Linked Life Data

1873867

Source:http://linkedlifedata.com/resource/pubmed/id/1873867

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
1991-9-26
pubmed:abstractText
Orthogonal sequential shock can defibrillate the heart with greater efficacy compared with single shock defibrillation. In this study we tested the hypothesis that cardiac cells have a preferred orientation in their response to excitatory extracellular electric fields, so that orthogonal shocks may stimulate distinct populations of cells. A micropaddle electrode system was used to deliver rectangular pulses for extracellular field stimulation of individual heart cells. We found that single frog and guinea pig ventricular myocytes are excitable with rectangular pulse field stimulation over a wide range of pulse durations, ranging from 10 msec to as little as 20 microseconds. The excitation field strength varies inversely with pulse duration as described by the Weiss-Lapicque equation, although the frog myocytes show a significant "notch" at pulse durations of approximately 1-2 msec, and the guinea pig myocytes are more excitable than predicted for pulse durations of less than 0.2 msec. Every myocyte tested was more excitable when the long axis of the cell was oriented parallel to the stimulating field than when perpendicular to the field. For 2-msec pulses, the difference in field strength was a factor of 5.8 +/- 2.0 (n = 30) for frog and 2.6 +/- 0.5 (n = 23) for guinea pig myocytes. Complete excitation strength-duration curves were obtained in seven frog and 14 guinea pig cells for both parallel and perpendicular cell orientations.(ABSTRACT TRUNCATED AT 250 WORDS)
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0009-7330
pubmed:author
pubmed:issnType
Print
pubmed:volume
69
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
722-30
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1991
pubmed:articleTitle
Influence of electrical axis of stimulation on excitation of cardiac muscle cells.
pubmed:affiliation
Department of Biomedical Engineering, Johns Hopkins University, Baltimore, MD 21205.
pubmed:publicationType
Journal Article, Comparative Study, In Vitro, Research Support, U.S. Gov't, Non-P.H.S., Research Support, Non-U.S. Gov't