These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Difference between electrical remodelling after pulmonary veins and right atrium appendage pacing.
    Author: Hafid KA, Xin HC, Xi W, Yan ZQ, Bo Y.
    Journal: Europace; 2007 Aug; 9(8):608-12. PubMed ID: 17630393.
    Abstract:
    OBJECTIVE: Pulmonary veins (PVs) are important sources of paroxysmal atrial fibrillation (AF). Rapid atrial pacing changes atrial electrophysiology, and facilitates the induction and maintenance of AF. The purpose of our study was to evaluate the changes in atrial effective refractory period (AERP) proprieties and in ionic currents in PVs myocytes from dogs subjected to rapid atrial pacing in PVs and right atrial appendage (RAA) and to relate these changes to the ability to induce AF. METHODS: Twelve mongrel dogs in normal sinus rhythm were paced from the superior left PVs or RAA at 500 bpm for 4 h. Electrophysiological studies were conducted to determine the changes in AERP, dispersion, and rhythm. Ionic currents were evaluated using patch clamp technique in single PVs myocytes in sham-operated dogs, and the results were compared with those from PVs and RAA pacing groups. RESULTS: The presence of rapid atrial pacing was associated with a marked shortening in AERP in both PVs and RAA pacing group with a marked increase in AERP dispersion in PVs pacing. Both L-type calcium current (I(Ca,L)) and the transient outward current (I(to)) were reduced in both groups with an increased significance in PVs pacing group. The density of I(Ca,L) was decreased significantly from (-6.03 +/- 0.63) pA/pF in the control group to (-3.21 +/- 0.34) pA/pF in the PVs pacing group and (-4.75 +/- 0.41) pA/pF in the RAA pacing group (n = 6, P < 0.05), whereas the density of I(to) was decreased significantly from (8.45 +/- 0.71) pA/pF in the control group to (5.21 +/- 0.763) pA/pF in the PVs pacing group and (6.84 +/- 0.69) pA/pF in the RAA pacing group (n = 6, P < 0.05). CONCLUSION: Our findings provide likely ionic mechanisms of shortened repolarization in induced atrial tachycardia with a decrease in I(Ca,L) and I(to) densities, which is the likely mechanism for a decrease in action potential duration rate adaptation in the canine rapid pacing model more pronounced in the PVs pacing group underlying the crucial role of PVs in initiating AF.
    [Abstract] [Full Text] [Related] [New Search]