Article

Relations between QRS|T angle, cardiac risk factors, and mortality in the third National Health and Nutrition Examination Survey (NHANES III).

Department of Medicine, Columbia University Medical Center, New York, New York, USA.
The American journal of cardiology (Impact Factor: 3.43). 01/2012; 109(7):981-7. DOI: 10.1016/j.amjcard.2011.11.027
Source: PubMed

ABSTRACT On the surface electrocardiogram, an abnormally wide QRS|T angle reflects changes in the regional action potential duration profiles and in the direction of the repolarization sequence, which is thought to increase the risk of ventricular arrhythmia. We investigated the relation between an abnormal QRS|T angle and mortality in a nationally representative sample of subjects without clinically evident heart disease. We studied 7,052 participants ≥40 years old in the third National Health and Nutrition Examination Survey with 12-lead electrocardiograms. Those with self-reported or electrocardiographic evidence of a previous myocardial infarction, QRS duration of ≥120 ms, or history of heart failure were excluded. Borderline and abnormal spatial QRS|T angles were defined according to gender-specific 75th and 95th percentiles of frequency distributions. All-cause (1,093 women and 1,191 men) and cardiovascular (462 women and 455 men) mortality during the 14-year period was assessed through linkage with the National Death Index. On multivariate analyses, an abnormal spatial QRS|T angle was associated with an increased hazard ratio (HR) for cardiovascular mortality in women (HR 1.82, 95% confidence interval 1.05 to 3.14) and men (HR 2.21, 95% confidence interval 1.32 to 3.68). Also, the multivariate adjusted HR for all-cause mortality associated with an abnormal QRS|T angle was 1.30 (95% confidence interval 0.95 to 1.78) for women and 1.87 (95% confidence interval 1.29 to 2.7) for men. A borderline QRS|T angle was not associated with an increased risk of all-cause or cardiovascular mortality. In conclusion, an abnormal QRS|T angle, as measured on a 12-lead electrocardiogram, was associated with an increased risk of cardiovascular and all-cause mortality in this population-based sample without known heart disease.

0 Followers
 · 
107 Views
  • [Show abstract] [Hide abstract]
    ABSTRACT: The spatial QRS/T angle (QRS/T) has been identified as a strong and independent predictor of adverse cardiac events. QRS/T can be determined from the electrocardiogram (ECG) by matrix transformation methods or formula which uses a combination of net QRS and T-wave amplitudes (QRS/Tsimple). Amplitudes can be measured automatically by using dedicated software (QRS/Tauto) or can be manually measured on a computer screen (QRS/Tmanual). This latter method allows analysis of QRS/T, when digital ECGs are not available. The aim of the study was to determine the agreement in the measurements between automatically derived QRS and T amplitudes and manually measured on the computer screen amplitudes. The relative error of the QRS/T between the two methods was estimated in 73 patients. In the case of QRS/Tmanual the inter-observer as well as intra-observer variability was estimated. The relative error between QRS/Tauto vs. QRS/Tmanual was 3.51%. Inter-observer and intra-observer variability of the QRS/Tmanual was 1.19% and 1.18% respectively. Manual measurement of the QRS/T is reliable, however, the predictive value of this parameter should be tested in clinical trials, before QRS/Tmanual can be considered a useful tool in clinical practice or retrospective studies.
    Central European Journal of Medicine 12/2014; 9(6). DOI:10.2478/s11536-013-0342-7 · 0.21 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The aim of this study was to test the hypothesis that depression and anxiety are associated with electrocardiographic (ECG) repolarization abnormalities in the Multi-Ethnic Study of Atherosclerosis (MESA), a cohort free of symptomatic cardiovascular disease. Depressive symptoms were assessed by using the Center for Epidemiologic Studies Depression Scale and trait anxiety symptoms by using the Spielberger State-Trait Anxiety Inventory; both were categorized according to uppermost quartile. T-wave inversions in ECG leads other than V1 to V3 were obtained from electrocardiograms obtained at rest during the baseline examination. Participants with major intraventricular conduction abnormalities and those taking antiarrhythmics, antidepressants, and/or antipsychotics were excluded. Logistic regression models were estimated with multivariable adjustment for traditional cardiovascular disease risk factors. Among 5,906 participants, elevated depressive symptoms were associated with increased odds of T-wave inversion after multivariable adjustment (odds ratio 2.02, 95% confidence interval 1.33 to 3.06, p = 0.001), whereas greater trait anxiety was associated with reduced odds of T-wave inversion (odds ratio 0.47, 95% confidence interval 0.29 to 0.77, p = 0.003). The divergent associations of depressive symptoms and trait anxiety with ECG T-wave inversions were similar in men and women, and these associations were present across the racial and ethnic subgroups (non-Hispanic white, African-American, Hispanic, and Chinese). In conclusion, symptoms of depression and anxiety were independently yet oppositely associated with ECG T-wave inversions. Negative emotions may have a differential impact on cardiovascular mortality through unique relations with cardiac repolarization. Copyright © 2014 Elsevier Inc. All rights reserved.
    The American Journal of Cardiology 09/2014; 114(12):1917-1922. DOI:10.1016/j.amjcard.2014.09.034 · 3.43 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Background: Congenital long QT syndrome type 2 (abnormal hERG potassium channel) patients can develop flat, asymmetric, and notched T waves. Similar observations have been made with a limited number of hERG-blocking drugs. However, it is not known how additional calcium or late sodium block, that can decrease torsade risk, affects T wave morphology. Methods and Results: Twenty-two healthy subjects received a single dose of a pure hERG blocker (dofetilide) and 3 drugs that also block calcium or sodium (quinidine, ranolazine, and verapamil) as part of a 5-period, placebo-controlled cross-over trial. At pre-dose and 15 time-points postdose, ECGs and plasma drug concentration were assessed. Patch clamp experiments were performed to assess block of hERG, calcium (L-type) and late sodium currents for each drug. Pure hERG block (dofetilide) and strong hERG block with lesser calcium and late sodium block (quinidine) caused substantial T wave morphology changes (P<0.001). Strong late sodium current and hERG block (ranolazine) still caused T wave morphology changes (P<0.01). Strong calcium and hERG block (verapamil) did not cause T wave morphology changes. At equivalent QTc prolongation, multichannel blockers (quinidine and ranolazine) caused equal or greater T wave morphology changes compared with pure hERG block (dofetilide). Conclusions: T wave morphology changes are directly related to amount of hERG block; however, with quinidine and ranolazine, multichannel block did not prevent T wave morphology changes. A combined approach of assessing multiple ion channels, along with ECG intervals and T wave morphology may provide the greatest insight into drug-ion channel interactions and torsade de pointes risk.
    Journal of the American Heart Association 04/2015; 4(4):e001615. DOI:10.1161/JAHA.114.001615 · 2.88 Impact Factor

Full-text (2 Sources)

Download
29 Downloads
Available from
May 21, 2014