High-energy defibrillation impairs myocyte contractility and intracellular calcium dynamics.

Giuseppe Ristagno, Tong Wang, Wanchun Tang, Shijie Sun, Carlos Castillo, Max Harry Weil

Research output: Contribution to journalArticle

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Abstract

OBJECTIVES: We examined the effects of energy delivered with electrical defibrillation on myocyte contractility and intracellular Ca2+ dynamics. We hypothesized that increasing the defibrillation energy would produce correspondent reduction in myocyte contractility and intracellular Ca2+ dynamics. DESIGN: Randomized prospective study. SETTING: University-affiliated research laboratory. SUBJECTS: Ventricular myocytes from male Sprague-Dawley rat hearts. MATERIALS AND METHODS: Ventricular cardiomyocytes loaded with Fura-2/AM were placed in a chamber mounted on an inverted microscope and superfused with a buffer solution at 37 degrees C. The cells were field stimulated to contract and mechanical properties were assessed using a video-based edge-detection system. Intracellular Ca2+ dynamics were evaluated with a dual-excitation fluorescence photomultiplier system. Myocytes were then randomized to receive 1) a single 0.5-J biphasic shock; 2) a single 1-J biphasic shock; 3) a single 2-J biphasic shock; and 4) a control group without shock. After the shock, myocytes were paced for an additional 4 mins. RESULTS: A single 0.5-J shock did not have effects on contractility and intracellular Ca2+ dynamics. Higher energy shocks, i.e., 1- or 2-J shocks, significantly impaired contractility and intracellular Ca2+ dynamics. The adverse effects were greater after a 2-J shock compared with a 1-J shock. CONCLUSIONS: Higher defibrillation energy significantly impairs ventricular contractility at the myocyte level. Reductions in cardiomyocyte shortening and intracellular Ca2+ dynamics abnormalities were greater when higher energy shock was used.

Original languageEnglish
JournalCritical Care Medicine
Volume36
Issue number11 Suppl
Publication statusPublished - Nov 2008

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Muscle Cells
Shock
Calcium
Cardiac Myocytes
Sprague Dawley Rats
Buffers
Fluorescence
Prospective Studies
Control Groups

ASJC Scopus subject areas

  • Critical Care and Intensive Care Medicine

Cite this

Ristagno, G., Wang, T., Tang, W., Sun, S., Castillo, C., & Weil, M. H. (2008). High-energy defibrillation impairs myocyte contractility and intracellular calcium dynamics. Critical Care Medicine, 36(11 Suppl).

High-energy defibrillation impairs myocyte contractility and intracellular calcium dynamics. / Ristagno, Giuseppe; Wang, Tong; Tang, Wanchun; Sun, Shijie; Castillo, Carlos; Weil, Max Harry.

In: Critical Care Medicine, Vol. 36, No. 11 Suppl, 11.2008.

Research output: Contribution to journalArticle

Ristagno, G, Wang, T, Tang, W, Sun, S, Castillo, C & Weil, MH 2008, 'High-energy defibrillation impairs myocyte contractility and intracellular calcium dynamics.', Critical Care Medicine, vol. 36, no. 11 Suppl.
Ristagno, Giuseppe ; Wang, Tong ; Tang, Wanchun ; Sun, Shijie ; Castillo, Carlos ; Weil, Max Harry. / High-energy defibrillation impairs myocyte contractility and intracellular calcium dynamics. In: Critical Care Medicine. 2008 ; Vol. 36, No. 11 Suppl.
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