Clinical implications of isolated T wave inversion in adults: electrocardiographic differentiation of the underlying causes of this phenomenon

High-Sensitivity Troponin I Assay for Differential Diagnosis of New-Onset Myocardial Infarction in Patients with Acute Decompensated Heart Failure

PURPOSE

Acute decompensated heart failure (ADHF) caused by ischemic heart disease is associated with higher mortality and requires immediate diagnosis. Recently, novel methods to diagnose non-ST elevation myocardial infarction (NSTEMI) using high-sensitivity cardiac troponin have been applied. We compared the clinical utility of high-sensitivity troponin I (hS-TnI), delta troponin I, and other traditional methods to diagnose NSTEMI in patients with ADHF.

MATERIALS AND METHODS

This retrospective cross-sectional study was conducted to analyze patients with ADHF who underwent hS-TnI evaluation of 0-2-h protocol in our emergency department. Patients were grouped according to a diagnosis of NSTEMI.

RESULTS

A total of 524 ADHF [ADHF with NSTEMI, n=109 (20.8%)] patients were enrolled in this analysis. The mean values of hS-TnI (ng/mL) in the ADHF with and without NSTEMI groups were 2.44±5.60 and 0.25±0.91, respectively. Multivariable analysis revealed that regional wall-motion abnormality, T-wave inversion/hyperacute T wave, and initial and delta hS-TnI were predictive factors for NSTEMI. Laboratory values related to cardiac biomarkers, including hS-TnI [odds ratio (OR) (95% confidence interval, CI): 2.18], and the delta hS-TnI [OR (95% CI): 1.55] were significant predictors of NSTEMI. Moreover, receiver operating characteristic analysis showed that the areas under receiver operating characteristic curves for electrocardiographic abnormalities, initial hS-TnI, and delta hS-TnI were 0.794, 0.802, and 0.773, respectively.

CONCLUSION

For diagnosis of suspected NSTEMI in patients with ADHF, initial hS-TnI assay has similar predictive value as ischemic changes on electrocardiogram and superior predictive value than delta hS-TnI calculated by the 0-2-h protocol.

ECG changes and markers of increased risk of arrhythmia in patients with myocardial bridge

BACKGROUND

The clinical significance and prognosis of myocardial bridge (MB) is still a matter of debate.

OBJECTIVES

To assess the novel ECG markers of T peak-to-end (Tp-e) interval, transmural dispersion of repolarization (TDR), is assessed by Tp-e/QT ratio, and index of electrophysiogical index(iCEB),is defined by QT/QRS ratio and changes (ST-T changes) in MB patients.

PATIENTS AND METHODS

Forty one patients who were diagnosed as having MB (MB group) and other 41 patients without MB (non-MB group) at multi-detector CT (MDCT) exam matched by age, sex were enrolled in the study.

RESULTS

iCEB was significantly increased in MB group in comparison to non-MB group particularly in patients with no coronary atherosclerosis (5.3 Vs 4.5, p = 0.04). Tp-e and TDR values were decreased in MB in comparison to non-MB patients particularly in patients with coronary atherosclerosis (69 Vs 80, p = 0.003 and 0.18 Vs 0.2, p = 0.01 respectively). Isolated T inversion in V1 was observed more in MB compared to non-MB patients (58% Vs 5%, p ≤ 0.0001) particularly in patients without coronary atherosclerosis.

CONCLUSION

MB patients have shown decreased Tp-e and TDR markers particularly in MB patients with coronary atherosclerosis.

An Electrocardiogram-Based Risk Equation for Incident Cardiovascular Disease From the National Health and Nutrition Examination Survey

Importance

Electrocardiography (ECG) may detect subclinical cardiovascular disease (CVD) in asymptomatic individuals, but its role in assessing adverse events beyond traditional risk factors is not clear. Interval and vector data that are commonly available on modern ECGs may offer independent prognostic information that improves risk classification.

Objectives

To derive and validate a CVD risk equation based on ECG metrics and to determine its incremental benefit in addition to the Framingham risk score (FRS).

