Cardiac adaptation in hibernating, free-ranging Scandinavian Brown Bears (Ursus arctos).

ABSTRACT: During six months of annual hibernation, the brown bear undergoes unique physiological changes to adapt to decreased metabolic rate. We compared cardiac structural and functional measures of hibernating and active bears using comprehensive echocardiography. We performed echocardiography on 13 subadult free-ranging, anaesthetised Scandinavian brown bears (Ursus arctos) during late hibernation and in early summer. Mean heart rate was 26 beats per minute (standard deviation (SD): 8) during hibernation vs 71 (SD: 14) during active state. All left ventricular (LV) systolic and diastolic measures were decreased during hibernation: mean ejection fraction: 44.2% (SD: 6.0) active state vs 34.0 (SD: 8.1) hibernation, P?=?0.001; global longitudinal strain: -11.2% (SD: 2.0) vs -8.8 (SD: 3.3), P?=?0.03; global longitudinal strain rate: -0.82 (SD: 0.15) vs -0.41 (SD: 0.18), P?

SUBMITTER: Jorgensen PG 

PROVIDER: S-EPMC6959366 | biostudies-literature | 2020 Jan

REPOSITORIES: biostudies-literature