Analysis of 12-Lead T-Wave Morphology for Risk Stratification After Myocardial Infarction

Zabel, Markus; Açar, Burak; Klingenheben, Thomas; Franz, Michael R.; Hohnloser, Stefan H.; Malik, Marek

doi:10.1161/01.cir.102.11.1252

Cited by 217 publications

(207 citation statements)

References 46 publications

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“…Although many authors have repeatedly pointed out that ventricular gradient is an index of repolarization heterogeneity, only one prospective study has tested its prognostic value. 13 Our study confirmed the results reported by Zabel et al, 15 obtained with different dichotomy value (TCRT < 0.158). When we applied this cut-off value to our data, TCRT was again the strongest independent predictor of cardiac death (RR 4.5, 95% CI 1.3-15.3, p = 0.014), while the 657 Abbreviations as in Table II.…”

Section: Discussionsupporting

confidence: 91%

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Prognostic value of heterogeneity of ventricular repolarization in survivors of acute myocardial infarction

Batchvarov¹,

Hnatkova²,

Poloniecki³

et al. 2004

Clinical Cardiology

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SummaryBackground: The expansion of indications for implantation of cardioverter-defibrillators (ICD) has enhanced the need for risk stratification of patients post myocardial infarction (MI), while the improved treatment of acute MI has decreased mortality and diminished the prognostic power of traditional risk variables.Hypothesis: Increased heterogeneity of ventricular repolarization quantified by TCRT (total cosine R-to-T, angular difference between spatial QRS and T loops, decreased with increase in repolarization heterogeneity) is an independent predictor of mortality in patients post MI.Methods: Left ventricular ejection fraction (EF), QRS duration on signal-averaged ECG, number of ventricular ectopic beats (VE)/h, heart rate variability (HRV) triangular index, heart rate turbulence slope on 24-h Holter recording, and TCRT were analyzed in 334 survivors of acute MI followed up for 41 ± 20 months.Results: In multivariate analysis, EF < 35% (relative risk [RR] 2.3, 95% confidence interval [CI] 1.1-4.7, p = 0.023), VE > 10/h (RR 2.2, CI 1.0-4.6, p = 0.044), HRV < 20 U (RR 2.2, CI 1.1-4.5, p = 0.032), and TCRT < Ϫ0.896 (RR 4.3, CI 2.2-8.5, p = 0.00001) were independent predictors of cardiac mortality (11%). Independent predictors of arrhythmic mortality (5%) were VE, HRV, and TCRT (RR 5.8, CI 2.1-15.6, p = 0.0004). Cardiac and arrhythmic mortality of patients with both EF < 35% and TCRT < Ϫ0.896 were > 60 and > 30%,

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Section: Discussionsupporting

confidence: 91%

“…Despite these limitations it is reasonable to expect that TCRT would retain (at least partially) its prognostic power in patients post MI treated according to modern standards, as suggested by the study of Zabel et al 15 …”

Section: Limitationsmentioning

confidence: 99%

Prognostic value of heterogeneity of ventricular repolarization in survivors of acute myocardial infarction

Batchvarov¹,

Hnatkova²,

Poloniecki³

et al. 2004

Clinical Cardiology

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“…This index is not sensitive to subjective definition of the end of the T-wave and is therefore a reproducible and reliable index of cardiac repolarisation. This index was recently described to be a powerful predictor of mortality in various populations [12][13][14][15][16]. TCRT values tended to be more abnormal (smaller) in diabetic patients, even when glucose levels were normal and the abnormality became more marked during hypoglycaemia, suggesting that hypoglycaemia further increases the heterogeneity in global repolarisation.…”

Section: Discussionmentioning

confidence: 96%

“…Therefore, novel repolarisation analyses have been developed to evaluate the characteristics of cardiac repolarisation with greater accuracy. New descriptors of T-wave morphology and the spatial QRS-T angle have already been shown to have better prognostic values than QT interval or QT dispersion with regard to cardiac events in several populations [12][13][14][15][16] and increased complexity of ventricular repolarisation measured by principal component analysis of T-wave morphology has been found to distinguish patients with congenital long QT syndrome from unaffected participants [17,18]. Therefore, we decided to study the effects of controlled insulininduced hypoglycaemia on the T-wave loop and the QRS complex loop in type 1 diabetic patients and age-matched non-diabetic control participants.…”

