Appropriate use of wearable defibrillators with multiparametric evaluation to avoid unnecessary defibrillator implantation.

INTRODUCTION: Wearable cardioverter-defibrillators (WCD) have emerged as a valuable tool in the management of patients at risk for life-threatening arrhythmias. These devices offer a non-invasive and temporary solution, providing continuous monitoring and the potential for prompt defibrillation when needed. In this study, we explore the use of WCD and evaluate arrhythmic events through comprehensive monitoring. METHODS: From November 2022 to May 2024, we conducted an outpatient follow-up of 41 patients receiving WCD. Regular check-ups, remote monitoring and comprehensive echocardiography were performed to optimise a tailored therapy. RESULTS: The average age of the patients was 59.2.4±16.5 years, with 78% being male. Among the cohort, 54% had hypertension, 41% were smokers and 66% had dyslipidaemia, while 27% were diabetic. WCD was assigned according to the Italian Association of Hospital Cardiologists position paper focussing on the appropriate use of WCD and European Society of Cardiology guidelines on ventricular arrhythmias and the prevention of sudden cardiac death: 24 (58%) patients had a de novo diagnosis of heart failure with reduced ejection fraction, 11 (27%) patients had a recent acute coronary syndrome and ejection fraction <35%, 3 (7%) patients had a cardiac electronic device extraction and 3 (7%) patients had myocarditis with features of electrical instability. The average follow-up was 62±38 days according to specific aetiology, with a daily wearing time of 22.7±1.3 hours. No device interventions were recorded. At the end of the follow-up period, 15 patients still required an implantable cardioverter-defibrillator (ICD). Among these, 12 patients (29%) underwent ICD implantation. Two patients (5%) declined the procedure. CONCLUSIONS: The use of WCD for patients at high risk of arrhythmias allowed to optimise therapy and limit the indications for ICD. Inappropriate implantation of ICD was avoided in 69% of patients who received WCD. The device showed a good safety profile, low incidence of device interventions and adequate patients' adherence to WCD use.

Training experience is an important factor affecting willingness for bystander CPR and awareness of AED: a survey of residents from a province in Central China in 2023.

Background: Bystander cardiopulmonary resuscitation (CPR) and the use of automated external defibrillators (AEDs) may improve survival in patients with out-of-hospital cardiac arrest (OHCA). The purpose of this study was to investigate the effect of CPR training experience and sociodemographic characteristics on bystander CPR willingness and AED awareness. Methods: In this study, a questionnaire survey was conducted among 3,569 residents in central China. Descriptive statistics, multiple linear regression and multivariate logistic regression modeling were used to investigate the effect of training experience and sociodemographic characteristics on knowledge of cardiac arrest first aid, awareness of AEDs, and willingness for bystander CPR. Results: Of the 3,569 participants, nearly 52% were female, 69.6% were < 23 years old, 23.5% had CPR training and 22.1% had witnessed OHCA. Characteristics of increasing bystander CPR willingness included CPR training experience, male, witnessed OHCA but not acting, knowing whether family members have cardiac disease, older age (>40 years) and lower level of education. Farmers were the subgroup with the least awareness of AED and knowledge of first aid. Conclusion: In China, CPR training experience was an important factor in improving bystanders' CPR willingness, AED awareness and knowledge of cardiac arrest first aid. Additionally, having witnessed OHCA also had a positive effect on bystander CPR willingness.

Association between bystander automated external defibrillator use and survival in witnessed out-of-hospital cardiac arrest: A nationwide observational study in South Korea.

AIM: Sudden cardiac arrest is a global health issue, with out-of-hospital cardiac arrest (OHCA) posing a major challenge. Bystander cardiopulmonary resuscitation (CPR) and automated external defibrillators (AEDs) improve survival and neurological outcomes. However, their actual usage involves numerous constraints. Therefore, to determine the association between bystander AED use and survival of patients with OHCA, we analyzed South Korea's national OHCA database. METHODS: This retrospective study included cases from the Korea Disease Control and Prevention Agency's Out-of-Hospital Cardiac Arrest Surveillance database from January 2016 to December 2021. Adult OHCA cases treated with bystander intervention were categorized into two groups, CPR with AEDs and without AEDs. Propensity score matching was employed to control for confounders and analyze bystander AED use's impact on survival to discharge and neurological outcomes. RESULTS: Of 182,508 OHCA cases, 35,840 met the inclusion criteria, with 234 (0.7%) receiving bystander CPR with AEDs. The survival rate to discharge in the AED and non-AED group was 46.6% and 23.0%, respectively. However, after adjusting for potential confounders, bystander AED use did not significantly affect survival to discharge (adjusted odds ratio [aOR] 1.01, 95% confidence interval [CI] 0.70-1.44) or favorable neurological outcomes (aOR 1.08, 95% CI 0.99-1.18). CONCLUSION: Survival to discharge or favorable neurological outcomes of patients with OHCA managed using bystander-applied AEDs and those without showed no significant difference. Factors such as AED accessibility and bystander preparedness influence the impact of bystander AED use. Further research should optimize AED deployment and usage strategies to enhance patient survival rate.

