Grong K, Stangeland L, Andersen K S, Lekven J
Cardiovasc Res. 1982 May;16(5):269-75. doi: 10.1093/cvr/16.5.269.
The beta-adrenergic blocking agent timolol was given to cats with acute coronary artery ligation under controlled haemodynamic conditions. Regional myocardial tissue flow was measured by the distribution of labelled microspheres. Timolol reduced cardiac contractility and left ventricular end-diastolic pressure rose, whereas heart rate and ventricular systolic pressure were kept constant by atrial pacing and aortic clamping. The systolic period increased following timolol administration under these conditions. Myocardial blood flow remained unchanged in central ischaemic and border areas, whereas flow increased both endocardially and epicardially in normally perfused area following timolol administration. Without pacing there was a significant flow reduction in the epicardium of the normally perfused area, compared with the situation where heart rate was constant. Under controlled haemodynamic conditions, therefore, timolol appears to improve coronary perfusion in normal myocardium, whereas blood flow to ischaemic myocardium remains essentially unchanged.
在可控的血流动力学条件下，给急性冠状动脉结扎的猫注射β-肾上腺素能阻滞剂噻吗洛尔。通过标记微球的分布来测量局部心肌组织血流量。噻吗洛尔降低了心脏收缩力，左心室舒张末期压力升高，而通过心房起搏和主动脉钳夹使心率和心室收缩压保持恒定。在这些条件下，注射噻吗洛尔后收缩期延长。在中央缺血区和边缘区，心肌血流量保持不变，而在注射噻吗洛尔后，正常灌注区的心内膜和心外膜血流量均增加。与心率恒定的情况相比，在没有起搏的情况下，正常灌注区的心外膜血流量显著减少。因此，在可控的血流动力学条件下，噻吗洛尔似乎能改善正常心肌的冠状动脉灌注，而缺血心肌的血流量基本保持不变。
