Mortazavi S, Park E, Florio J, Poore J, Bornzin G, Levine P A, Sholder J
Advanced Research Division, Pacesetter Inc., St. Jude Medical Company, Sylmar, California, USA.
Pacing Clin Electrophysiol. 1996 Nov;19(11 Pt 2):1678-81. doi: 10.1111/j.1540-8159.1996.tb03205.x.
Two advances in cardiac pacing have resulted in an internal conflict in some pacemakers. One is the development of a standard lead physiological sensor and the other is protection from electromagnetic interference (EMI). One popular type of standard lead sensor uses sub-threshold pulses to measure intracardiac and intrathoracic impedance changes, i.e., minute ventilation. Recent clinical observations and extensive in vitro testing have verified that digital cellular phones can be troublesome. Large feedthrough capacitors (FCs), effective in blocking the EMI, will preclude sensing of the standard impedance-based signals. A variety of pulse configurations were studied that might be effective for a sensor-based impedance signal while allowing the pacemaker to continue to use large Fcs protecting them from environmental EMI. In comparison to both monophasic and biphasic pulse sequences, a pentaphasic pulse sequence was effective as an impedance sensor, still allows large FCs to function as an effective filter for environmental EMI, and would not produce artifacts on surface ECG.
心脏起搏技术的两项进展在某些起搏器中引发了内部冲突。一是标准导联生理传感器的发展，另一是免受电磁干扰（EMI）的保护。一种常见的标准导联传感器利用亚阈值脉冲来测量心内和胸内阻抗变化，即分钟通气量。近期的临床观察和广泛的体外测试已证实，数字蜂窝电话可能会带来麻烦。大型穿通电容器（FC）虽能有效阻挡EMI，但会妨碍对基于标准阻抗信号的感知。研究了多种脉冲配置，它们可能对基于传感器的阻抗信号有效，同时允许起搏器继续使用大型FC来保护其免受环境EMI影响。与单相和双相脉冲序列相比，五相脉冲序列作为阻抗传感器是有效的，仍能让大型FC作为环境EMI的有效滤波器发挥作用，且不会在体表心电图上产生伪迹。
