Walsh Sj S j, Manoharan G, Escalona Oj O j, Evans N, Allen Jd J d, Anderson J McC, Adgey Aa A a j
J Electrocardiol. 2003;36 Suppl:191-2. doi: 10.1016/j.jelectrocard.2003.09.057.
We investigated a novel device that delivered biphasic and monophasic shocks without tilt, in transvenous cardioversion of atrial fibrillation (AF). The device contains a radiofrequency (RF) transmitting primary, a 15mm air gap and a passive secondary unit that produces the required direct current waveform.
The device was assessed in 10 anaesthetised and ventilated sheep (65 +/- SD 12kg). Defibrillation leads were positioned in the distal coronary sinus and the lateral right atrium. The novel RF defibrillator was assessed using rectangular monophasic or biphasic pulses and compared to conventional (C) tilted waveforms (Ventritex HVS-02). During AF placebo shocks were delivered to a 50 Omega dummy load. Sustained AF was induced by rapid atrial pacing and 5 attempts at cardioversion were made for each waveform. Success was defined as reversion to sinus rhythm within 5 beats of shock delivery.
No arrhythmic complications were observed for the 400 shocks delivered.
A reduction in phase 2 voltage does not affect the efficacy of rectangular waveforms but does facilitate energy reduction. Asymmetric rectangular biphasic waveforms with phase 2 voltage at 50% of phase 1 are more efficacious than equivalent voltage conventional waveforms for transvenous cardioversion of AF. The novel defibrillator is safe and effective. Design modifications will enable this device to be used as an implantable defibrillator with an external RF power source.
我们研究了一种新型装置，该装置在经静脉房颤（AF）心脏复律中可提供无倾斜的双相和单相电击。该装置包含一个射频（RF）发射初级线圈、一个15毫米的气隙和一个产生所需直流波形的无源次级单元。
在10只麻醉并通气的绵羊（65±标准差12千克）中对该装置进行评估。除颤导线置于远端冠状窦和右心房外侧。使用矩形单相或双相脉冲对新型射频除颤器进行评估，并与传统（C）倾斜波形（Ventritex HVS - 02）进行比较。在房颤期间，向50Ω假负载施加安慰剂电击。通过快速心房起搏诱发持续性房颤，对每种波形进行5次心脏复律尝试。成功定义为电击后5个心动周期内恢复窦性心律。
在施加的400次电击过程中未观察到心律失常并发症。
第2相电压的降低不影响矩形波形的疗效，但有助于降低能量。对于经静脉房颤心脏复律，第2相电压为第1相电压50%的不对称矩形双相波形比等效电压的传统波形更有效。新型除颤器安全有效。设计改进将使该装置能够用作具有外部射频电源的植入式除颤器。
