Dynamicity of hypothermia-induced J waves and the mechanism involved

Yoshifusa Aizawa, Yukio Hosaka, Hirotaka Oda, Koichi Fuse, Masaaki Okabe, Yoshiaki Kaneko, Naohiko Takahashi, Hirofumi Zaizen, Yoshiyasu Aizawa, Keiichi Fukuda

Research output: Contribution to journalArticle

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Abstract

Background: J waves develop during hypothermia, but the dynamicity of hypothermia-induced J waves is poorly understood. Objective: The purpose of this study was to investigate the mechanism of the rate-dependent change in the amplitude of hypothermia-induced J waves. Methods: Nineteen patients with severe hypothermia were included (mean age 70 ± 12 years; 16 men [84.2%]). The rectal temperature at the time of admission was 27.8° ± 2.5°C. In addition to prolonged PR, QRS complex, and corrected QT intervals, the distribution of prominent J waves was widespread in all 19 patients. Results: Nine patients showed changes in RR intervals. When the RR interval shortened from 1353 ± 472 to 740 ± 391 ms (P =.0002), the J-wave amplitude increased from 0.50 ± 0.29 to 0.61 ±0.27 mV (P =.0075). The J-wave amplitude increased in 7 patients (77.8%) and decreased in 2 patients (22.2%) after short RR intervals. The augmentation of J waves at short RR intervals was associated with a significant prolongation of ventricular activation time (35 ± 5 ms vs 46 ± 5 ms; P =.0020), suggesting accentuated conduction delay. Increased conduction delay at short RR intervals was suggested to accentuate the phase 1 notch of the action potential and J waves in hypothermia. None developed ventricular fibrillation, and in 2 of 9 patients with atrial fibrillation, atrial fibrillation persisted after rewarming to normothermia. Conclusion: J waves in severe hypothermia were augmented after short RR intervals in 7 patients as expected for depolarization abnormality, whereas 2 patients showed a bradycardia-dependent augmentation as expected for transient outward current–mediated J waves. Increased conduction delay at short RR intervals can be responsible for the accentuation of the transient outward current and J waves during severe hypothermia.

Original languageEnglish
Pages (from-to)74-80
Number of pages7
JournalHeart Rhythm
Volume16
Issue number1
DOIs
Publication statusPublished - 2019 Jan 1

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Induced Hypothermia
Hypothermia
Atrial Fibrillation
Radio Waves
Rewarming
Ventricular Fibrillation
Bradycardia
Action Potentials
Temperature

Keywords

  • Hypothermia
  • J waves
  • J-wave amplitude
  • Osborn waves
  • Rate dependency

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Physiology (medical)

Cite this

Dynamicity of hypothermia-induced J waves and the mechanism involved. / Aizawa, Yoshifusa; Hosaka, Yukio; Oda, Hirotaka; Fuse, Koichi; Okabe, Masaaki; Kaneko, Yoshiaki; Takahashi, Naohiko; Zaizen, Hirofumi; Aizawa, Yoshiyasu; Fukuda, Keiichi.

In: Heart Rhythm, Vol. 16, No. 1, 01.01.2019, p. 74-80.

