Regional cooling facilitates termination of spiral-wave reentry through unpinning of rotors in rabbit hearts

Masatoshi Yamazaki, Haruo Honjo, Takashi Ashihara, Masahide Harada, Ichiro Sakuma, Kazuo Nakazawa, Natalia Trayanova, Minoru Horie, Jérme Kalifa, José Jalife, Kaichiro Kamiya, Itsuo Kodama

Research output: Contribution to journalArticle

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Abstract

Moderate global cooling of myocardial tissue was shown to destabilize 2-dimensional (2-D) reentry and facilitate its termination. This study sought to test the hypothesis that regional cooling destabilizes rotors and facilitates termination of spontaneous and DC shock-induced subepicardial reentry in isolated, endocardially ablated rabbit hearts. Fluorescent action potential signals were recorded from 2-D subepicardial ventricular myocardium of Langendorff-perfused rabbit hearts. Regional cooling (by 5.9°C ± 1.3°C) was applied to the left ventricular anterior wall using a transparent cooling device (10 mm in diameter). Regional cooling during constant stimulation (2.5 Hz) prolonged the action potential duration (by 36% ± 9%) and slightly reduced conduction velocity (by 4% ± 4%) in the cooled region. Ventricular tachycardias (VTs) induced during regional cooling terminated earlier than those without cooling (control): VTs lasting >30 seconds were reduced from 17 of 39 to 1 of 61. When regional cooling was applied during sustained VTs (>120 seconds), 16 of 33 (48%) sustained VTs self-terminated in 12.5 ± 5.1 seconds. VT termination was the result of rotor destabilization, which was characterized by unpinning, drift toward the periphery of the cooled region, and subsequent collision with boundaries. The DC shock intensity required for cardioversion of the sustained VTs decreased significantly by regional cooling (22.8 ± 4.1 V, n = 16, vs 40.5 ± 17.6 V, n = 21). The major mode of reentry termination by DC shocks was phase resetting in the absence of cooling, whereas it was unpinning in the presence of cooling. Regional cooling facilitates termination of 2-D reentry through unpinning of rotors.

Original languageEnglish
Pages (from-to)107-114
Number of pages8
JournalHeart Rhythm
Volume9
Issue number1
DOIs
Publication statusPublished - 01-01-2012
Externally publishedYes

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Ventricular Tachycardia
Rabbits
Shock
Action Potentials
Electric Countershock
Myocardium
Equipment and Supplies

All Science Journal Classification (ASJC) codes

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Yamazaki, Masatoshi ; Honjo, Haruo ; Ashihara, Takashi ; Harada, Masahide ; Sakuma, Ichiro ; Nakazawa, Kazuo ; Trayanova, Natalia ; Horie, Minoru ; Kalifa, Jérme ; Jalife, José ; Kamiya, Kaichiro ; Kodama, Itsuo. / Regional cooling facilitates termination of spiral-wave reentry through unpinning of rotors in rabbit hearts. In: Heart Rhythm. 2012 ; Vol. 9, No. 1. pp. 107-114.
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title = "Regional cooling facilitates termination of spiral-wave reentry through unpinning of rotors in rabbit hearts",
abstract = "Moderate global cooling of myocardial tissue was shown to destabilize 2-dimensional (2-D) reentry and facilitate its termination. This study sought to test the hypothesis that regional cooling destabilizes rotors and facilitates termination of spontaneous and DC shock-induced subepicardial reentry in isolated, endocardially ablated rabbit hearts. Fluorescent action potential signals were recorded from 2-D subepicardial ventricular myocardium of Langendorff-perfused rabbit hearts. Regional cooling (by 5.9°C ± 1.3°C) was applied to the left ventricular anterior wall using a transparent cooling device (10 mm in diameter). Regional cooling during constant stimulation (2.5 Hz) prolonged the action potential duration (by 36{\%} ± 9{\%}) and slightly reduced conduction velocity (by 4{\%} ± 4{\%}) in the cooled region. Ventricular tachycardias (VTs) induced during regional cooling terminated earlier than those without cooling (control): VTs lasting >30 seconds were reduced from 17 of 39 to 1 of 61. When regional cooling was applied during sustained VTs (>120 seconds), 16 of 33 (48{\%}) sustained VTs self-terminated in 12.5 ± 5.1 seconds. VT termination was the result of rotor destabilization, which was characterized by unpinning, drift toward the periphery of the cooled region, and subsequent collision with boundaries. The DC shock intensity required for cardioversion of the sustained VTs decreased significantly by regional cooling (22.8 ± 4.1 V, n = 16, vs 40.5 ± 17.6 V, n = 21). The major mode of reentry termination by DC shocks was phase resetting in the absence of cooling, whereas it was unpinning in the presence of cooling. Regional cooling facilitates termination of 2-D reentry through unpinning of rotors.",
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Yamazaki, M, Honjo, H, Ashihara, T, Harada, M, Sakuma, I, Nakazawa, K, Trayanova, N, Horie, M, Kalifa, J, Jalife, J, Kamiya, K & Kodama, I 2012, 'Regional cooling facilitates termination of spiral-wave reentry through unpinning of rotors in rabbit hearts', Heart Rhythm, vol. 9, no. 1, pp. 107-114. https://doi.org/10.1016/j.hrthm.2011.08.013

