in the preprocedural ECG (86% inferior, 20% lateral) underwent 135 coronary balloon occlusions during which a J wave was recorded in 224 leads (ER leads). From PRE to OCCL, ST-segment amplitude (ST) in the ER lead increased in 94 cases (44%) from 0.00 ± 0.03 to 0.05 ± 0.06 mV (P < .0001). In this group, J-wave amplitude (JWA) increased from 0.10 ± 0.07 to 0.13 ± 0.09 mV (P < .0001). ST in the ER lead decreased or was unchanged in 121 cases (56%) from PRE to OCCL (from 0.01 ± 0.05 to -0.02 ± 0.04 mV; P < .0001). In this group, JWA decreased from 0.10 ± 0.05 to 0.08 ± 0.07 mV (P < .0001). The change in JWA was related to the change in ST (linear regression analysis; R² = 0.34; P < .0001), while there was no relation between the change in R-wave amplitude and the change in ST (R² = 0.0003; P = .83).

CONCLUSION

During acute ischemia, JWA mirrors ST-segment changes. This may explain increased arrhythmic vulnerability of patients with ER during myocardial ischemia. It also adds weight to the hypothesis of ER being a phenomenon of repolarization.

Prevalence and Significance of an Early Repolarization Electrocardiographic Pattern and Its Mechanistic Insight Based on Cardiac Magnetic Resonance Imaging in Patients With Acute Myocarditis

BACKGROUND

An early repolarization electrocardiographic (ER-ECG) pattern is caused by various pathophysiological conditions and is reported to be a predictor of life-threatening ventricular tachyarrhythmias. However, little evidence has been reported on the prevalence and significance of the ER-ECG pattern in acute myocarditis. This study aimed to investigate the prevalence and significance of the ER-ECG pattern and its mechanistic insight based on the cardiac magnetic resonance findings in patients with acute myocarditis.

METHODS

Thirty patients (23 men; 39.2±19.1 years) with a diagnosis of acute myocarditis by a clinical presentation between March 2011 and April 2018 were retrospectively evaluated. The patients were divided into 2 groups depending on the presence of an ER-ECG pattern on admission.

RESULTS

Nine cases had an ER-ECG pattern, which was defined as terminal QRS notching or slurring with an amplitude of >0.1 mV in at least 2 inferior or lateral leads (early repolarization [ER] group), whereas the remaining 21 cases had broad ST-segment elevation or pathological Q waves (non-ER group). The cardiac troponin T level was significantly higher in the non-ER group than ER group (3.2±4.3 versus 0.9±1.2 ng/mL; P=0.036). The ECG changes returned to baseline along with the normalization of the cardiac biomarkers. Nine of the 21 non-ER group patients, but none of the 9 ER group patients, developed a fulminant course and lethal ventricular tachyarrhythmias. T2-weighted cardiac magnetic resonance showed high-intensity signals over the entire transmural left ventricle in the non-ER group, whereas they were localized to the left ventricular epicardium in the ER group.

CONCLUSIONS

The ER-ECG pattern in acute myocarditis was transient and reversible and was not associated with a worse prognosis. Inflammation/swelling localized to the left ventricular epicardium because of acute myocarditis might provide a mechanistic insight into the ER-ECG pattern.

Early repolarization pattern on ECG recorded before the acute coronary event does not predict ventricular fibrillation during ST-elevation myocardial infarction

BACKGROUND

Generally considered benign, electrocardiographic (ECG) early repolarization (ER) pattern was claimed to be an indicator of increased susceptibility to ventricular arrhythmias during acute ischemia.

OBJECTIVE

The purpose of this study was to assess in a nonselected population whether ER pattern documented before ST-elevation myocardial infarction (STEMI) is associated with risk of hemodynamically unstable ventricular tachycardia (VT) or ventricular fibrillation (VF) during acute STEMI.

METHODS

For STEMI patients admitted for primary percutaneous coronary intervention from 2007-2010, the latest ECGs recorded before STEMI were exported in digital format. After excluding ECGs with paced rhythm and QRS duration ≥120 ms, the remaining ECGs were processed using the Glasgow algorithm allowing automatic ER detection. The association between ER pattern and VT/VF during the first 48 hours of STEMI was tested using logistic regression.