Research output: Contribution to journalArticle

Aizawa, Y, Hosaka, Y, Oda, H, Fuse, K, Okabe, M, Kaneko, Y, Takahashi, N, Zaizen, H, Aizawa, Y & Fukuda, K 2019, 'Dynamicity of hypothermia-induced J waves and the mechanism involved', Heart Rhythm, vol. 16, no. 1, pp. 74-80. https://doi.org/10.1016/j.hrthm.2018.07.024
Aizawa Y, Hosaka Y, Oda H, Fuse K, Okabe M, Kaneko Y et al. Dynamicity of hypothermia-induced J waves and the mechanism involved. Heart Rhythm. 2019 Jan 1;16(1):74-80. https://doi.org/10.1016/j.hrthm.2018.07.024
Aizawa, Yoshifusa ; Hosaka, Yukio ; Oda, Hirotaka ; Fuse, Koichi ; Okabe, Masaaki ; Kaneko, Yoshiaki ; Takahashi, Naohiko ; Zaizen, Hirofumi ; Aizawa, Yoshiyasu ; Fukuda, Keiichi. / Dynamicity of hypothermia-induced J waves and the mechanism involved. In: Heart Rhythm. 2019 ; Vol. 16, No. 1. pp. 74-80.
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abstract = "Background: J waves develop during hypothermia, but the dynamicity of hypothermia-induced J waves is poorly understood. Objective: The purpose of this study was to investigate the mechanism of the rate-dependent change in the amplitude of hypothermia-induced J waves. Methods: Nineteen patients with severe hypothermia were included (mean age 70 ± 12 years; 16 men [84.2{\%}]). The rectal temperature at the time of admission was 27.8° ± 2.5°C. In addition to prolonged PR, QRS complex, and corrected QT intervals, the distribution of prominent J waves was widespread in all 19 patients. Results: Nine patients showed changes in RR intervals. When the RR interval shortened from 1353 ± 472 to 740 ± 391 ms (P =.0002), the J-wave amplitude increased from 0.50 ± 0.29 to 0.61 ±0.27 mV (P =.0075). The J-wave amplitude increased in 7 patients (77.8{\%}) and decreased in 2 patients (22.2{\%}) after short RR intervals. The augmentation of J waves at short RR intervals was associated with a significant prolongation of ventricular activation time (35 ± 5 ms vs 46 ± 5 ms; P =.0020), suggesting accentuated conduction delay. Increased conduction delay at short RR intervals was suggested to accentuate the phase 1 notch of the action potential and J waves in hypothermia. None developed ventricular fibrillation, and in 2 of 9 patients with atrial fibrillation, atrial fibrillation persisted after rewarming to normothermia. Conclusion: J waves in severe hypothermia were augmented after short RR intervals in 7 patients as expected for depolarization abnormality, whereas 2 patients showed a bradycardia-dependent augmentation as expected for transient outward current–mediated J waves. Increased conduction delay at short RR intervals can be responsible for the accentuation of the transient outward current and J waves during severe hypothermia.",
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AU - Aizawa, Yoshifusa

AU - Hosaka, Yukio

AU - Oda, Hirotaka

AU - Fuse, Koichi

AU - Okabe, Masaaki

AU - Kaneko, Yoshiaki

AU - Takahashi, Naohiko

AU - Zaizen, Hirofumi

AU - Aizawa, Yoshiyasu

AU - Fukuda, Keiichi

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AB - Background: J waves develop during hypothermia, but the dynamicity of hypothermia-induced J waves is poorly understood. Objective: The purpose of this study was to investigate the mechanism of the rate-dependent change in the amplitude of hypothermia-induced J waves. Methods: Nineteen patients with severe hypothermia were included (mean age 70 ± 12 years; 16 men [84.2%]). The rectal temperature at the time of admission was 27.8° ± 2.5°C. In addition to prolonged PR, QRS complex, and corrected QT intervals, the distribution of prominent J waves was widespread in all 19 patients. Results: Nine patients showed changes in RR intervals. When the RR interval shortened from 1353 ± 472 to 740 ± 391 ms (P =.0002), the J-wave amplitude increased from 0.50 ± 0.29 to 0.61 ±0.27 mV (P =.0075). The J-wave amplitude increased in 7 patients (77.8%) and decreased in 2 patients (22.2%) after short RR intervals. The augmentation of J waves at short RR intervals was associated with a significant prolongation of ventricular activation time (35 ± 5 ms vs 46 ± 5 ms; P =.0020), suggesting accentuated conduction delay. Increased conduction delay at short RR intervals was suggested to accentuate the phase 1 notch of the action potential and J waves in hypothermia. None developed ventricular fibrillation, and in 2 of 9 patients with atrial fibrillation, atrial fibrillation persisted after rewarming to normothermia. Conclusion: J waves in severe hypothermia were augmented after short RR intervals in 7 patients as expected for depolarization abnormality, whereas 2 patients showed a bradycardia-dependent augmentation as expected for transient outward current–mediated J waves. Increased conduction delay at short RR intervals can be responsible for the accentuation of the transient outward current and J waves during severe hypothermia.

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KW - J-wave amplitude

KW - Osborn waves

KW - Rate dependency

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