Tseng C D, Tseng Y Z, Carson W, Lo H M, Hsu K L, Chiang F T, Wu T L
Department of Internal Medicine, National Taiwan University Hospital, Taipei, R.O.C.
Jpn Heart J. 1995 May;36(3):349-65. doi: 10.1536/ihj.36.349.
The objectives of this study were to examine the serial vectorcardiographic changes following acute myocardial infarct and to assess the relationship between QRS loop changes and infarct size. Fifty adult male Long-Evans rats of 250-350 gm body weight were used to study experimental acute myocardial infarction induced by coronary artery ligation. Vectorcardiograms (VCG) of the Frank lead system were recorded before, and 1 day and 7 days after operation. Animals were sacrificed on the 7th day for histological quantitation of infarct area ratios. We found that (1) before operation, rats have ST elevation, probably due to early repolarization. (2) After coronary artery ligation, ECG showed characteristic dome-shaped ST elevation at 1 hr after ligation which returned to normal during the first day. Abnormal Q waves appeared thereafter. (3) After ligation, maximum QRS vector, ST vector and maximum T vector were reduced in magnitude the first day and recovered by the 7th day. The vectors tended to shift their direction to the right and to the posterior. QRS-T angle, however, widened as time went on. About half of the rats revealed changes in the inscription direction of the QRS loop and abnormal QRS morphology also appeared in about half of the ligated rats. (4) Those in whom abnormal QRS loop morphology and/or biting appeared had significantly larger infarct area ratios (p < 0.01). (5) Change in QRS loop inscription direction seemed not to be related to the infarct size. (6) In the LS plane, the difference in max QRS vector magnitude between the 1st and 7th days significantly correlated with the infarct area ratio (r = 0.533, p < 0.05). In the H plane, the change in the max QRS vector magnitude at the 7th day correlated with the infarct area ratio (r = -0.531, p < 0.05). In the F plane, changes in the direction of the max QRS vector were significantly correlated to the infarct area ratio both on the first (r = 0.431, p < 0.05) and 7th days (r = 0.531, p < 0.05). It is concluded that the VCG, like the ECG, had evolutional changes in AMI and that the QRS loop seen on vectorcardiography has only a slight correlation with the histological myocardial infarct size.
本研究的目的是检查急性心肌梗死后连续的心向量图变化，并评估QRS环变化与梗死面积之间的关系。选用50只体重250 - 350克的成年雄性Long-Evans大鼠来研究冠状动脉结扎诱导的实验性急性心肌梗死。在手术前、术后1天和7天记录Frank导联系统的心向量图（VCG）。在第7天处死动物以进行梗死面积比的组织学定量分析。我们发现：（1）手术前，大鼠存在ST段抬高，可能是由于早期复极。（2）冠状动脉结扎后，心电图显示结扎后1小时出现特征性的圆顶状ST段抬高，在第一天内恢复正常。此后出现异常Q波。（3）结扎后，最大QRS向量、ST向量和最大T向量在第一天幅度减小，并在第7天恢复。这些向量的方向倾向于向右和向后移位。然而，QRS - T角随时间推移而增宽。约一半的大鼠显示QRS环的 inscription方向改变，约一半的结扎大鼠也出现异常QRS形态。（4）出现异常QRS环形态和/或biting的大鼠梗死面积比显著更大（p < 0.01）。（5）QRS环 inscription方向的改变似乎与梗死面积无关。（6）在LS平面，第1天和第7天最大QRS向量幅度的差异与梗死面积比显著相关（r = 0.533，p < 0.05）。在H平面，第7天最大QRS向量幅度的变化与梗死面积比相关（r = -0.531，p < 0.05）。在F平面，最大QRS向量方向的变化在第1天（r = 0.431，p < 0.05）和第7天（r = 0.531，p < 0.05）均与梗死面积比显著相关。结论是，与心电图一样，心向量图在急性心肌梗死中有演变性变化，并且心向量图上看到