RESULTS

ECGs recorded before STEMI were available for 1584 patients. Of these patients, 124 did not meet inclusion criteria, leaving 1460 patients available for analysis (age 68 ± 12 years; 67% male). ER pattern was present in 272 patients (18.6%; ER+ group). ER+ and ER- groups did not differ with regard to clinical characteristics. VT/VF during the first 48 hours of STEMI occurred in 19 ER+ (7.0%) and 105 ER- patients (8.8%; P = .398). ER was not associated with any VT/VF (odds ratio [OR] 0.78; 95% confidence interval [CI] 0.47-1.29; P = .324); VT/VF before reperfusion (OR 0.48; 95% CI 0.23-1.001; P = .051); or reperfusion-related VT/VF (OR 1.28; 95% CI 0.55-3.01; P = .569).

CONCLUSION

In a nonselected population of STEMI patients, the ER pattern on ECG recorded before the acute coronary event was not associated with VT/VF during the first 48 hours of STEMI.

Electrocardiographic early repolarization is associated with future ventricular arrhythmia after acute myocardial infarction-Systematic Review and Meta-Analysis

BACKGROUND

Early repolarization (ER) has been linked to ventricular arrhythmia (VA) and sudden cardiac death in patients without structural heart disease. We aimed to assess the latest evidence on whether ER is associated with future VA after acute myocardial infarction (AMI).

METHODS

We performed a comprehensive search on the topic that assesses ER and VA/adverse cardiovascular events in AMI. We included studies with sufficient details on ER and VA, we also performed a meta-analysis on their morphology.

RESULTS

A total of 3350 subjects from 9 studies were included. Five hundred and twenty-one (15.55%) had ER and 2829 (84.45%) did not. On meta-analysis, ER (+) in AMI was associated with VA with a pooled odds ratio (OR) of 3.58 (2.70-4.73), P < 0.001; heterogeneity I 2 34%. Subgroup analysis of patients with ST-segment elevation myocardial infarction (STEMI) showed an OR of 2.79 [1.98-3.93], P < 0.001; heterogeneity I 2 0%. Inferior location of ER (+) was associated with VA OR 3.98 [1.86-8.53], P = 0.008; I 2 67%. Notching had a 5.41 [3.52-8.32], P < 0.001; low heterogeneity I 2 0% of having VA. Pooled OR for J-point elevation was 4.72 [2.63-8.46], P < 0.001; I 2 25%. Horizontal ST-segment was associated with VA with an OR of 4.30 [1.89-975], P < 0.001; I 2 59%. Lateral location and slurred morphology were not associated with VA. Upon sensitivity analysis for inferior location and horizontal ST-segment, removal of a study reduces heterogeneity significantly.

CONCLUSION

Early repolarization especially those with the inferior location, notching morphology, an elevated J-point and horizontal ST-segment had a higher likelihood of VA in AMI including STEMI patients.

The Prognostic Value of Early Repolarization Pattern for the Ventricular Tachyarrhythmias of Acute Myocardial Infarction Patients: A Meta-Analysis

Several studies have indicated that early repolarization (ER) is a risk factor for ventricular tachyarrhythmias (VTAs) in acute myocardial infarction (AMI) patients. The prognostic values of ER detail characteristics except J-point morphology, and inferior leads ER location for VTAs are still unclear. We searched PubMed, Embase, and the Cochrane Library for eligible studies up to March 4, 2019. Studies to investigate the relationship between ER and the incidence of VTAs in AMI patients were extracted. A total of 10 studies with 2,672 participants were included in the analysis. ER significantly predicted the incidence of VTAs (odds ratio [OR] 3.62, 95% confidence intervals [CI] 2.77-4.73), regardless of the type of AMI. The presence of ER before AMI (OR 5.58, 95% CI 3.41 to 9.12) and after AMI (OR 3.02, 95% CI 2.19-4.15) increased the risk of VTAs. The prognostic value of ER for VTAs in the long follow-up (≥30 days) (OR 2.39, 95% CI 1.59-3.59) fell by half compared to the short follow-up duration (<30 days) (OR 4.97, 95% CI 3.48-7.09). Patients with ER displayed a higher risk of developing ventricular fibrillation (VF) (OR 6.94, 95% CI 3.87-12.43) than those without ER. However, neither J-point elevation with OR = 2.48 nor lateral leads' ER location with OR = 3.83 remarkably increased the risk of VTAs in patients with AMI. ER is significantly associated with increasing risk of VTAs, particularly VF, in AMI patients. This relationship is weaker in the 30-day follow-up and is not reinforced by J-point elevation and lateral leads' ER location.

