Spatial heterogeneity of calcium transient alternans during the early phase of myocardial ischemia in the blood-perfused rabbit heart

You-Wen Qian, William T. Clusin, Shien Fong Lin, Jennifer Han, Ruey J. Sung

Research output: Contribution to journalArticle

91 Citations (Scopus)

Abstract

Background - Optical mapping of cytosolic calcium transients in intact mammalian hearts is now possible using long-wavelength [Ca2+]i indicators. We propose that beat-to-beat [Ca2+]i transient alternans during ischemia may lead to spatial and temporal heterogeneity of calcium-activated membrane currents. Methods and Results - To test this hypothesis, isolated rabbit hearts were loaded with the fluorescent [Ca2+]i indicator, rhod-2 AM, and imaged at 300 frames/sec during blood-perfused ischemic trials. High-quality [Ca2+]i transients were recorded in each of 8 hearts. [Ca2+]i transient alternans was never present in control records but occurred in each of the hearts during ischemia, with onset after 2 to 4 minutes. Alternans was confined to circumscribed regions of the heart surface 5 to 15 mm across. Multiple regions of alternans were found in most hearts, and regions that were out of phase with one another were found in 6 hearts. Quantitative maps of alternans were constructed by calculating an alternans ratio. This ratio behaved as a continuous variable that reached a maximum value in the center of the regions with alternans. Conclusions - These results demonstrate marked spatial heterogeneity of the [Ca2+]i transient during the early phase of ischemia, which could produce electrical instability and arrhythmias in large mammalian hearts.

Original languageEnglish (US)
Pages (from-to)2082-2087
Number of pages6
JournalCirculation
Volume104
Issue number17
StatePublished - Oct 23 2001
Externally publishedYes

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Myocardial Ischemia
Rabbits
Calcium
Ischemia
Cardiac Arrhythmias
Membranes

Keywords

  • Arrhythmias
  • Calcium
  • Fluorescence
  • Ischemia
  • Myocardium

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

Cite this

Spatial heterogeneity of calcium transient alternans during the early phase of myocardial ischemia in the blood-perfused rabbit heart. / Qian, You-Wen; Clusin, William T.; Lin, Shien Fong; Han, Jennifer; Sung, Ruey J.

In: Circulation, Vol. 104, No. 17, 23.10.2001, p. 2082-2087.

Research output: Contribution to journalArticle

Qian, You-Wen ; Clusin, William T. ; Lin, Shien Fong ; Han, Jennifer ; Sung, Ruey J. / Spatial heterogeneity of calcium transient alternans during the early phase of myocardial ischemia in the blood-perfused rabbit heart. In: Circulation. 2001 ; Vol. 104, No. 17. pp. 2082-2087.
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AU - Sung, Ruey J.

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N2 - Background - Optical mapping of cytosolic calcium transients in intact mammalian hearts is now possible using long-wavelength [Ca2+]i indicators. We propose that beat-to-beat [Ca2+]i transient alternans during ischemia may lead to spatial and temporal heterogeneity of calcium-activated membrane currents. Methods and Results - To test this hypothesis, isolated rabbit hearts were loaded with the fluorescent [Ca2+]i indicator, rhod-2 AM, and imaged at 300 frames/sec during blood-perfused ischemic trials. High-quality [Ca2+]i transients were recorded in each of 8 hearts. [Ca2+]i transient alternans was never present in control records but occurred in each of the hearts during ischemia, with onset after 2 to 4 minutes. Alternans was confined to circumscribed regions of the heart surface 5 to 15 mm across. Multiple regions of alternans were found in most hearts, and regions that were out of phase with one another were found in 6 hearts. Quantitative maps of alternans were constructed by calculating an alternans ratio. This ratio behaved as a continuous variable that reached a maximum value in the center of the regions with alternans. Conclusions - These results demonstrate marked spatial heterogeneity of the [Ca2+]i transient during the early phase of ischemia, which could produce electrical instability and arrhythmias in large mammalian hearts.

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