局部给药跨室壁氯化钾单相动作电位记录电极的研制

目的研制局部给药跨室壁氯化钾单相动作电位(MAP)记录电极(KC lMAP电极),探讨模拟在体犬交感神经不均一的致心律失常机制。方法由5F动脉鞘管和0.2 mm的绝缘银丝,组构成3对MAP记录电极,鞘芯腔内注入含30%氯化钾琼脂糖凝胶即制成KC lMAP电极。用自制的电极记录犬左室前壁跨室壁MAP,观察局部异丙肾上腺素对三层心肌细胞动作电位时程(APD)及跨室壁复极离散度(TDR)的影响和心律失常的诱发情况。结果KC lMAP电极能稳定记录三层心肌MAP 120 m in以上,随时间的延长动作电位振幅逐渐降低但不影响复极特性的分析;局部给予异丙肾上腺素(10-5mg/m l)能显著降低中层心肌细胞的APD90(236.9±3.8 m s vs 226.3±3.0 m s)和TDR(35.7±4.8 m s vs 24.9±3.9 m s),中层心肌细胞易于诱发早期后除极及触发活动并引起室性心律失常。结论KC lMAP电极可理想地用于跨室壁心肌复极特性的研究;异丙肾上腺素降低正常犬的TDR,其诱发室性心律失常的机制与后除极和触发活动有关。

Researches on potassium chloride transmural recording electrode of monophasic action potential with local administration of agents

Objective To design a kind of monophasic action potential(MAP) recording electrode(KCl MAP electrode) which has the capability of local agent administration and to probe into the arrhythmogenic mechanism of sympathetic heterogeneity of canine in vivo.Methods The KCl MAP electrode with three pair of electrodes was made up of 5F arterial sheath and insulated silver thread(0.2mm in diameter),and the low melting point agarose gel containing 30% of potassium chloride was immitted into the core of the sheath.Transmural MAP of canine in vivo was recorded with the self-made KCl MAP electrode;the impact of local Isoprenaline on action potential duration(APD) of three layer myocardium,transmural dispersion of repolarization(TDR) and the inducing of ventricular arrhythmia were researched.Results Transmural MAP could be recorded by the KCl MAP electrode more than 120 minutes with the amplitude of action potential(APA) decreasing gradually but the analysis of the repolarization character not being affected.The APD of mid-myocardial(236.9±3.8 ms vs 226.3±3.0 ms) and TDR(35.7±4.8 ms vs 24.9±3.9 ms) were decreased remarkably by Isoprenaline(10~(-5) mg/ml).Ventricular arrhythmia induced by early after-depolarization and triggered activity was prone to incurred at mid-myocardial.Conclusions It is an ideal method for the KCl MAP electrode to be applied to the researches of transmural repolarization;TDR could be decreased by Isoprenaline and the mechanism of ventricular arrhythmia incurred by Isoprenaline is related to after-depolarization and triggered activity.[Chinese Journal of Cardiac Pacing and Electrophysiology,2006,20(1):53~57 ]