Sudden Cardiac Death in Ischemic Heart Disease: Pathophysiology and Risk Stratification

Sudden cardiac death (SCD) accounts for approximately 360,000 deaths annually in the United States. Ischemic heart disease is the major cause of death in the general adult population. SCD can be due to arrhythmic or nonarrhythmic cardiac causes. Arrhythmic SCD may be caused by ventricular tachyarrhythmia or pulseless electrical activity/asystole. This article reviews the most recent pathophysiology and risk stratification strategies for SCD, emphasizing electrophysiologic surrogates of conduction disorder, dispersion of repolarization, and autonomic imbalance. Factors that modify arrhythmic death are addressed.

Associations of Sex Hormones With Surface Electrocardiogram J Point Amplitude in Healthy Volunteers

Gender differences in J point height exist. Previous studies suggest male sex hormones mediate effects on cardiovascular disease through myocardial repolarization. Our objective was to assess whether male and female sex hormones are associated with J point amplitude in healthy subjects. We conducted a cross-sectional study of 475 healthy, mixed racial population of men, and premenopausal women (age 33 ± 9 years, 56% male). Baseline J point amplitude (JPA) was obtained from continuous surface electrocardiograms. Plasma testosterone (T), dihydrotestosterone, estrone, 17-estradiol (E2), and sex hormone-binding globulin were measured. A free testosterone index (FTI) was calculated. Multivariate regression analysis stratified by gender and electrocardiographic lead location was used to determine independent predictors of maximum JPA. Regression analysis demonstrated FTI levels were positively associated with JPA in lateral leads (β = +0.01, p <0.05) in men but not in women. Total testosterone was positively associated with anterior electrocardiographic lead JPA in women (β = +0.5, p <0.02), but not in men. E2 was positively associated with inferior lead JPA (β = +1.2, p <0.03) in men but not in women. Total testosterone levels were positively associated with JPA in anterior leads (β = +0.054, p <0.05) in women. Male volunteers in the highest tertile of FTI demonstrated greater lateral JPA compared with the lowest tertile (p <0.05). Women in the highest tertile of FTI demonstrated greater anterior lead JPA compared with the lowest tertile (p <0.05). In conclusion, in a young, healthy population, the female sex hormone E2 and an FTI are independent determinants of JPA in men, whereas T is associated with JPA in women.

Early repolarization is associated with a significantly increased risk of ventricular arrhythmias and sudden cardiac death in patients with structural heart diseases

BACKGROUND

Early repolarization pattern (ERP) has been proved to increase risk of arrhythmia death in the general population, but its prognostic significance in patients with structural heart disease (SHD) is controversial.

OBJECTIVE

The purpose of this study was to conduct a meta-analysis of studies assessing the association between ERP and risk of ventricular arrhythmias (VTAs) and sudden cardiac death (SCD) in patients with SHD.

METHODS

We performed a literature search using MEDLINE (January 1, 1966, to September 25, 2016) and EMBASE (January 1, 1980, to September 25, 2016) with no restrictions. Studies that reported odds ratio (OR) estimates with 95% confidence intervals (CIs) for the associations of interest were included.