Regional cooling facilitates termination of spiral-wave reentry through unpinning of rotors in rabbit hearts. / Yamazaki, Masatoshi; Honjo, Haruo; Ashihara, Takashi; Harada, Masahide; Sakuma, Ichiro; Nakazawa, Kazuo; Trayanova, Natalia; Horie, Minoru; Kalifa, Jérme; Jalife, José; Kamiya, Kaichiro; Kodama, Itsuo.

In: Heart Rhythm, Vol. 9, No. 1, 01.01.2012, p. 107-114.

Research output: Contribution to journalArticle

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T1 - Regional cooling facilitates termination of spiral-wave reentry through unpinning of rotors in rabbit hearts

AU - Yamazaki, Masatoshi

AU - Honjo, Haruo

AU - Ashihara, Takashi

AU - Harada, Masahide

AU - Sakuma, Ichiro

AU - Nakazawa, Kazuo

AU - Trayanova, Natalia

AU - Horie, Minoru

AU - Kalifa, Jérme

AU - Jalife, José

AU - Kamiya, Kaichiro

AU - Kodama, Itsuo

PY - 2012/1/1

Y1 - 2012/1/1

N2 - Moderate global cooling of myocardial tissue was shown to destabilize 2-dimensional (2-D) reentry and facilitate its termination. This study sought to test the hypothesis that regional cooling destabilizes rotors and facilitates termination of spontaneous and DC shock-induced subepicardial reentry in isolated, endocardially ablated rabbit hearts. Fluorescent action potential signals were recorded from 2-D subepicardial ventricular myocardium of Langendorff-perfused rabbit hearts. Regional cooling (by 5.9°C ± 1.3°C) was applied to the left ventricular anterior wall using a transparent cooling device (10 mm in diameter). Regional cooling during constant stimulation (2.5 Hz) prolonged the action potential duration (by 36% ± 9%) and slightly reduced conduction velocity (by 4% ± 4%) in the cooled region. Ventricular tachycardias (VTs) induced during regional cooling terminated earlier than those without cooling (control): VTs lasting >30 seconds were reduced from 17 of 39 to 1 of 61. When regional cooling was applied during sustained VTs (>120 seconds), 16 of 33 (48%) sustained VTs self-terminated in 12.5 ± 5.1 seconds. VT termination was the result of rotor destabilization, which was characterized by unpinning, drift toward the periphery of the cooled region, and subsequent collision with boundaries. The DC shock intensity required for cardioversion of the sustained VTs decreased significantly by regional cooling (22.8 ± 4.1 V, n = 16, vs 40.5 ± 17.6 V, n = 21). The major mode of reentry termination by DC shocks was phase resetting in the absence of cooling, whereas it was unpinning in the presence of cooling. Regional cooling facilitates termination of 2-D reentry through unpinning of rotors.

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