极快速减压时兔心电图及心脏病理学改变

Changes in electrocardiogram and pathology of exposed rabbits following rush decompression

目的实时观察极快速减压致兔死亡过程中兔心电图及心脏病理学变化，探讨这一减压和低压暴露过程对兔心功能的影响。方法6只成年雄性新西兰兔，逐只置入低压舱内，在1min内使舱内压力由100kPa（常压）降至15kPa，维持此压力至兔死亡后出舱。全程记录肢体导联，将兔进舱前心电图图谱作为对照。将动物取出舱后立即解剖，取心脏作常规病理切片，行组织学检查。结果兔在极快速减压初期出现短暂的心率加快伴挣扎，而后心率逐渐减慢，P—R间期和Q—T间期明显延长，出现严重房室传导阻滞或者室性心律紊乱，其中1只出现S-T段下移，最后因完全性房室传导阻滞合并心室停搏而死亡。病理切片显示：极快速减压后死亡兔心肌细胞大面积坏死、崩解。结论极快速减压可使兔心脏发生严重的结构与功能损伤，产生传导阻滞而猝死，这可能是快速减压和急性缺氧双重作用的结果。

Objective To make real time observation of the changes in ECG and cardiopathology in rabbits and also to investigate effects of hypobaric exposure and rush decompression on the heart structure and function of the exposed animals. Methods Six adult male New Zealand rabbits were placed in the hypobaric chamber, decompressed from 100 kPa to 15 kPa within lmin and kept at that pressure until the animals died. Limb leads were recorded consecutively. ECG icon recorded before entrance of the chamber was used as control. The sacrificed animals were immediately anatomized and heart tissues taken for histology under the microscope as soon as the rabbits were taken from the chamber. Results The animals all experienced temporal increased heart rate coupled with struggling. Then, heart rate decreased gradually and, P-R and Q-T intervals extended significantly. The rabbits experienced serious atrioventricular block or ventricular arrhythmias with S-T segment decreased in one of the animah. Finally, the animal died due to complete atrioventricular block accompanied with ventricular standstill. Pathological examination showed that extensive necrosis and disintegration of cadiocytes were present in the heart tissue of the animals that died following rush decompression. Conclusions Rush decompression could cause serious impairment of the heart and sudden death due to lethal conduction blockade, which might be attributed to both rush decompression and acute hypoxia.