RESULTS

The search yielded 19 observational studies, involving 7268 patients that reported 1127 cases of VTAs or SCD. In the selected studies, the point estimates of the ORs were consistently greater than 1. Compared with those without ERP, patients with ERP experienced a significantly increased risk of developing VTAs or SCD (OR 4.76; 95% CI 3.62-6.26), ventricular fibrillation (OR 7.14; 95% CI 4.31-11.82), and SCD (OR 4.07; 95% CI 1.58-10.51). The results were consistent and statistically significant in all subgroups. ERP with J-point elevation in inferior leads, notching configuration, and horizontal or descending ST segment connote higher risk.

CONCLUSION

ERP is associated with a significant increased risk of VTAs or SCD in patients with SHD. Future research should attempt to understand the exact mechanisms for the arrhythmia risk and to introduce ERP in the risk stratification in this patient group.

Ventricular Arrhythmia after Acute Myocardial Infarction: 'The Perfect Storm'

Ventricular tachyarrhythmias (VAs) commonly occur early in ischaemia, and remain a common cause of sudden death in acute MI. The thrombolysis and primary percutaneous coronary intervention era has resulted in the modification of the natural history of an infarct and subsequent VA. Presence of VA could independently influence mortality in patients recovering from MI. Appropriate risk assessment and subsequent treatment is warranted in these patients. The prevention and treatment of haemodynamically significant VA in the post-infarct period and of sudden cardiac death remote from the event remain areas of ongoing study.

J Waves Are Associated With the Increased Occurrence of Life-Threatening Ventricular Tachyarrhythmia in Patients With Nonischemic Cardiomyopathy

INTRODUCTION

Recent studies showed that J waves were associated with higher incidence of ventricular tachyarrhythmia (VT/VF) in patients with idiopathic ventricular fibrillation (VF) and myocardial infarction. We sought to assess the association between J waves and VT/VF in patients with nonischemic cardiomyopathy (NICM).

METHODS AND RESULTS

We retrospectively enrolled 109 patients (79 men; mean age, 60 ± 15 years) with NICM who underwent implantable cardioverter defibrillator (ICD) implantation. The primary endpoint of this study was the occurrence of appropriate device therapy due to sustained VT/VF. The J wave was electrocardiographically defined as an elevation of the terminal portion of the QRS complex of >0.1 mV in at least 2 contiguous inferior or lateral leads. Among the 109 patients, 37 (34%) experienced an episode of appropriate device therapy during a median follow-up period of 25.9 (IQR 11.5-54.3) months. Kaplan-Meier curves showed that the presence of J waves on the 12-lead ECG obtained before device implantation was associated with an increased occurrence of appropriate device therapy (P < 0.001). Multivariate Cox proportional regression analysis revealed that the presence of J waves (HR 2.95; 95% CI 1.31-6.64; P = 0.009) was an independent predictor for the occurrence of appropriate device therapy. In the subgroup analysis of the patients with dilated or hypertrophic cardiomyopathy, J wave tended to increase the occurrence of appropriate device therapy (P = 0.056 and P = 0.092, respectively).

CONCLUSIONS

The presence of J waves was an independent predictor for the occurrence of appropriate device therapy in patients with NICM who underwent ICD implantation.

New approaches to predicting the risk of sudden death

In this review article, we will explore some of the contemporary methods for predicting sudden cardiac death (SCD). These include experimental methods yet to be adopted in the clinical setting, and methods that have been extrapolated from observational data in those with a history of SCD. We will discuss how these relate to the different aetiologies and disease processes. We will also explore how these may be used in the clinical setting to decide on management.

Notching early repolarization pattern in inferior leads increases risk of ventricular tachyarrhythmias in patients with acute myocardial infarction: a meta-analysis

