Document Detail

Acute effects of caffeine ingestion on signal-averaged electrocardiograms.
MedLine Citation:
PMID:  9778067     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: Although moderate caffeine ingestion has not been shown to be arrhythmogenic, caffeine toxicity can cause severe cardiac arrhythmias, including atrial fibrillation and ventricular tachycardia. Atrial fibrillation and ventricular tachycardia have been associated with prolongation of P-wave and QRS complex durations on signal-averaged electrocardiograms. This study investigated acute effects of caffeine ingestion on signal-averaged P-wave and QRS complexes. METHODS AND RESULTS: Signal-averaged electrocardiograms were obtained from 12 normal subjects (6 men, 6 women; ages 21 to 26 years) before and after ingestion of caffeine (5 mg/kg body weight) or placebo in a randomized, double-blind, crossover fashion. Electrocardiograms for signal averaging were recorded from electrodes left in a constant location. After bandpass filtering (30 to 300 Hz) and amplification, signals were sampled over 7.2 minutes at 2000 Hz. Signal-averaged P-wave and QRS complex durations did not significantly change after placebo ingestion. After caffeine ingestion QRS duration prolonged in 9 of 11 subjects at 90 minutes (mean +/- SEM = 0.8+/-0.3 ms, P< .02) and in 8 of 9 after 3 hours (1.1+/-0.2 ms, P< .001). No significant change in P-wave duration or heart rate was found after caffeine ingestion at any test interval. Average caffeine level in saliva 90 minutes after ingestion was 6.6+/-1.6 (SD) microg/dL. CONCLUSIONS: Although probably not arrhythmogenic in normal subjects, moderate caffeine ingestion does produce a small but statistically significant prolongation of signal-averaged QRS complexes. Further prolongation caused by excessive caffeine intake may be a factor in the genesis of arrhythmias associated with caffeine toxicity.
R L Donnerstein; D Zhu; R Samson; A M Bender; S J Goldberg
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Publication Detail:
Type:  Clinical Trial; Journal Article; Randomized Controlled Trial    
Journal Detail:
Title:  American heart journal     Volume:  136     ISSN:  0002-8703     ISO Abbreviation:  Am. Heart J.     Publication Date:  1998 Oct 
Date Detail:
Created Date:  1998-11-04     Completed Date:  1998-11-04     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0370465     Medline TA:  Am Heart J     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  643-6     Citation Subset:  AIM; IM    
Department of Pediatrics, Steele Memorial Children's Research Center, The University of Arizona College of Medicine, Tucson, USA.
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MeSH Terms
Arrhythmias, Cardiac / chemically induced*
Caffeine / adverse effects*
Central Nervous System Stimulants / adverse effects*
Cross-Over Studies
Double-Blind Method
Electrocardiography / drug effects*
Reference Values
Signal Processing, Computer-Assisted
Reg. No./Substance:
0/Central Nervous System Stimulants; 58-08-2/Caffeine
Comment In:
Am Heart J. 1998 Oct;136(4 Pt 1):574-5   [PMID:  9778058 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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