A low-energy low-delay synchronized defibrillator for cardiac arrhythmias

Background and Objective

Excessive electric shock energy and inappropriate timing of electric shocks can lead to an increased incidence of myocardial cell damage and exacerbation of cardiac arrhythmias (CAs). This study introduces a novel synchronized defibrillator for CAs integrating an R-wave localization circuit and an impedance measurement circuit, aiming to lower the defibrillation energy and minimize the delay in synchronized shocks. To validate the effectiveness of the design, the synchronized shock delay time of this defibrillator was tested under conditions of atrial fibrillation (AF) and ventricular tachycardia (VT). Shock energy tests were performed under different impedance conditions in comparison of a commercialized synchronized defibrillator – BeneHeart D3. The results showed that under AF conditions, the novel device had a mean synchronized defibrillation delay time of 1.2 ms (SD = 1.8 ms), significantly lower than the BeneHeart D3′s mean delay of 29.6 ms (SD = 12.8 ms), and the standard deviation of delay time of the novel device was also significantly lower than that of the control group (p < 0.001). For VT, the synchronized defibrillation delay times were analyzed at heart rates of 160 and 200 bpm. At 160 bpm, the novel device showed a mean delay of 16.4 ms (SD = 3.3 ms) compared to 40.4 ms (SD = 12.5 ms) for the BeneHeart D3. At 200 bpm, the novel device demonstrated a mean delay of 16.5 ms (SD = 13.9 ms), significantly shorter than the 67.3 ms (SD = 18.2 ms) observed with the BeneHeart D3 (p < 0.001). The novel defibrillator showed comparable mean defibrillation energy with BeneHeart D3 for 50 Ω bioimpedance. However, the novel defibrillator presented 48 % and 65 % reductions in the mean defibrillation energy comparing with BeneHeart D3 for 100 Ω and 150 Ω bioimpedances, while maintaining therapeutic efficacy. An animal experiment was further performed on 15 pigs, showing that the novel defibrillator outperformed the BeneHeart D3 in the return of spontaneous circulation rate and 24-hour survival rate (p < 0.05).