The aim of this of this meta-analysis was to examine the potential association between certain early repolarization (ER) characteristics and ventricular tachyarrhythmias (VTAs) in patients with acute myocardial infarction (AMI). We searched PubMed, Embase and Web of Science databases for records published until December 2014. Of the 658 initially identified records, 7 studies with a total of 1,565 patients (299 with ER and 1,266 without ER) were finally analyzed. Overall, patients with ER displayed a higher risk of VTAs following AMI compared to patients without ER [odds ratio (OR): 3.75, 95% CI: 2.62–5.37, p < 0.00001]. Subgroup analyses showed that the diagnosis of ER prior to AMI onset is a better predictor of VTAs (OR: 5.70, p < 0.00001) compared to those diagnosed after AMI onset (OR: 2.60, p = 0.00001). Remarkably, a notching morphology was a significant predictor of VTAs compared to slurring morphology (OR: 3.85, p = 0.002). Finally, an inferior ER location (OR: 8.85, p < 0.00001) was significantly associated with increased risk of VTAs in AMI patients. In conclusion, our meta-analysis suggests that ER pattern is associated with greater risk of VTAs in patients with AMI. A notched ER pattern located in inferior leads confers the highest risk for VTAs in AMI.

Difference in the Clinical Characteristics of Ventricular Fibrillation Occurrence in the Early Phase of an Acute Myocardial Infarction Between Patients With and Without J Waves

INTRODUCTION

We recently showed that the presence of J waves increases the risk of ventricular fibrillation (VF) occurrence in the early phase of an acute myocardial infarction (AMI). This study aimed to evaluate the clinical characteristics of VF occurrences in the early phase of an AMI between patients with and without J waves.

METHODS AND RESULTS

This retrospective, observational study included 281 consecutive patients with an AMI (69 ± 12 years; 207 men) in whom 12-lead ECGs before AMI onset could be evaluated. The patients were classified based on a VF occurrence <48 hours after AMI onset and the presence of J waves. J waves were electrocardiographically defined as an elevation of the terminal portion of the QRS complex of >0.1 mV from baseline in at least 2 contiguous inferior or lateral leads. VF occurred in 24 patients, and J waves were present in 37. VF occurrence was more prevalent in the patients with than without J waves (27% vs. 6%; P < 0.001). Among the 244 patients without J waves, peak creatine kinase level (P < 0.01), number of diseased coronary arteries (P < 0.01), and male sex (P < 0.05) were higher in the patients with than without VF occurrence. However, among the 37 patients with J waves, there was no significant difference in these variables. There was no association between the location of J waves and the infarct area.

CONCLUSIONS

In patients with AMI, those with J waves were more likely to develop VF and less likely to have high-risk clinical characteristics than those without J waves.

Predictors of ventricular fibrillation at reperfusion in patients with acute ST-elevation myocardial infarction treated by primary percutaneous coronary intervention

Ventricular fibrillation (VF) during reperfusion (rVF) in ST-segment elevation myocardial infarction (STEMI) is an infrequent but serious event that complicates coronary interventions. The aim of this study was to analyze clinical predictors of rVF in an unselected population of patients with STEMI treated with percutaneous coronary intervention (PCI). Consecutive patients with STEMI admitted to a tertiary care hospital for primary PCI from 2007 to 2012 were retrospectively assessed for the presence of rVF. Admission electrocardiograms, stored in a digital format, were analyzed for a maximal ST-segment elevation in a single lead and the sum of ST-segment deviations in all leads. Clinical, electrocardiographic, and angiographic characteristics were tested for associations with rVF using logistic regression analysis. Among 3,724 patients with STEMI admitted from 2007 to 2012, 71 (1.9%) had rVF. In univariate analysis, history of myocardial infarction, aspirin and β-blocker use, VF before PCI, left main coronary artery disease, inferior myocardial infarction localization, symptom-to-balloon time <360 minutes, maximal ST-segment elevation in a single lead >300 μV, and sum of ST-segment deviations in all leads >1,500 μV were associated with increased risk for rVF. In a multivariate analysis, sum of ST-segment deviations in all leads >1500 μV (odds ratio 3.7, 95% confidence interval 1.45 to 9.41, p = 0.006) before PCI remained an independent predictor of rVF. In-hospital mortality was 18.3% in the rVF group and 3.3% in the group without VF (p <0.001), but rVF was not an independent predictor of in-hospital death. In conclusion, the magnitude of ST-segment elevation before PCI for STEMI independently predicts rVF and should be considered in periprocedural arrhythmic risk assessment. Despite higher in-hospital mortality in patients with rVF, rVF itself has no independent prognostic value for prognosis.

