Myocardial anisotropy and cardiac arrhythmias

急性缺血对纵向（VL）和横向（VT）纤维轴的传导速度的影响，确定从心外膜激动模式，记录48个双极电极的左前和后心室壁。在控制状态期间，VL大于VT，表明心肌的各向异性特性。急性缺血时，前壁和后壁的VL和VT均较对照值降低，VT的降低程度大于VL，导致VL/T升高。这种增强的各向异性心室传导可能与急性缺血时室性心律失常的发生有关。

The effects of acute ischemia on conduction velocites in the longitudinal (VL) and transverse (VT) fiber axis were determined from epicardial activation patterns, recorded with 48 bipolar electrodes on the left anterior and posterior canine ventricular wall. During the control state VL was greater than VT demonstrating anisotropic properties of cardiac muscle. During acute ischemia VL and VT were decreased from the control value and VT was decreased greater extent than VL resulting in an increase in VL/T in both anterior and posterior wall. This augumented anisotropic ventricular conduction may have some relation to the initiation of ventricular arrhythmias during acute ischemia.