Kirchhof C J, Bonke F I, Allessie M A, Roos A G, Lammers W J
Department of Physiology, University of Limburg, Maastricht, The Netherlands.
J Cardiovasc Pharmacol. 1988 Jun;11(6):667-75. doi: 10.1097/00005344-198806000-00006.
The sinus node is not only important for the generation of the cardiac impulse but also as conductor of this impulse from the site of origin toward the atrium. An easy method to investigate conduction properties of sinus nodal tissue directly is described. The isolated right atrium of the rabbit was divided--via an incision perpendicular to the crista terminalis--into two halves connected only by a bridge of sinus nodal tissue. By means of two atrial surface electrodes conduction through the sinus node bridge was monitored. It appeared that conduction in the sino-atrial border zone is many times slower than in the atrium and refractory period markedly longer. In the center of the sinus node conduction is again slower and refractory period longer than in the border zone. Validity of the method was tested by reconstruction of the conduction route of stimulated impulses using microelectrode recordings. Applications of the method were demonstrated by studying the effects of rate and rhythm, hypothermia, hypoxia, acetylcholine and norepinephrine as well as verapamil. The model is suitable for investigation of the effects of drugs and other interventions on impulse conduction in sinus nodal tissue.
窦房结不仅对心脏冲动的产生很重要，而且对该冲动从起源部位向心房的传导也很重要。本文描述了一种直接研究窦房结组织传导特性的简便方法。通过垂直于终嵴的切口将兔离体右心房分为两半，两半仅通过窦房结组织桥相连。借助两个心房表面电极监测通过窦房结桥的传导。结果显示，窦房交界区的传导速度比心房慢很多倍，且不应期明显更长。在窦房结中心，传导再次减慢，不应期比交界区更长。通过使用微电极记录重建刺激冲动的传导途径来测试该方法的有效性。通过研究心率和节律、低温、缺氧、乙酰胆碱、去甲肾上腺素以及维拉帕米的影响来证明该方法的应用。该模型适用于研究药物和其他干预措施对窦房结组织冲动传导的影响。
