Electrophysiologic effects of variations in resting tension on canine cardiac tissue

R. Sanders, R. J. Myerburg, K. Nilsson

Research output: Contribution to journalArticle

Abstract

Stretching cardiac tissue may cause deterioration of electrophysiologic properties. To quantitate changes, false tendons (FT) and thin papillary muscles or ventricular trabeculae (VM) were isolated in tissue bath (36°C), and resting length (L) was progressively increased. Resting tension (RT), measured after stress relaxation and corrected for cross sectional area, was plotted against changes in L to determine the L-RT relationships. At each increment of L, the tissue was stimulated at 60/min., and transmembrane action potentials (TMP) analyzed. Data averaged from 30 FTs and 24 VMs demonstrated that FTs were more compliant, requiring a greater increase in L to reach a given RT than did VMs. For both VM and FT, RTs less than 2 gm/mm2 had no influence on TMPs, independent of the L increase. When RT was raised to 2 to 4 gm/mm2, electrical properties changed in most preparations, but reversed within 60 min. At RTs between 4 and 25 gm/mm2, electrical changes became irreversible. RT as an independent variable was the major determinant influencing electrical changes. Thus, the difference in compliance between canine FT and VM results in FTs having a greater resistance to the adverse electrical effects of a measured amount of stretch.

Original languageEnglish (US)
Pages (from-to)No. 974
JournalFederation Proceedings
Volume34
Issue number3
StatePublished - Jan 1 1975
Externally publishedYes

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ASJC Scopus subject areas

  • Medicine(all)

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