Prognostic value of automatically detected early repolarization

Early repolarization associated with sudden cardiac death is based on the presence of >1-mm J-point elevations in inferior and/or lateral leads with horizontal and/or downsloping ST segments. Automated electrocardiographic readings of early repolarization (AER) obtained in clinical practice, in contrast, are defined by ST-segment elevation in addition to J-point elevation. Nonetheless, such automated readings may cause alarm. We therefore assessed the prevalence and prognostic significance of AER in 211,920 patients aged 18 to 75 years. The study was performed at a tertiary medical center serving a racially diverse urban population with a large proportion of Hispanics (43%). The first recorded electrocardiogram of each individual from 2000 to 2012 was included. Patients with ventricular paced rhythm or acute coronary syndrome at the time of acquisition were excluded from the analysis. All automated electrocardiographic interpretations were reviewed for accuracy by a board-certified cardiologist. The primary end point was death during a median follow-up of 8.0 ± 2.6 years. AER was present in 3,450 subjects (1.6%). The prevalence varied significantly with race (African-Americans 2.2%, Hispanics 1.5%, and non-Hispanic whites 0.9%, p <0.01) and gender (male 2.4% vs female 0.6%, p <0.001). In a Cox proportional hazards model controlling for age, smoking status, heart rate, QTc, systolic blood pressure, low-density lipoprotein cholesterol, body mass index, and coronary artery disease, there was no significant difference in mortality regardless of race or gender (relative risk 0.98, 95% confidence interval 0.89 to 1.07). This was true even if J waves were present. In conclusion, AER was not associated with an increased risk of death, regardless of race or gender, and should not trigger additional diagnostic testing.

Clinical characteristics and outcomes associated with the natural history of early repolarization in a young, biracial cohort followed to middle age: the Coronary Artery Risk Development in Young Adults (CARDIA) study

BACKGROUND

Early repolarization (ER), a common electrocardiographic phenotype, has been associated with increased mortality risk in middle-aged adults. Data are sparse on long-term follow-up and outcomes associated with ER in younger adults.

METHODS AND RESULTS

We prospectively examined 5039 participants (mean age, 25 years at baseline, 40% black) from the Coronary Artery Disease Risk in Adults (CARDIA) cohort for 23 years. Twelve-lead ECGs were recorded and analyzed at years 0, 7, and 20 and coded as definite or probable ER using a standardized algorithm. Cox regression was used, and models were adjusted for important baseline and clinical covariates. Kaplan-Meier curves were created for presence of ER and total mortality and cardiovascular mortality. Participants with ER were more likely to be black, male, smoke, have higher systolic blood pressure, lower heart rate and body mass index, higher exercise duration, and longer PR, QRS, and QT intervals. ER was associated with total mortality (hazard ratio, 1.77; confidence interval, 1.38-2.28; P<0.01) and cardiovascular mortality (hazard ratio, 1.59; confidence interval, 1.01-2.50; P=0.04) in unadjusted analyses, but adjustment for age, sex, and race attenuated associations almost completely. Sex-race stratified analyses showed no significant associations between ER and outcome for any of the subgroups except blacks.

CONCLUSIONS

The presence of ER at any time point during 23 years of follow-up was not associated with adverse outcomes. Black race and male sex confound the unadjusted association of ER and outcomes, with no race-sex interactions noted. Additional studies are necessary to understand the factors associated with heightened risk of death in those who maintain ER into and beyond middle age.

Transient and rapid QRS-widening associated with a J-wave pattern predicts impending ventricular fibrillation in experimental myocardial infarction

BACKGROUND

Certain types of the early repolarization phenomenon, previously considered to be benign, have been reported to be associated with ventricular fibrillation (VF), both in population-based studies and in the myocardial infarction (MI) settings.

OBJECTIVE

To analyze whether QRS widening and appearance of a J-wave pattern in experimental MI settings is predictive of VF.

