Goshka S L, Azarov J E, Chamkin S M, Kunevitch M P, Shmakov D N
Institute of Physiology, Komi Research Center, Ural Division of the Russian Academy of Sciences, Syktyvkar, Russia.
Bull Exp Biol Med. 2009 Jun;147(6):679-82. doi: 10.1007/s10517-009-0606-z.
The duration of repolarization of subendocardial, intramural, and epicardial layers of dog ventricles was studied under conditions of volume overload of the heart in situ. Increased preload was modeled by rapid intravenous infusion of saline and rheopolygluquine. The activation-recovery interval was measured by flexible intramural electrodes inserted into the right and left ventricles. The level of preload was evaluated by the increase in left-ventricular end-diastolic pressure. The increase in preload from 11+/-6 to 26+/-10 mm Hg led to a significant (p<0.05) prolongation of the activation-recovery interval in the subepicardial layers of apex, all layers of the lateral wall, and subepicardial and intramural layers of the base of the left ventricle and in subendocardial layers of the apex and base of the right ventricle. Further elevation of the end-diastolic pressure to 34+/-11 mm Hg led to shortening of the activation-recovery interval (p<0.05) in the subepicardial layers of the apex and lateral wall of the left ventricle and in the subepicardial layers of right-ventricular base and left-ventricular lateral wall. Hence, different areas of the myocardium differently react to volume overload of the heart. Changes in repolarization length in response to preload increase are biphasic.
在犬原位心脏容量超负荷的情况下，研究了犬心室心内膜下、心肌中层和心外膜层的复极持续时间。通过快速静脉输注生理盐水和低分子右旋糖酐来模拟增加前负荷。采用插入右心室和左心室的柔性心肌内电极测量动作电位激活-恢复间期。通过左心室舒张末期压力的升高来评估前负荷水平。前负荷从11±6 mmHg增加到26±10 mmHg，导致左心室心尖的心外膜下层、侧壁各层、心底的心外膜下和心肌中层以及右心室心尖和心底的心内膜下层的动作电位激活-恢复间期显著延长（p<0.05）。舒张末期压力进一步升高至34±11 mmHg，导致左心室心尖和侧壁的心外膜下层以及右心室心底和左心室侧壁的心外膜下层的动作电位激活-恢复间期缩短（p<0.05）。因此，心肌的不同区域对心脏容量超负荷的反应不同。复极长度随前负荷增加的变化是双相的。