Design, Setting, and Participants

This study included 3640 randomly selected community-based adults aged 40 to 74 years without known CVD from the First National Health and Nutrition Examination Survey (NHANES I) cohort (1971-1975) and 6329 from the NHANES III cohort (1988-1994). Participants were sampled from across the United States. A risk score to assess incident nonfatal and fatal CVD events was derived based on computer-generated ECG data, including frontal P, R, and T axes; heart rate; and PR, QRS, and QT intervals from NHANES I. The most prognostic variables, along with age and sex, were incorporated into the NHANES ECG risk equation. The equation was evaluated in the NHANES III cohort for an independent validation. Follow-up in the NHANES III cohort was completed on December 31, 2006. Data for this study were analyzed from August 11, 2015, to May 20, 2016.

Main Outcomes and Measures

The primary end point was CVD death. Secondary outcomes included 10-year ischemic heart disease and all-cause death.

Results

The final study sample included 9969 participants (4714 men [47.3%]; 5255 women [52.7%]; mean [SD] age, 55.3 [10.1] years) from both cohorts. Frontal T axis, heart rate, and heart rate-corrected QT interval were the most significant ECG factors in the NHANES I cohort. In the validation cohort (NHANES III), the equation provided for prognostic information for fatal CVD with a hazard ratio (HR) of 3.23 (95% CI, 2.82-3.72); the C statistic was 0.79 (95% CI, 0.76-0.81). When added to the FRS in Cox proportional hazards regression models, the categorical (1%, 5%, and 10% cutoffs) net reclassification improvement was 24%. When the FRS and ECG scores were combined in a single model, the C statistic improved by 0.04 (95% CI, 0.02-0.06) to 0.80 (95% CI, 0.77-0.82). Similar improvements were noted when the ECG score was added to the pooled cohort equation. When the equation for prognostic information about ischemic heart disease and all-cause death was evaluated, the results were similar.

Conclusions and Relevance

An ECG risk score based on age, sex, heart rate, frontal T axis, and QT interval assesses the risk for CVD and compares favorably with the FRS alone in an independent cohort of asymptomatic individuals. Although the ECG risk equation is low cost, further research is needed to ascertain whether this additional step in risk stratification may improve prevention efforts and reduce CVD events.

Clinical implications of T-wave inversion in an asymptomatic population undergoing annual medical screening (from the Korean Air Forces Electrocardiogram Screening)

This study aimed to determine prevalence, differentiate underlying causes, and identify the benign group in subjects with asymptomatic T-wave inversion (TWI). We retrospectively read 12-lead electrocardiograms from 3,929 consecutive asymptomatic men in the air force (3,929 participants, mean age 39.3 ± 8.7 years) who underwent medical screening at the Aerospace Medical Center, Korea, from September 2010 to August 2012. TWIs other than in right precordial leads (V1 and V2) were present in 23 men (0.6%). All subjects with persistent TWI for 1 year (n = 18) underwent additional study, with the exception of 1 patient who refused further evaluation. Of 17 subjects with investigated persistent TWI, 8 (47.1%) had an apically displaced papillary muscle, 5 (29.4%) exhibited idiopathic TWI, 3 (17.6%) had apical hypertrophic cardiomyopathy, and 1 (5.9%) had Maron type 2 hypertrophic cardiomyopathy with dynamic left ventricular outflow obstruction. The depth of TWI was significantly shallow in the benign group (idiopathic TWI, 1.6 ± 0.5 mm) compared with potentially nonbenign group (the others; 5.5 ± 3.3 mm, p = 0.021). Lateral lead TWI was significantly correlated with potentially nonbenign group (46% vs 0%, p = 0.049). In conclusion, asymptomatic TWI is not rare (0.6%), even in a healthy population such as Korean Air Force society, and at least 29.4% of subjects with TWI are considered to belong to the benign group that does not require aggressive evaluation and criteria of TWI ≤2 mm other than lateral leads without co-morbidity could help to distinguish the benign group from the potentially nonbenign group.

Prevalence and prognostic significance of T-wave inversions in right precordial leads of a 12-lead electrocardiogram in the middle-aged subjects

BACKGROUND

T-wave inversion in right precordial leads V(1) to V(3) is a relatively common finding in a 12-lead ECG of children and adolescents and is infrequently found also in healthy adults. However, this ECG pattern can also be the first presentation of arrhythmogenic right ventricular cardiomyopathy. The prevalence and prognostic significance of T-wave inversions in the middle-aged general population are not well known.