METHODS

MI was induced in 32 pigs by 40-minute inflation of an angioplasty balloon in the left descending artery, and electrocardiogram was continuously recorded. Multilead QRS boundaries were computed, and QRS duration was calculated on a beat-to-beat basis during the occlusion period for each pig. An association between QRS widening and subsequent VF was studied using receiver operating characteristic curve analysis. Electrocardiograms at maximum QRS duration were reviewed for the presence of a J-wave pattern.

RESULTS

Sixteen animals had VF episodes during the occlusion period. Two peaks of QRS widening were found in all animals: the first peak immediately on left descending artery occlusion and the second peak 19.1 ± 4.0 minutes later. The magnitude of changes in the QRS width over time had significant interindividual differences. A QRS widening of ≥28 ms during a 3-minute time window was observed in 14 animals and predicted impending VF (selectivity 80%, specificity 73%, positive predictive value 57%, and negative predictive value 89%; P = .008). In 10 of 14 (71%) pigs, a J-wave pattern appeared at maximal QRS duration. The appearance of a J-wave pattern predicted VF with selectivity 80%, specificity 68%, positive predictive value 53%, and negative predictive value 88% (P = .02).

CONCLUSION

Transient QRS widening, commonly associated with a J-wave pattern, appears to predict impending VF in acute ischemia settings and motivates further clinical studies for monitoring immediate risk of VF in MI.

Presence of early repolarization on admission electrocardiography is associated with long-term mortality and MACE in patients with STEMI undergoing primary percutaneous intervention

BACKGROUND

Early repolarization (ER) is associated with increased risk of sudden cardiac death and ventricular fibrillation (VF) in patients with/without structural heart disease. In this trial we examined the short- and long-term prognostic value of ER on admission electrocardiogram (ECG) in patients with ST-elevation myocardial infarction (STEMI) treated with primary percutaneous coronary intervention (PCI).

METHOD

Consecutive 521 patients with acute STEMI who underwent primary PCI were enrolled prospectively. Twelve-lead ECGs obtained during the initial diagnosis were scanned and stored digitally. The leads showing the typical ST segment elevation due to the acute infarction were excluded and the remaining ECG leads were included in the analysis for the presence of ER.

RESULTS

The study group included 61 STEMI patients (55 male; mean age 57.6±12.6 years) with ER and 460 STEMI patients (378 male; mean age 57.1±12.5) without ER on ECG. In the ER group, 14 patients (22.9%) had notching, 10 patients (16.4%) had slurring, and 37 patients (60.7%) had only J-point elevation. When analyzing regional leads, ER was observed mostly in inferior leads (n=40, 65.6%). During the hospitalization period, ventricular tachycardia or VF occurred more frequently in the ER group (19.6% vs. 10.9%; p=0.04) and 6 patients (6.9%) from the ER group and 14 patients (3%) from the control group died (p=0.01). During a follow-up period of 21.1±10.2 months, mortality was significantly higher in the ER group (12.7% vs. 4.2%; p=0.01). When total mortality rates were considered, highest mortality was observed in patients with notching pattern (5/14 subjects; 35.7%) when compared to patients with slurring (3/10 subjects; 30%), patients with only J-point elevation patterns (5/37subjects; 13.5%) and the control group (33/460 subjects; 7.1%). Presence of notching and slurring pattern on admission ECG was found as independent predictors of long-term mortality; whereas presence of only J-point elevation was not.

CONCLUSION

Presence of ER pattern in admission ECG in patients with STEMI is associated with both in-hospital and long-term mortality.

Early repolarization syndrome: electrocardiographic signs and clinical implications

Early repolarization syndrome (ERS) was previously considered as a benign variant, but it has recently emerged as a risk marker for idiopathic ventricular fibrillation (VF) and sudden death. As measured by electrocardiogram (ECG), early repolarization is characterized by an elevation of the J point and/or ST segment from the baseline by at least 0.1 mV in at least two adjoining leads. In particular, early repolarization detected by inferior ECG leads was found to be associated with idiopathic VF and has been termed as ERS. This condition is mainly observed in young men, athletes, and blacks. Also, it has become evident that electrocardiographic territory, degree of J-point elevation, and ST-segment morphology are associated with different levels of risk for subsequent ventricular arrhythmia. However, it is unclear whether J waves are more strongly associated with a depolarization abnormality rather than a repolarization abnormality. Several clinical entities can cause ST-segment elevation. Therefore, clinical and ECG data are essential for differential diagnosis. At present, the data set is insufficient to allow risk stratification in asymptomatic individuals. ERS, idiopathic VF, and Brugada syndrome (known as J-wave syndromes) are three clinical conditions that share many common ECG features; however, their clinical consequences are remarkably different. This review summarizes the current electrocardiographic data concerning ERS with clinical implications.

