| QT dynamics early after exercise as a predictor of mortality. | |
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MedLine Citation:
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PMID: 20478405 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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BACKGROUND: Exercise and QT dynamics during ambulatory monitoring impact mortality in a variety of populations. Heart rate recovery (HRR) after exercise is a known strong predictor of mortality. OBJECTIVE: This study assessed the independent prognostic significance of the QT response to changing heart rate (QT dynamics) during recovery from exercise. METHODS: The cohort included patients referred for treadmill exercise stress testing over a 5-year period. Patients had to have at least 4 electrocardiographic tracings within 5 minutes of peak exercise. One had to be recorded 60 seconds into recovery to calculate the HRR. Linear regression of the QT-RR relation during recovery was used to predict the QT interval at cycle lengths of 500 and 600 ms (QT-500 and QT-600). Only studies with an R(2) > or = 0.9 (72%) were retained. Optimal binary cut points were chosen. All-cause mortality was determined from either the Social Security Death Index or hospital records. RESULTS: A total of 2,994 patients met inclusion criteria; 228 (7.6%) died during an average follow-up of 7.6 +/- 1.9 years. Abnormal QT-500 (>316 ms) was the strongest univariate QT dynamics predictor in a Cox proportional hazards model (hazard ratio = 2.13, P <.001). It remained an independent predictor of mortality after adjustment for age, exercise capacity, medications, single photon emission computed tomography defects, and abnormal (<12 beats/min) HRR (hazard ratio = 1.46, P = .014). CONCLUSION: An abnormal predicted QT interval at 500 ms (120 beats/min) during recovery from exercise independently predicts all-cause mortality. Because QT dynamics in recovery incorporate information on both repolarization and autonomic responsiveness, its role in risk prediction for sudden cardiac death should be further explored. |
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Authors:
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Nils P Johnson; Thomas A Holly; Jeffrey J Goldberger |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural Date: 2010-05-15 |
Journal Detail:
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Title: Heart rhythm : the official journal of the Heart Rhythm Society Volume: 7 ISSN: 1556-3871 ISO Abbreviation: Heart Rhythm Publication Date: 2010 Aug |
Date Detail:
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Created Date: 2010-07-26 Completed Date: 2010-12-15 Revised Date: 2011-09-26 |
Medline Journal Info:
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Nlm Unique ID: 101200317 Medline TA: Heart Rhythm Country: United States |
Other Details:
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Languages: eng Pagination: 1077-84 Citation Subset: IM |
Copyright Information:
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Copyright 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved. |
Affiliation:
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Division of Cardiology, Department of Medicine, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adaptation, Physiological Aged Death, Sudden, Cardiac* / etiology Electrocardiography* Exercise Test* Exercise Tolerance / physiology* Female Heart Rate* Humans Kaplan-Meier Estimate Male Middle Aged Predictive Value of Tests Risk Factors Stress, Physiological |
| Grant Support | |
ID/Acronym/Agency:
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1 RO1 HL 70179-01A2/HL/NHLBI NIH HHS; R01 HL070179-04/HL/NHLBI NIH HHS |
| Comments/Corrections | |
Erratum In:
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Heart Rhythm. 2010 Nov;7(11):1724 |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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