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: 3.28). 01/2012; 109(7):981-7. DOI: 10.1016/j.amjcard.2011.11.027
Source: PubMed


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.

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Available from: Karina W Davidson, Oct 04, 2015
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    • "Up to now, an absolute value has not been identified to distinguish the normal and abnormal frontal QRS-T angles. Previous studies that were focused on the predictive role of frontal QRS-T angle in cardiovascular diseases determined the cut-off value at either 100° [10] or 90° [11]. In our study, we preferred the cut-off value for frontal QRS-T angle of 90°. "
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    ABSTRACT: Objectives: With the adoption of novel operative techniques and aggressive care protocols that facilitate earlier extubation and mobilization of patients, postoperative length of stay (LOS) following coronary artery bypass graft surgery (CABG) has declined. However, there is paucity of information regarding preoperative electrocardiographic predictors of LOS following CABG. In this study, we investigated whether frontal QRS-T angle, which is an abnormal repolarization marker in prediction of various cardiovascular events, was an independent correlate of postoperative hospital LOS for off-pump CABG. Furthermore, we evaluated independent predictors of vasopressor agent/intra-aortic balloon pump (IABP) support requirement following off-pump CABG. Methods: In this observational study, 78 patients with stable angina, who were scheduled for elective coronary artery bypass surgery following diagnosis of obstructive coronary artery disease by conventional angiography, were enrolled. Results: Left ventricular ejection fraction (LVEF) was significantly lower and vasopressor agent/IABP support requirement and incidence of sustained atrial or ventricular arrhythmias was higher in patients with wide QRS-T angle (P < 0.05). Postoperative hospital LOS was also longer in this group. From the preoperative characteristics, wide frontal QRS-T angle was found to be an independent correlate of postoperative hospital LOS (B ± SD: 11.97 ± 0.62, P ≤ 0.01). Wide frontal QRS-T angle was also found to be an independent predictor of vasopressor agent/IABP support requirement postoperatively (OR: 7.87, P ≤ 0.01). Conclusions: Prediction of the hospital LOS and patient outcome following CABG is of great importance. Being easily obtainable via standard 12-lead electrocardiogram and its low cost may make frontal QRS-T angle a beneficial marker for reducing both patient-based morbidity and economic burden.
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    ABSTRACT: Background A widened electrocardiographic spatial QRS-T angle has been shown to be predictive of cardiovascular disease in HIV-infected individuals. However, determinants and risk factors of developing widened QRS-T angle over time in this population remain unknown. Methods and Results Spatial QRS-T angle was automatically measured from standard electrocardiogram of 1444 HIV-infected individuals without baseline widened spatial QRS-T angle from the Strategies for Management of Antiretroviral Therapy [SMART], a clinical trial comparing two antiretroviral treatment strategies [Drug Conservation (DC) vs. Viral Suppression (VS)]. Conditional logistic regression analysis was used to examine the association between baseline characteristics and incident widened spatial QRS-T angle (a new angle > 93 degrees in males and > 74 degrees in females). During 2544 person-years of follow-up, 199 participants developed widened angle at a rate of 7.8 per 100 person-years. In unadjusted models, female sex, black race (vs. white), DC treatment strategy, current and past smokers (vs. never), history of alcohol abuse, greater body mass index, history of diabetes and higher levels of hs-C-reactive protein were associated with incident widened spatial QRS-T angle. When these variables entered together in the same model with adjustment for demographics and treatment strategy, DC treatment strategy [OR (95% CI): 1.50 (1.09, 2.07)], female gender [1.69 (1.17, 2.45)], current and past smoking (vs. never) [2.49 (1.63, 3.81) and 1.93 (1.21, 3.09), respectively], and diabetes [2.28 (1.33, 3.91)] predicted incident widened spatial QRS-T angle. Conclusions Drug conservation treatment strategy, female gender, smoking, and diabetes are independently predictive of incident widened spatial QRS-T angle in HIV-infected individuals.
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