The hibernator heart ? Nature's model of resistance to ventricular fibrillation

Johansson, Bengt W.

doi:10.1016/0008-6363(95)00192-1

Cited by 47 publications

(52 citation statements)

References 21 publications

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“…How is the hibernator's heart different from other hearts? Johansson (1996) answers with the following list: a different adrenergic innervation, a lower melting point of lipids, different enzyme temperature curves, and protection against calcium overload.…”

Section: Biological Rhythm Research 435mentioning

confidence: 99%

QT intervals compared in small and large hibernators and humans

Folk

Dickson

Hunt

et al. 2008

Biological Rhythm Research

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Small hibernating animals experience cycles of deep hypothermia followed by rewarming and feeding. This contrasts with bears, which remain in hibernation for four to seven months, experiencing large reductions in energy metabolism and heart rate, and small reductions in core temperature, and do not eat, drink, urinate, or defecate throughout. We measured the QT interval (QT) of the electrocardiogram (EKG) to determine whether the hearts of bears behave electrophysiologically more like classic hibernators or nonhibernators. We compared EKGs from grizzly and polar bears with small hibernators (marmots) and humans. Animal data were obtained using implanted radio capsules. EKGs of non-dormant marmots were characterized by a shortened QT (0.07-0.14 s); this held for grizzly and polar bears (0.14-0.23 s), but not for humans (0.39 s). Thus, the QT of bears resembles that of small hibernators. At the same heart rate, the QT of non-dormant bears and marmots differs in winter and summer.

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Section: Biological Rhythm Research 435mentioning

confidence: 99%

QT intervals compared in small and large hibernators and humans

Folk

Dickson

Hunt

et al. 2008

Biological Rhythm Research

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“…A key phenomenon to be explained is the hibernator's heart ability to cope with lowering body temperature skipping fatal arrhythmia (Johansson 1996). Blood clotting times are dramatically increased during hibernation, thereby alleviating the risk of thrombus formation when blood flow is reduced.…”

Section: Homeostasismentioning

confidence: 99%

Hypometabolic induced state: a potential tool in biomedicine and space exploration

Malatesta

Biggiogera

Zancanaro

2006

Rev Environ Sci Biotechnol

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This paper will first review the issue of hypometabolism in mammals with a focus on the strategies these animals evolved to cope with life challenge in hostile environments (e.g., cold weather and/or shortage of food). The different types of natural hypometabolism (hibernation, torpor, winter sleep) will be briefly described as well as major adaptations in body temperature, and energy and cell metabolism. In the second part of this review the issue of inducing a hypometabolic state in mammals will be afforded with special attention paid to changes in body temperature and metabolism, regulation of gene expression and the possible role of hibernation inducing factors. Finally, an overview of the potential of inducing a hypometabolic state in the human as related to the broad field of biomedicine will be given.

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“…Elle peut être responsable de complications rythmiques cardiaques pouvant conduire au décès du patient. En effet, l'activité métabolique et électrique du coeur est fortement modifiée par l'hypothermie : le seuil arythmogène ventriculaire s'abaisse lorsque la température est inférieure à 32 8C, ce qui est à l'origine d'une hyperexcitabilité et d'un risque important de fibrillation ventriculaire (FV) [1,[3][4][5][6]. L'utilisation de catécholamines peut également conduire à ce type de complication, en particulier la noradrénaline dont seuls les effets adverses arythmogènes sont obtenus, la vasoconstriction étant déjà majeure chez le patient en hypothermie [2,7].…”

Section: Fibrillation Ventriculaire à Petites Mailles Survenant Au Counclassified

“…Cependant, le réchauffement à lui seul peut conduire à des troubles du rythme [2,7]. Par ailleurs, des travaux réalisés sur des animaux hibernants, apparemment protégés contre la survenue de FV, trouvent que la résistance à la FV est d'autant plus importante que les durées de l'intervalle QT et du potentiel d'action sont plus courtes [5]. Chez l'homme en situation d'hypothermie modérée ou sévère, la durée de l'intervalle QT et du potentiel d'action est allongée [2,4].…”

Section: Fibrillation Ventriculaire à Petites Mailles Survenant Au Counclassified