Lee Kathy L, Lau Chu-Pak, Tse Hung-Fat, Echt Debra S, Heaven David, Smith Warren, Hood Margaret
Cardiology Division, Department of Medicine, University of Hong Kong, Hong Kong SAR, China.
J Am Coll Cardiol. 2007 Aug 28;50(9):877-83. doi: 10.1016/j.jacc.2007.04.081. Epub 2007 Aug 13.
The purpose of this study was to evaluate the feasibility and safety of a novel technology that uses energy transfer from an ultrasound transmitter to achieve cardiac stimulation without the use of a pacing lead in humans.
To overcome the limitations of pacemaker leads, a new technology enabling stimulation without the use of a lead is desirable.
A steerable bipolar electrophysiology catheter incorporating a receiver electrode into the tip and circuitry to convert ultrasound energy to electrical energy was inserted transvenously into the heart. An ultrasound transmitting transducer was placed on the chest wall with ultrasound gel. Ultrasound energy was amplitude-adjusted and transmitted at 313 to 385 kHz. The output waveform of the receiver electrode was monitored while the transmitter was moved on the chest wall to target the receiver. The ultrasound transmission amplitude was limited to a mechanical index of 1.9, the maximum allowed for ultrasound imaging systems. Ultrasound-mediated pacing with minimum voltage but consistent capture was obtained for 12 s.
Twenty-four patients (48 +/- 12 years) were tested during or after completion of clinical electrophysiology procedures. A total of 80 pacing sites were tested (mean 3.3 sites/patient): 12 right atrial, 35 right ventricular, and 33 left ventricular (31 endocardial) sites. The transmit-to-receive distance was 11.3 +/- 3.2 cm (range 5.3 to 22.5 cm). Ultrasound-mediated pacing was achieved at all 80 test sites, with consistent capture at 77 sites. The mechanical index during pacing was 0.5 +/- 0.3 (range 0.1 to 1.5). The mean ultrasound-mediated capture threshold was 1.01 +/- 0.64 V. There was no adverse event related to ultrasound pacing. No patient experienced discomfort during pacing.
The feasibility and safety of pacing usng ultrasound energy has been shown acutely.
本研究旨在评估一种新技术的可行性和安全性，该技术利用超声发射器的能量传递在人体中实现心脏刺激而无需使用起搏导线。
为克服起搏器导线的局限性，需要一种无需使用导线即可实现刺激的新技术。
将一根可操纵的双极电生理导管经静脉插入心脏，该导管在尖端集成了接收电极以及将超声能量转换为电能的电路。在胸壁上涂抹超声凝胶后放置一个超声发射换能器。超声能量进行幅度调整后以313至385kHz的频率发射。当发射器在胸壁上移动以对准接收器时，监测接收电极的输出波形。超声发射幅度限制在机械指数1.9，这是超声成像系统允许的最大值。获得了持续12秒的超声介导起搏，且电压最低但捕获稳定。
24例患者（48±12岁）在临床电生理检查期间或结束后接受了测试。共测试了80个起搏部位（平均每位患者3.3个部位）：12个右心房部位、35个右心室部位和33个左心室部位（31个心内膜部位）。发射端到接收端的距离为11.3±3.2cm（范围为5.3至22.5cm）。在所有80个测试部位均实现了超声介导起搏，77个部位捕获稳定。起搏期间的机械指数为0.5±0.3（范围为0.1至1.5）。超声介导的平均捕获阈值为1.01±0.64V。未发生与超声起搏相关的不良事件。起搏期间无患者感到不适。
已急性证明了使用超声能量进行起搏的可行性和安全性。
