Department of Clinical Therapeutics, Medical School, University of Athens, Alexandra Hospital, Athens, Greece.
Resuscitation. 2011 Feb;82(2):207-12. doi: 10.1016/j.resuscitation.2010.10.006. Epub 2010 Nov 4.
The early appearance of ventricular fibrillation (VF) following acute myocardial infarction (MI) is associated with adrenergic effects and electrical interactions although some early "mechanical" changes may also occur. The aim of the present experimental study was to examine whether early changes in the functional geometry of left ventricular (LV) contraction may be associated with ventricular arrhythmias occurring during the first 120min of MI.
In 11 swine left anterior descending (LAD) coronary artery ligation was performed. Aortic flow, LV end-diastolic pressure (LVEDP), LV long and short axis lengths were measured and their fractional shortening (FS) was calculated before and during the initial 120min period of MI.
LV long axis FS and aortic flow decreased (p<0.001) whereas LVEDP increased (p<0.01) in all 11 animals within 30min following LAD ligation. LV long and short axis lengths and LV short axis FS did not change significantly. VF occurred in 5 of the 11 animals within this 30min period. LV short axis FS decreased (p<0.05) in all 5 animals prior to VF and increased (p<0.05) in all 6 animals without VF. In 3 of the 6 animals that had no VF during the initial 30min VF occurred later. Similarly, LV short axis FS decreased prior to VF in all those 3 animals. LV short axis FS did not decrease in any of the remaining 3 swine without VF during the same period of time.
Early changes in the functional geometry of LV contraction, in the form of a reduction of LV short axis FS, are associated with a greater incidence of VF in experimental acute MI.
急性心肌梗死（MI）后早期出现心室颤动（VF）与儿茶酚胺作用和电相互作用有关，尽管可能也会发生一些早期的“机械”变化。本实验研究的目的是检验左心室（LV）收缩功能几何形状的早期变化是否与 MI 后前 120 分钟内发生的室性心律失常有关。
在 11 头猪中进行左前降支（LAD）冠状动脉结扎。在 MI 的最初 120 分钟内测量主动脉流量、LV 舒张末期压（LVEDP）、LV 长轴和短轴长度，并计算其缩短分数（FS）。
在 LAD 结扎后 30 分钟内，所有 11 只动物的 LV 长轴 FS 和主动脉流量均降低（p<0.001），而 LVEDP 升高（p<0.01）。LV 长轴和短轴长度以及 LV 短轴 FS 无明显变化。在这 30 分钟内，5 只动物发生 VF。在所有 5 只发生 VF 的动物中，LV 短轴 FS 在 VF 前降低（p<0.05），而在所有 6 只无 VF 的动物中增加（p<0.05）。在无 VF 的 6 只动物中有 3 只动物的 VF 发生较晚。同样，在这 3 只动物中，LV 短轴 FS 在 VF 前均降低。在同一时间段内，无 VF 的其余 3 头猪的 LV 短轴 FS 并未降低。
LV 收缩功能几何形状的早期变化，以 LV 短轴 FS 的降低为特征，与实验性急性 MI 中 VF 的发生率增加有关。