METHODS AND RESULTS

We evaluated 12-lead ECGs of 10 899 Finnish middle-aged subjects (52% men, mean age 44 ± 8.5 years) recorded between 1966 and 1972 for the presence of inverted T waves and followed the subjects for 30 ± 11 years. Primary end points were all-cause mortality, cardiac mortality, and arrhythmic death. T-wave inversions in right precordial leads V(1) to V(3) were present in 54 (0.5%) of the subjects. In addition, 76 (0.7%) of the subjects had inverted T waves present only in leads other than V(1) to V(3). Right precordial T-wave inversions did not predict increased mortality (not significant for all end points). However, inverted T waves in leads other than V(1) to V(3) were associated with an increased risk of cardiac and arrhythmic death (P<0.001 for both).

CONCLUSIONS

T-wave inversions in right precordial leads are relatively rare in the general population, and are not associated with adverse outcome. Increased mortality risk associated with inverted T waves in other leads may reflect the presence of an underlying structural heart disease.

Diagnostic Value of Electrocardiographic T Wave Inversion in Lead aVL in Diagnosing Coronary Artery Disease in Patients with Chronic Stable Angina

OBJECTIVES

The clinical value of T wave inversion in lead aVL in diagnosing coronary artery disease (CAD) remains unclear. This study aims to investigate the correlation between aVL T wave inversion and CAD in patients with chronic stable angina.

METHODS

Electrocardiograms (ECGs) of 257 consecutive patients undergoing coronary angiography were analyzed. All patients had chronic stable angina. All patients with secondary T wave inversion had been excluded (66 patients). The remaining 191 patients constituted the study population. Detailed ECG interpretation and coronary angiographic findings were conducted by experienced cardiologists.

RESULTS

T wave inversion in aVL was identified in 89 ECGs (46.8%) with definite ischemic Q-ST-T changes in different leads in 97 ECGs (50.8%). Stand alone aVL T wave inversion was found in 27 ECGs (14.1%) while ischemic changes in other leads with normal aVL were identified in 36 ECGs (18.8%). The incidence of CAD was 86.3%. Single, two- and multi-vessel CAD were found in 38.8%, 28.5% and 32.7% of cases respectively. The prevalence of left main, left anterior descending, left circumflex and right coronary arteries were 4.7%, 61.2%, 29.3% and 44.5%, respectively. T wave inversion in aVL was found to be the only ECG variable significantly predicting mid segment left anterior descending artery (LAD) lesions (Odds Ratio 2.93, 95% Confidence Interval 1.59-5.37, p=0.001).

CONCLUSION

This study provides new information relating to T wave inversion in lead aVL to mid segment LAD lesions. Implication of this simple finding may help in bedside diagnosis of CAD typically mid LAD lesions. However, further studies are needed to corroborate this finding.

Predictive value of T-wave abnormalities at the time of emergency department presentation in patients with potential acute coronary syndromes

OBJECTIVES

T-wave abnormalities on electrocardiograms (ECGs) are common, but their ability to predict 30-day cardiovascular outcomes at the time of emergency department (ED) presentation is unknown. The authors determined the association between T-wave abnormalities on the presenting ECG and cardiovascular outcomes within 30 days of presentation in patients with potential acute coronary syndromes (ACSs).

METHODS

This was a secondary analysis of a prospective cohort study of ED patients that presented with a potential ACS. Patients were excluded if they had a prior myocardial infarction, ST-segment elevation or depressions, right or left bundle branch block, or Q-waves on the initial ECG. Data included demographics, medical and cardiac history, and ECG findings including the presence or absence of T-wave flattening, inversions of 1-5 mm, and inversions >5 mm. Investigators followed the hospital course for admitted patients, and 30-day follow-up was performed on all patients. The main outcome was a composite of death, acute myocardial infarction, revascularization, coronary stenosis greater than 50%, or a stress test with reversible ischemia.

