As an important medical electronic equipment for the cardioversion of malignant arrhythmia such as ventricular fibrillation and ventricular tachycardia, cardiac external defibrillators have been widely used in the clinics. However, the resuscitation success rate for these patients is still unsatisfied. In this paper, the recent advances of cardiac external defibrillation technologies is reviewed. The potential mechanism of defibrillation, the development of novel defibrillation waveform, the factors that may affect defibrillation outcome, the interaction between defibrillation waveform and ventricular fibrillation waveform, and the individualized patient-specific external defibrillation protocol are analyzed and summarized. We hope that this review can provide helpful reference for the optimization of external defibrillator design and the individualization of clinical application.
Arrhythmias, Cardiac ; Defibrillators ; Heart ; Heart Arrest ; Humans ; Ventricular Fibrillation/therapy*

Defibrillator is an important first aid equipment with people attach importance to life and health in today, people pay more attention to the development of defibrillator. This paper reviews the development history of the defibrillator, gives a brief introduction to the structure and working principle of the defibrillator, and then analyzes the key technology of defibrillator, compares the mainstream products on the market and prospects the development trend of defibrillator.
Defibrillators ; Electric Countershock ; First Aid ; Humans ; Technology ; Ventricular Fibrillation ; therapy

Objective: This study aimed to examine the effects of microcirculatory dysfunction and 654-1 intervention after cardiopulmonary resuscitation on myocardial injury. Methods: Landrace pigs were divided into a sham operation group (S group, n= 6), ventricular fibrillation control group (VF-C group, n= 8) and 654-1 intervention group (VF-I group, n= 8). Hemodynamics was recorded at baseline, at recovery of spontaneous circulation (ROSC), and 1 h, 2 h, 4 h and 6 h thereafter. Sidestream dark field (SDF) technology was used to evaluate and monitor the microcirculation flow index, total vessel density, perfusion vessel ratio, De-Backer score, and perfusion vessel density in animal viscera at various time points. Results: After administration of 654-1 at 1.5 h post-ROSC, the hemodynamics in the VF-I group, as compared with the VF-C group, was significantly improved. The visceral microcirculation detected by SDF was also significantly improved in the VF-I group. As observed through electron microscopy, significantly less myocardial tissue injury was present in the VF-I group than the VF-C group. Conclusion Administration of 654-1 inhibited excessive inflammatory by improving the state of visceral microcirculation.
Animals ; Cardiopulmonary Resuscitation ; Microcirculation ; Swine ; Ventricular Fibrillation/therapy*

Electrical defibrillation is the most effective way to treat the ventricular tachycardia (VT) and ventricular fibrillation (VF). An automatic external defibrillator based on DSP is introduced in this paper. The whole design consists of the signal collection module, the microprocessor controlingl module, the display module, the defibrillation module and the automatic recognition algorithm for VF and non VF, etc. This automatic external defibrillator has achieved goals such as ECG signal real-time acquisition, ECG wave synchronous display, data delivering to U disk and automatic defibrillate when shockable rhythm appears, etc.
Algorithms ; Defibrillators ; Equipment Design ; Humans ; Tachycardia, Ventricular ; therapy ; Ventricular Fibrillation ; therapy

BACKGROUNDCardiac resynchronization therapy (CRT) could improve heart function, symptom status, quality of life and reduce hospitalization and mortality in patients with severe heart failure (HF) with optimal medical management. However, the possible adverse effects of CRT are often ignored by clinicians.

METHODA retrospective analysis of CRT over a 6-year period was made in a single cardiac center.

RESULTSFifty-four patients were treated with CRT(D) device, aged (57 ± 11) years, with left ventricular ejection fraction of (32.1 ± 9.8)%, of which 4 (7%) developed ventricular tachycardia/ventricular fibrillation (VT/VF) or junctional tachycardia after operation. Except for one with frequent ventricular premature beat before operation, the others had no previous history of ventricular arrhythmia. Of the 4 patients, 3 had dilated cardiomyopathy and 1 had ischemic cardiomyopathy, and tachycardia occurred within 3 days after operation. Sustained, refractory VT and subsequent VF occurred in one patient, frequent nonsustained VT in two patients and nonparoxysmal atrioventricular junctional tachycardia in one patient. VT was managed by amiodarone in two patients, amiodarone together with beta-blocker in one patient, and junctional tachycardia was terminated by overdrive pacing. During over 12-month follow-up, except for one patient's death due to refractory heart and respiratory failure in hospital, the others remain alive and arrhythmia-free.

CONCLUSIONSNew-onset VT/VF or junctional tachycardia may occur in a minority of patients with or without prior history of tachycardia after biventricular pacing. Arrhythmia can be managed by conventional therapy, but may require temporary discontinuation of pacing. More observational studies should be performed to determine the potential proarrhythmic effect of CRT.

