| Origins of heart rate variability: relationship of heart rate burst morphology to work duration and load. | |
| | |
MedLine Citation:
|
PMID: 10516187 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
We are developing a lexicon of specific heart period changes, or lexons, that recur frequently and whose physiological meaning can be read into ambulatory electrocardiogram (ECG). The transient, reversible "burst" of tachycardia induced by exercise initiation can also be seen on ambulatory ECG. We hypothesized that burst morphology depended on the work that preceded it and on baroreceptor activation. Ten subjects with mean age 38 yr (range 17-69 yr) underwent two protocols of semisupine cycling in which load and duration were varied. Burst duration increased with longer cycling times (median values of 18.0, 25.5, and 23.7 s with 1, 3, and 5 s of cycling, respectively; P = 0.033). Burst shape as assessed by heart period exponential decay constant and burst magnitude did not change. To assess the impact of workload, subjects cycled for 5 s at loads of 0, 25, 50, and 75 W. No significant differences were seen in burst duration, burst magnitude, or burst shape. Tachycardia preceded hypotension by 4.6 +/- 2.2 s, which is inconsistent with baroreceptor involvement in the onset of burst tachycardia. Because burst morphology is a nearly quantal response to the initiation of exercise, the presence of a burst on an ambulatory ECG implies the onset of exercise. |
| | |
Authors:
|
D Roach; R Haennel; M L Koshman; R Sheldon |
Related Documents
:
|
6517987 - Pathophysiology and treatment of septic shock. 7641247 - The effects of aspirin on the cnv in healthy individuals. 17015067 - Biopotential fiber sensor. 12458067 - Defibrillation with a minimally invasive direct cardiac massage device. 14768777 - Short-term effects of two integrated, non-pharmacological body weight reduction program... 2266757 - Physiological adjustments of facial cooling during exercise. |
Publication Detail:
|
Type: Clinical Trial; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't |
Journal Detail:
|
Title: The American journal of physiology Volume: 277 ISSN: 0002-9513 ISO Abbreviation: Am. J. Physiol. Publication Date: 1999 Oct |
Date Detail:
|
Created Date: 1999-11-17 Completed Date: 1999-11-17 Revised Date: 2008-11-21 |
Medline Journal Info:
|
Nlm Unique ID: 0370511 Medline TA: Am J Physiol Country: UNITED STATES |
Other Details:
|
Languages: eng Pagination: H1491-7 Citation Subset: IM; S |
Affiliation:
|
Cardiovascular Research Group, University of Calgary, Calgary, Alberta, Canada T2N 4N1. |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Adolescent Adult Aged Bicycling Blood Pressure / physiology Electrocardiography, Ambulatory Female Heart Rate / physiology* Humans Male Middle Aged Physical Exertion / physiology* Supine Position Time Factors |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Miconazole represses CO(2)-induced pial arteriolar dilation only under selected circumstances.
Next Document: Depolarization-mediated inhibition of Ca(2+) entry in endothelial cells.