Are interatrial band myocytes maximally hypertrophied in normal canine hearts?

Paul C. Dolber, Robert P. Bauman, Judith C. Rembert, Joseph C. Greenfield

Research output: Contribution to journalArticle

Abstract

In canine right atrial hypertrophy, the cross-sectional area (A(xs)) of right atrial myocytes increases, whereas the A(xs) of the broader interatrial band myocytes does not. In the current study, myocyte reconstructions showed that right atrial myocyte length increased in proportion to A(xs) in right atrial hypertrophy. On the other hand, mean interatrial band myocyte length in both normal and right atrial hypertrophy dogs was roughly inversely proportional to mean A(xs), as expected if interatrial band myocyte volume was constant. Plotting mean A(xs) vs. myocyte length for individual interatrial band myocytes revealed a distribution whose border defined a maximal volume curve; many myocytes were well beneath that curve. Mononuclear myocytes (generally diploid) were limited by a 65,000-μm3 curve, which many binuclear myocytes (generally tetraploid) surpassed; myocyte ploidy thus constrained myocyte volume. However, because many mononuclear and binuclear myocytes had lower volumes, their failure to hypertrophy cannot be attributed to attainment of the maximal volume possible for their ploidy.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume275
Issue number4 44-4
StatePublished - 1998
Externally publishedYes

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Keywords

  • Atrium
  • Cardiac muscle
  • Hypertrophy
  • Myocyte size
  • Ploidy

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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