RESULTS

Of 8,298 patient visits, 5,582 met criteria for inclusion: 4,166 (74.6%) had no T-wave abnormalities, 721 (12.9%) had T-wave flattening in two or more leads, 659 (11.8%) had T-wave inversions of 1-5 mm, and 36 (0.64%) had T-wave inversions >5 mm. The composite endpoint was more common in patients with T-wave flattening (8.2% vs. 5.7%; p = 0.0001; relative risk [RR] = 1.4; 95% confidence interval [CI] = 1.1 to 1.9), T-wave inversions 1-5 mm (13.2% vs. 5.7%; p = 0.0001; RR = 2.4; 95% CI = 1.8 to 3.1), and T-wave inversions >5 mm (19.4% vs. 5.7%; p = 0.0001; RR = 3.4; 95% CI = 1.7 to 6.1), or any T-wave abnormality (10.8% vs. 5.7%; p = 0.0001; RR = 1.9; 95% CI = 1.6 to 2.3), even after adjustment for initial troponin. This association also existed in the subset of patients without known coronary artery disease.

CONCLUSIONS

In patients with potential ACS presenting to the ED, T-wave abnormalities are associated with higher rates of 30-day cardiovascular events.

T-vector direction differentiates postpacing from ischemic T-wave inversion in precordial leads

BACKGROUND

Postpacing precordial T-wave inversion (TWI), known as cardiac memory (CM), mimics ischemic precordial TWI, and there are no established ECG criteria that adequately distinguish between the two. On the basis of CM properties (postpacing sinus rhythm T vector approaching the direction of the paced QRS vector), we hypothesized that CM induced by right ventricular pacing would manifest a TWI pattern different from that of precordial ischemic TWI, thereby discriminating between the two.

METHODS AND RESULTS

T-wave axis, polarity, and amplitude on a 12-lead ECG during sinus rhythm were compared between CM and ischemic patients. The CM group incorporated 13 patients who were paced in DDD mode with short atrioventricular delay for 1 week after elective pacemaker implantation. The ischemic group consisted of 47 patients with precordial TWI identified among 228 consecutive patients undergoing percutaneous coronary intervention for an acute coronary syndrome. The combination of (1) positive T(aVL), (2) positive or isoelectric T(I), and (3) maximal precordial TWI>TWI(III) was 92% sensitive and 100% specific for CM, discriminating it from ischemic precordial TWI.

CONCLUSIONS

CM induced by right ventricular pacing results in a distinctive T-vector pattern that allows discrimination from ischemic precordial T-wave inversions regardless of the coronary artery involved.

Prehospital 80-LAD mapping: Does it add significantly to the diagnosis of acute coronary syndromes?

Early detection of acute myocardial infarction (MI) is vital in the management of acute coronary syndromes (ACS). Hence we compared the diagnostic capability of the standard 12-lead electrocardiogram (ECG) with the 80-lead ECG body surface map (BSM) prehospital.

METHODS

Consecutive patients (n = 294) presenting prehospital with ischemic type chest pain were included. All had an ECG and BSM pretreatment and a baseline and 12-hour cardiac troponin-T or I (cTnT or cTnI). Acute MI was defined as cTnT > 0.09 or cTnI > 0.1 ng/mL. Acute MI on the BSM was defined as ST elevation measured at the J-point, > or = 1 mm inferior/right ventricular/high right anterior/lateral regions, > or = 2 mm anterior region, > or = 0.5 mm posterior region.

RESULTS

Acute MI occurred in 182/294 (62%) based on cTnT or I. ST elevation on the standard ECG predicted acute MI in 103 (sensitivity 57%, specificity 94%; c-statistic 0.73). The optimal model for the standard ECG included ST elevation, summed ST depression and past history of MI (c-statistic 0.82; Chi-square (Wald) 120.7, 3df). The BSM predicted acute MI in 146 (sensitivity 80%, specificity 92%; c-statistic 0.86). The optimal model for the BSM included BSM criteria for acute MI and past history of MI (c-statistic 0.91; Chi-square (Wald) 180.3, 2df).

CONCLUSION

The 80-lead BSM is superior to the standard 12-lead ECG in predicting acute MI prehospital.

Postoperative death in a patient with unrecognized arrhythmogenic right ventricular dysplasia syndrome

Arrhythmogenic right ventricular dysplasia is an inherited disease causing fatty replacement of heart tissue. This disease often presents as T-wave inversion in the anterior leads of the electrocardiogram (ECG) with life-threatening ventricular arrhythmias. In older patients, progressive right and left ventricular failure can develop. This is a case report of postoperative death occurring in a 59-yr-old woman with undiagnosed arrhythmogenic right ventricular dysplasia after hepatic cystectomy. The patient had T-wave inversion in the inferior ECG leads and no history of arrhythmias. During general anesthesia, cardiovascular collapse occurred in the absence of arrhythmias that was unresponsive to resuscitation.

