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: Downward gradient in action potential duration along conduction path in and around the sinoatrial node.
    Author: Boyett MR, Honjo H, Yamamoto M, Nikmaram MR, Niwa R, Kodama I.
    Journal: Am J Physiol; 1999 Feb; 276(2):H686-98. PubMed ID: 9950872.
    Abstract:
    Regional differences in electrical activity in rabbit sinoatrial node have been investigated by recording action potentials throughout the intact node or from small balls of tissue from different regions. In the intact node, action potential duration was greatest at or close to the leading pacemaker and declined markedly in all directions from it, e.g., by 74 +/- 4% (mean +/- SE, n = 4) to the crista terminalis. Similar data were obtained from the small balls. The gradient is down the conduction pathway and will help prevent reentry. In the intact node, a zone of inexcitable tissue with small depolarizations of <25 mV or stable resting potentials was discovered in the inferior part of the node, and this will again help prevent reentry. The intrinsic pacemaker activity of the small balls was slower in tissue from more inferior (as well as more central) parts of the node [e.g., cycle length increased from 339 +/- 13 ms (n = 6) to 483 +/- 13 ms (n = 6) in transitional tissue from more superior and inferior sites], and this may help explain pacemaker shift.
    [Abstract] [Full Text] [Related] [New Search]