Schaldach M
Zentralinstitut für Biomedizinische Technik, Friedrich-Alexander-Universität, Erlangen, Germany.
Med Prog Technol. 1995;21(1):1-16.
The interaction of the autonomic nervous system (ANS) and the heart is characterized by a new interdisciplinary field known as neurocardiology which presents the newest strategy for electro-cardiostimulation. In this context, the reestablishment of chronotropy with physiological, closed-loop pacing, as well as the prevention and treatment of a malignant arrhythmia by ANS modulation, is of the highest priority. The main objective toward this goal consists of appropriate monitoring of the autonomic balance and stimulation, respectively, so that neuromodulation of the cardiac efferents can be established. The electrode, as a sensor and an actuator, with its interface on the cellular level becomes of essential importance. The electrode-myocardium interface is determined by the structure of the Helmholtz double layer with regard to its physical, electrochemical, and physiological behavior. The transportation of electrons across the boundary, as well as the electro-chemical reactions determining the biocompatibility of the interface, can be improved by the microstructure of the solid component by creating a fractal surface coating with titanium-nitride or iridium. Experimental and clinical results have demonstrated that the fractal structure ensures negligible polarization as well as improved detection performance, thus, detecting the evoked response of the myocardial cells makes it possible to monitor the neural response of the myocardium as a consequence of a superimposed chronotropic disturbance. The stimulation electrode also monitors the sympathetic activity extracted from intracardiac impedance measurements, thereby providing a new principle of rate adaptation in which the pacemaker is an integral part of the ANS, reestablishing normal chronotropy. Further advantages of the improved electrode interface performance open new aspects in the treatment and prevention of tachyarrhythmia, and in the follow-up of transplanted hearts for the prevention of the rejection processes.
自主神经系统（ANS）与心脏的相互作用以一个名为神经心脏病学的新跨学科领域为特征，该领域提出了最新的心脏电刺激策略。在这种背景下，通过生理性闭环起搏恢复变时性，以及通过ANS调节预防和治疗恶性心律失常，是最优先考虑的事项。实现这一目标的主要目的分别在于对自主平衡和刺激进行适当监测，以便能够建立对心脏传出神经的神经调节。电极作为传感器和执行器，其在细胞水平上的界面变得至关重要。电极 - 心肌界面在其物理、电化学和生理行为方面由亥姆霍兹双层结构决定。通过用氮化钛或铱创建分形表面涂层来改善固体成分的微观结构，可以改善电子跨边界的传输以及决定界面生物相容性的电化学反应。实验和临床结果表明，分形结构确保了可忽略不计的极化以及改进的检测性能，因此，检测心肌细胞的诱发反应使得监测由于叠加的变时性干扰而导致的心肌神经反应成为可能。刺激电极还监测从心内阻抗测量中提取的交感神经活动，从而提供一种新的心率适应原理，其中起搏器是ANS的一个组成部分，可恢复正常变时性特性。改进的电极界面性能的进一步优势为治疗和预防快速性心律失常以及在移植心脏随访中预防排斥反应过程开辟了新的方面。
