In vivo mechanical study of helical cardiac pacing electrode interacting with canine myocardium

作     者：Xiangming Zhang Nianke Ma Hualin Fan Guodong Niu Wei Yang 

作者机构：Department of Engineering MechanicsTsinghua University Beijing 100084 China Fuwai Angiocardiopathy Hospital Beijing 100037 China Zhejiang University Hangzhou 310027 China 

出 版 物：《Acta Mechanica Sinica》 (力学学报（英文版）)

年 卷 期：2007年第23卷第3期

页      面：275-280页

核心收录：

学科分类：071011[理学-生物物理学] 0710[理学-生物学] 07[理学] 

基　　金：Acknowledgment The authors thank Dr. Zhang Shu and the animal lab in Beijing Fuwai Angiocardiopathy Hospital for their clinical supports and animal preparing. The authors greatly acknowledge the financial and facility supports from the Medtronic Cardiac Rhythm Management  USA  as well as the suggestion of Y. Zhao on conducting this research 

主　　题：Cardiac pacing Helical electrode Acute Interactions Myocardium 

摘      要：Cardiac pacing is a medical device to help human to overcome arrhythmia and to recover the regular beats of heart. A helical configuration of electrode tip is a new type of cardiac pacing lead distal tip. The helical electrode attaches itself to the desired site of heart by screwing its helical tip into the myocardium. In vivo experiments on anesthetized dogs were carried out to measure the acute interactions between helical electrode and myocardium during screw-in and pull-out processes. These data would be helpful for electrode tip design and electrode/myocardium adherence safety evaluation. They also provide reliability data for clinical site choice of human heart to implant and to fix the pacing lead. A special design of the helical tip using strain gauges is instrumented for the measurement of the screw-in and pull-out forces. We obtained the data of screw-in torques and pull-out forces for five different types of helical electrodes at nine designed sites on ten canine hearts. The results indicate that the screw-in torques increased steplike while the torque-time curves presente saw-tooth fashion. The maximum torque has a range of 0.3-1.9 Nmm. Obvious differences are observed for different types of helical tips and for different test sites. Large pull-out forces are frequently obtained at epicardium of left ventricle and right ventricle lateral wall, and the forces obtained at right ventricle apex and outflow tract of right ventricle are normally small. The differences in pull-out forces are dictated by the geometrical configuration of helix and regional structures of heart muscle.