Document Detail

Distinguishing properties of cells from the myocardial sleeves of the pulmonary veins: a comparison of normal and abnormal pacemakers.
MedLine Citation:
PMID:  19808392     Owner:  NLM     Status:  MEDLINE    
BACKGROUND: A common source of arrhythmogenic spontaneous activity instigating atrial fibrillation is the myocardial tissue, or sleeves, at the base of the pulmonary veins. This study compared the properties of cells from the myocardial sleeves of the pulmonary veins (PV(m)) with cells from the normal cardiac pacemaker (the sinoatrial node) and regions of the atria. Our objective was to identify key features of these cells that predispose them to becoming the focus of cardiac arrhythmias. METHODS AND RESULTS: Single cells were isolated from samples of rabbit PV(m), central and peripheral sinoatrial node, crista terminalis, and left and right atria. Detailed morphology of cells was assessed and intracellular calcium concentrations measured with the use of Fluo-3. Cells from the PV(m) were smaller than atrial cells and showed large elevations in diastolic calcium during activation at physiological rates, a feature the PV(m) cells shared with cells from the sinoatrial node. Unstimulated spontaneous activity was observed in a minority of cells from the PV(m), but numerous cells from this region showed spontaneous activity for a brief period immediately subsequent to stimulation at physiological rates. This was not observed in atrial cells. Assessment of calcium removal pathways showed sarcolemmal calcium extrusion in cells from the PV(m) to have a high reliance on "slow" extrusion pathways to maintain intracellular calcium homeostasis because of a low expression of sodium-calcium exchanger. CONCLUSIONS: We conclude that cells from the PV(m) share some features with cells from the sinoatrial node but also have distinctly unique features that predispose them to the development of spontaneous activity.
Sandra A Jones; Mitsuru Yamamoto; James O Tellez; Rudi Billeter; Mark R Boyett; Haruo Honjo; Matthew K Lancaster
Publication Detail:
Type:  Comparative Study; In Vitro; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Circulation. Arrhythmia and electrophysiology     Volume:  1     ISSN:  1941-3084     ISO Abbreviation:  Circ Arrhythm Electrophysiol     Publication Date:  2008 Apr 
Date Detail:
Created Date:  2009-10-07     Completed Date:  2009-10-26     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101474365     Medline TA:  Circ Arrhythm Electrophysiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  39-48     Citation Subset:  IM    
Biomedical Sciences, University of Hull, Kingston-Upon-Hull, UK.
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MeSH Terms
Action Potentials
Arrhythmias, Cardiac / metabolism*,  physiopathology
Biological Clocks* / drug effects
Caffeine / pharmacology
Calcium Signaling* / drug effects
Cardiac Pacing, Artificial
Cell Shape
Heart Atria / metabolism
Myocytes, Cardiac / drug effects,  metabolism*
Pulmonary Veins / drug effects,  metabolism*,  physiopathology
RNA, Messenger / metabolism
Ryanodine / pharmacology
Ryanodine Receptor Calcium Release Channel / genetics,  metabolism
Sarcolemma / metabolism
Sarcoplasmic Reticulum / metabolism
Sarcoplasmic Reticulum Calcium-Transporting ATPases / genetics,  metabolism
Sinoatrial Node / drug effects,  metabolism*,  physiopathology
Sodium-Calcium Exchanger / genetics,  metabolism
Grant Support
//British Heart Foundation
Reg. No./Substance:
0/RNA, Messenger; 0/Ryanodine Receptor Calcium Release Channel; 0/Sodium-Calcium Exchanger; 0/sodium-calcium exchanger 1; 15662-33-6/Ryanodine; 58-08-2/Caffeine; EC Reticulum Calcium-Transporting ATPases

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