Section: Introductionmentioning

confidence: 99%

Effects of controlled hypoglycaemia on cardiac repolarisation in patients with type 1 diabetes

et al. 2007

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Aims/hypothesis Nocturnal hypoglycaemia may contribute to sudden death in diabetic patients. However, it is not well known why hypoglycaemia makes these patients prone to death. Methods We assessed the effects of controlled hypoglycaemia on cardiac repolarisation using novel electrocardiographic descriptors of T-wave and QRS complex morphology in 16 type 1 diabetic patients and eight healthy counterparts. Several electrocardiographic variables characterising repolarisation were analysed from digitised 12-lead electrocardiograms during a euglycaemic and a hypoglycaemic clamp. Results Hypoglycaemia did not result in significant changes either in the QT interval corrected for heart rate by the nomogram method or in QT dispersion. However, the morphology of the T-wave changed significantly during hypoglycaemia. The T-wave amplitude and area in precordial leads decreased significantly in both groups (p<0.05 to p<0.001). The spatial QRS-T angle (total cosine R to T) (p<0.05) and the height and the width of the T-wave loop (p<0.05 and p<0.01, respectively) were also reduced in the diabetic patients. The changes in the repolarisation parameters did not exhibit any significant association with changes in catecholamine levels or in heart rate variability in either group. Conclusions/interpretation Hypoglycaemia results in distinct alterations in cardiac repolarisation, which may increase the vulnerability to arrhythmic events.

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“…ECG measures of the heterogeneity or complexity of ventricular repolarization have been implicated in the genesis of ventricular arrhythmias and also associated with adverse prognosis (6 -14). A number of surface ECG approaches to analysis of repolarization heterogeneity have been proposed, including QT dispersion (6,9,12), T-wave morphology analyses (9,10,13), and principal component analysis (PCA) of the T-wave vector loop (11,14), a spatial measure of T-wave complexity that avoids many of the theoretical and practical limitations of simple QT dispersion and improves prediction of CV death (11,14). However, these repolarization abnormalities may be strongly correlated with one another (11), and whether they provide independent prognostic information when examined together remains unclear.…”

mentioning

confidence: 99%

Electrocardiographic Repolarization Complexity and Abnormality Predict All-Cause and Cardiovascular Mortality in Diabetes

et al. 2004

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Type 2 diabetes is associated with increased risk of cardiovascular (CV) and all-cause mortality. Although electrocardiographic measures of repolarization abnormality and complexity stratify risk in the general population, their prognostic value in diabetes has not been well characterized. Digital electrocardiogram (ECG) readings were acquired for 994 American Indians with type 2 diabetes. ST segment depression (STD) >50 V and rate-corrected QT interval (QTc) >460 ms were examined as measures of repolarization abnormality. The principal component analysis (PCA) of the ratio of the second to first eigenvalues of the T-wave vector (PCA ratio) (>32.0% in women and >24.6% in men) was examined as a measure of repolarization complexity on the ECG. After a mean follow-up of 4.7 ؎ 1.0 years, there were 56 CV deaths and 155 deaths from all causes. In univariate analyses, STD, QTc, and the PCA ratio predicted CV and all-cause mortality. T he surface electrocardiogram (ECG) remains the most widely used noninvasive method for cardiovascular (CV) risk assessment. Abnormalities of ventricular repolarization on the ECG, such as ST segment depression (STD) and QT interval prolongation, are well-established markers of mortality risk in the general population (1-6). ECG measures of the heterogeneity or complexity of ventricular repolarization have been implicated in the genesis of ventricular arrhythmias and also associated with adverse prognosis (6 -14). A number of surface ECG approaches to analysis of repolarization heterogeneity have been proposed, including QT dispersion (6,9,12), T-wave morphology analyses (9,10,13), and principal component analysis (PCA) of the T-wave vector loop (11,14), a spatial measure of T-wave complexity that avoids many of the theoretical and practical limitations of simple QT dispersion and improves prediction of CV death (11,14). However, these repolarization abnormalities may be strongly correlated with one another (11), and whether they provide independent prognostic information when examined together remains unclear.Diabetes is an established risk factor for CV disease and is associated with an increased risk of both all-cause and CV mortality (15)(16)(17)(18)(19). The increasing prevalence of type 2 diabetes, earlier onset of diabetes, and aging of the population will result in an increasing prevalence of diabetesinduced CV disease (18,19), suggesting that accurate noninvasive identification of diabetic individuals at high risk may play a role in the development of more effective preventive strategies for decreasing diabetes-related CV risks (19). Although increased QT interval and QT dispersion have been implicated as possible ECG predictors of CV and all-cause mortality in several small type 2 diabetic cohorts (20 -22), the prognostic value of the QT interval has not been examined in an unselected type 2 diabetic population, and the prognostic value of STD and the more accurate PCA ratio have not been assessed in diabetes. Therefore, the present study examined the value of repolarization abn...

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Analysis of 12-Lead T-Wave Morphology for Risk Stratification After Myocardial Infarction

Abstract: Computerized T-wave morphology analysis of the 12-lead resting ECG permits independent assessment of post-MI risk and an improved risk stratification when combined with other risk markers.

Cited by 217 publications

References 46 publications

Prognostic value of heterogeneity of ventricular repolarization in survivors of acute myocardial infarction

Prognostic value of heterogeneity of ventricular repolarization in survivors of acute myocardial infarction

Effects of controlled hypoglycaemia on cardiac repolarisation in patients with type 1 diabetes

Electrocardiographic Repolarization Complexity and Abnormality Predict All-Cause and Cardiovascular Mortality in Diabetes

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