Noncoronary ST elevation and polymorphic ventricular tachycardia during left-sided accessory pathway ablation

INTRODUCTION

An early repolarization (ER) pattern on electrocardiogram (ECG) sometimes has the risk of polymorphic ventricular tachycardia (PVT) or ventricular fibrillation (VF). An abnormal ER pattern can develop in various experimental or clinical situations. We experienced 4 cases of abnormal ER pattern with or without PVT during the radiofrequency (RF) ablation of the left accessory pathway.

METHODS AND RESULTS

An electrophysiologic study and RF ablation were performed in 4 patients. Four patients had atrioventricular reentrant tachycardia. During RF ablation of the left accessory pathway, severe chest pain developed and was followed by abnormal J-point elevation. During the ongoing chest pain and J-point elevation, coronary angiograms showed normal findings. The chest pain and J-point elevation were followed by PVT or VF that was unresponsive to defibrillation. The PVT was spontaneously terminated and repeated. After 0.5 mg atropin was given, chest pain and ECG change disappeared.

CONCLUSION

The mechanisms of ER syndrome during RF ablation might be increased vagal tone due to chest pain or direct vagal stimulation.

[Early repolarisation. A dilemma of risk stratification]

Early repolarization, involving infero-lateral ST segment elevation and prominent J waves at the QRS-ST junction has been considered a normal ECG variant for more than 80 years. More recent studies suggest that this phenomenon is not as benign as earlier believed and may represent a risk for subsequent ventricular fibrillation in patients with and without structural heart disease. However, based on current data it seems unjustified to consider these often accidental ECG findings a marker for high risk of sudden cardiac death. The concept of a reduced repolarization reserve developed for the Long QT syndrome can be transformed to early repolarization syndrome. In general a "fibrillation reserve" is relatively high but if triggers such as a genetic background, age, gender, influences of the autonomous nervous system, changes in body temperature, or an acute coronary syndrome act together ventricular fibrillation may occur. A combination of an "early repolarization ECG" with syncope and/or a positive family history of sudden cardiac death may justify defibrillator therapy just on an individual basis. This review intends to summarize actual aspects of early repolarizations syndrome and focuses on the dilemma of risk stratification.

Idiopathic ventricular fibrillation, early repolarization and other J wave-related ventricular fibrillation syndromes: from an electrocardiographic enigma to an electrophysiologic dogma

Current clinical and experimental data demonstrate that the electrocardiographic J wave plays a critical role in the pathogenesis of ventricular fibrillation (VF) in patients with Brugada syndrome (BS) and early repolarization (ER) syndrome (ERS). This has generated renewed interest in the presence of J waves and ERS in the general population, yet the identification of high-risk ECG markers and the risk stratification of subjects with ERS remain to be established. More recently, this concept has been expanded to VF mechanisms in patients with structural heart diseases. Some of the fatal arrhythmias in the setting of acute myocardial ischemia or infarction may share a similar, J wave-related electrophysiologic process. In canine arterially perfused wedge preparations, the occurrence of J wave-related arrhythmias is mediated by phase 2 reentry. The stability of the action potential (AP) dome in the ventricular epicardium is dependent on the prominence of the AP phase 1 notch. The ability to maintain the AP dome depends on a delicate balance between inward and outward ionic currents during depolarization and the early phase of repolarization. Outward shifts of the balance and inability to maintain the AP dome result in marked dispersion of repolarization and vulnerability to VF. This review describes the electrocardiographic and clinical features of the J waves in idiopathic VF and other structural heart diseases.