ECG variable cine: computer program for presentation of temporal changes in ECG variables over different number of ECG leads

The analysis of exercise electrocardiogram (ECG) is based on the alteration of the measured variables in the detection of coronary artery disease (CAD). In its existing form the analysis of the exercise ECG is laborious and requires much time. The temporal analysis of the ECG variable and the comparison between different phases of the exercise test is difficult and time consuming, especially the simultaneous examination of the variables over several leads. In this article we present a computer program, ECG Variable Cine, for the visualization of the temporal changes of values of exercise ECG variables over the selected ECG lead system. The program includes the stationary 3-D presentation for the variables' alteration simultaneously in all selected leads over the time of exercise test. In addition, the program determines two parameters; the average value of the variable over the selected leads at every sample moment, and the chronotropic index, a parameter that indicates heart rate response to exercise. According to the results the average value of ST-segment deviation at the end of the exercise over the leads and chronotropic index are clinically more competent than the maximum value of ST-segment depression in the detection of CAD.

Reversible myocardial contraction abnormalities in patients with an acute noncardiac illness

STUDY OBJECTIVES

Reversible myocardial contraction abnormalities are usually observed in patients with acute ischemic syndromes caused by coronary artery disease. In this study, we report the occurrence of reversible anterior-apical contraction abnormalities in patients with an acute noncardiac illness.

SETTING

This was a retrospective study of 22 patients with the following characteristics: (1) hospitalization for an acute noncardiac illness; (2) appearance of deep T-wave inversion in the precordial leads of the ECG; and (3) presence of an anterior wall motion abnormality on an echocardiogram. Standard clinical information was collected together with results of serial ECGs, echocardiograms, and coronary angiograms.

RESULTS

The primary diagnoses for the 22 acutely ill patients included CNS injury (n=6); sepsis (n=3); acute pulmonary disease (n=3); drug overdose or metabolic abnormality (n=7); and post noncardiac surgery (n=3). An initial echocardiogram revealed an anterior apical wall motion abnormality. At follow-up, all patients had progressive improvement in anterior wall motion with return of normal wall motion in 16 patients (73%). All patients evolved deep T-wave inversion (average, 7.8 mm) and QT interval lengthening in the precordial leads. Coronary angiography revealed a significant stenosis in the likely culprit artery (left anterior descending) in only one patient.

CONCLUSION

A reversible cardiac contraction abnormality of the anterior wall and apex of the left ventricle can complicate the clinical course of critically ill patients in the absence of significant coronary artery disease. This phenomenon is associated with striking T-wave inversion and QT interval lengthening. Mechanisms other than myocardial ischemia may lead to the occurrence of reversible regional myocardial contraction abnormalities.

Assessing the cause of T wave inversion in precordial leads with ECG mapping

Inversion of the T wave in precordial leads in patients with angina pectoris is a predictor of coronary disease; however, it may also be seen in normal adults. The aim of this study was to assess the cause of T wave inversion by carrying out precordial electrocardiographic (ECG) mapping in 51 patients, who also underwent echocardiography and coronary angiography. The 37 patients in group A had atypical symptoms. They included 11 patients who showed M pattern mapping, of whom 7 had noncoronary cardiac disease and 4 were normal. In 23 other group A patients, whose mappings were in the N pattern, the angiography was normal. In the remaining three patients of this group, mappings were in the I pattern, with angiography revealing coronary disease in two of them and no disease in the third. The 14 group B patients all had typical angina; mappings were in the I pattern in 8 of the patients and in the N pattern in the remaining 6. Angiography revealed coronary artery disease in all patients with the I pattern mapping, while all those with the N pattern were found to be normal. Sensitivity, specificity, and positive predictive value for detecting normal subjects were all 100% for N pattern mapping; for detecting coronary disease, they were 100%, 90%, and 90% for I pattern mapping, respectively. It is concluded that precordial ECG mapping is an accurate method for the assessment of T wave inversion in precordial leads.