BACKGROUNDThe choice of a defibrillation or a cardiopulmonary resuscitation (CPR)-first strategy in the treatment of prolonged cardiac arrest (CA) is still controversial. The purpose of this study was to compare the effects of defibrillation or CPR administered first on neurological prognostic markers in a porcine model of prolonged CA.

METHODSAfter 8 minutes of untreated ventricular fibrillation (VF), 24 inbred Chinese Wuzhishan minipigs were randomized to receive either defibrillation first (ID group, n = 12) or chest compression first (IC group, n = 12). In the ID group, a shock was delivered immediately. If defibrillation failed to attain restoration of spontaneous circulation (ROSC), manual chest compressions were rapidly initiated at a rate of 100 compressions/min and a compression-to-ventilation ratio of 30:2. If VF persisted after five cycles of CPR, a second defibrillation attempt was made. In the IC group, chest compressions were delivered first, followed by a shock. After successful ROSC, hemodynamic status and blood samples were obtained at 0.5, 1, 2, 4, 6, and 24 hours after ROSC. Porcine-specific neuron-specific enolase (NSE) and S100B were measured from sera using enzyme-linked immunosorbent assays. Porcine cerebral performance category scores were used to evaluate preliminary neurological function following 24 hours recovery. Surviving pigs were sacrificed at 24 hours after ROSC and brains were removed for electron microscopy analysis.

RESULTSThe number of shocks, total defibrillation energy, and time to ROSC were significantly lower in the ID group compared with the IC group. Compared with the IC group, S100B expression was decreased at 2 and 4 hours after ROSC, and NSE expression decreased at 6 and 24 hours after ROSC in the ID group. Brain tissue analysis showed that injury was attenuated in the ID group compared with the IC group. There were no significant differences between 6 and 24 hours survival rates.

CONCLUSIONDefibrillation first may result in a shorter time to ROSC and lower biochemical markers of brain injury in a porcine model of 8-minute CA due to VF, but the choice of different resuscitation strategies did not affect the rate of ROSC and 24-hour survival.

Defibrillation is the most effective method of treating ventricular fibrillation(VF), this paper introduces wearable automatic external defibrillators based on embedded system which includes EGG measurements, bioelectrical impedance measurement, discharge defibrillation module, which can automatic identify VF signal, biphasic exponential waveform defibrillation discharge. After verified by animal tests, the device can realize EGG acquisition and automatic identification. After identifying the ventricular fibrillation signal, it can automatic defibrillate to abort ventricular fibrillation and to realize the cardiac electrical cardioversion.
Animals ; Defibrillators ; Electric Countershock ; Electric Impedance ; Equipment Design ; Heart ; Humans ; Monitoring, Physiologic ; instrumentation ; Ventricular Fibrillation ; therapy

OBJECTIVEThe aim of this study was to evaluate the recognition and defibrillation efficiency of a newly developed automated external defibrillator (AED).

METHODVentricular tachycardia (VT)/ventricular fibrillation (VF) was induced by alternating current (50 Hz) through an electrode placed on apex of right ventricle in 23 anesthetized swine and recorded, recognized and defibrillated by a newly developed AED.

RESULTSA total of 96 VF was induced and 145 defibrillations were recorded. We analyzed available 167 electrocardiosignal with a total length of 103,740 seconds. The accuracy, sensitivity and the specificity of the AED on VT/VF recognition are 99.5%, 98.2% and 99.6%, respectively. The success rate of defibrillation was 33.4% which increased in proportion to defibrillation energy. The defibrillation threshold of energy is 29.10-116.91 (78.75 +/- 35.64) J, the defibrillation threshold of electric quantity is (0.11 +/- 0.04) C and the defibrillation threshold of voltage is (1216.67 +/- 260.87) V.

CONCLUSIONSThis newly developed AED has high sensitivity and the specificity on recognizing VT/VF. The lower success rate of defibrillation of this AED is associated with the low defibrillation energy during defibrillation which needs to be improved on further development.

Female ; Humans ; Middle Aged ; Propofol ; therapeutic use ; Pulmonary Embolism ; complications ; Ventricular Fibrillation ; drug therapy ; etiology

Described here is the progress of the electrical treatment for arrhythmia during the past half a century. The mechanism, their expression and the principles of electrical treatment for bradycardia, tachycardia and fatal arrhythmia--ventricular fibrillation (VF) are introduced respectively. The current situation and future development of the pacemaker, RF ablation and implantable cardioversion defibrillator are also discussed in the paper.
Arrhythmias, Cardiac ; surgery ; therapy ; Bradycardia ; therapy ; Cardiac Pacing, Artificial ; classification ; trends ; Catheter Ablation ; trends ; Defibrillators, Implantable ; classification ; trends ; Humans ; Tachycardia, Ventricular ; therapy ; Ventricular Fibrillation ; therapy