The factors associated with the provision of public access defibrillation in Japan - A nationwide cohort study.

AIM: The association between out-of-hospital cardiac arrest (OHCA) and the appropriate provision of public access defibrillation (PAD) remains unclear. This study aimed to evaluate the factors associated with whether or not PAD was provided. METHODS: This retrospective cohort study utilized the All-Japan Utstein and Emergency Transport Registries in 2021. We included OHCA patients who were applied to automated external defibrillators (AEDs) by bystanders and were deemed eligible for defibrillation by an AED. We defined PAD provided or no PAD provided based on bystander defibrillation. Multivariable logistic regression analysis with the Firth bias adjustment method was employed to estimate the adjusted odds ratios (AORs) and 95% confidence intervals (CIs) for the exploratory evaluation of factors associated with PAD provided. RESULTS: 1949 patients were eligible for analysis (PAD provided, n = 1696 [87.0%]; no PAD provided, n = 253 [13.0%]). Factors positively associated with PAD provided were male (AOR [95% CI], 1.61 [1.17-2.21]; vs. female), other public place incidence (AOR [95% CI], 10.65 [1.40-1367.54]; vs. public place), non-family member witnessed (AOR [95% CI], 2.51 [1.86-3.42]; vs. unwitnessed) and conventional cardiopulmonary resuscitation (CPR), (AOR [95% CI], 1.75 [1.17-2.67]; vs. hands-only CPR). Conversely, factors negatively associated with no PAD provided were over 65 years old (AOR [95% CI], 0.48 [0.28-0.80]; vs. 19-64 yr), night-time onset (AOR [95% CI], 0.61 [0.45-0.83]; vs. daytime), non-cardiogenic (AOR [95% CI], 0.43 [0.31-0.61]; vs. cardiogenic), home setting (AOR [95% CI], 0.33 [0.14-0.83]; vs. public place), healthcare facility setting (AOR [95% CI], 0.40 [0.23-0.66]; vs. public place), no bystander CPR (AOR [95% CI], 0.31 [0.14-0.71]; vs. hands-only CPR), and dispatcher-assistance (AOR [95% CI], 0.72 [0.53-0.97]; vs. no dispatcher-assistance). CONCLUSION: Male patients, other public place onset, witnessed by non-family and conventional CPR were associated with PAD provide. Therefore, training skilled first responders to use AEDs appropriately is necessary.

Initial Defibrillator Pad Position and Outcomes for Shockable Out-of-Hospital Cardiac Arrest.

Importance: Ventricular fibrillation (VF) or pulseless ventricular tachycardia (pVT) are the most treatable causes of out-of-hospital cardiac arrest (OHCA). Yet, it remains unknown if defibrillator pad position, placement in the anterior-posterior (AP) or anterior-lateral (AL) locations, impacts patient outcomes in VF or pVT OHCA. Objective: To determine the association between initial defibrillator pad placement position and OHCA outcomes for patients presenting with VF or pVT. Design, Setting, and Participants: This prospective cohort study included patients with OHCA and VF or pVT treated by a single North American emergency medical services (EMS) agency from July 1, 2019, through June 30, 2023. The study included patients with OHCA treated by a large suburban fire-based EMS agency that covers a population of 550 000. Consecutive patients with an initial EMS-assessed rhythm of VF or pVT receiving EMS defibrillation were included. Pediatric patients (younger than 18 years), interfacility transfers, arrests of obvious traumatic etiology, and patients with preexisting do-not-resuscitate status were excluded. Exposure: AP or AL pad placement. Main Outcomes and Measures: Return of spontaneous circulation (ROSC) at any time with secondary outcomes of pulses present at emergency department (ED) arrival, survival to hospital admission, survival to hospital discharge, and functional survival at hospital discharge (cerebral performance category score of 2 or less). Measures included adjusted odds ratios (aOR), multivariable logistic regressions, and Fine-Gray competing risks regression. Results: A total of 255 patients with OHCA were included (median [IQR] age, 66 [55-74] years; 63 females [24.7%]), with initial pad positioning documented as either AP (158 patients [62.0%]; median [IQR] age, 65 [54-74] years; 37 females [23.4%]) or AL (97 patients [38.0%]; median [IQR] age, 66 [57-74] years; 26 females [26.8%]). Patients with AP placement had higher adjusted odds ratio (aOR) of ROSC at any time (aOR, 2.64 [95% CI, 1.50-4.65]), but not significantly different odds of pulses present at ED arrival (1.34 [95% CI, 0.78-2.30]), survival to hospital admission (1.41 [0.82-2.43]), survival to hospital discharge (1.55 [95% CI, 0.83-2.90]), or functional survival at hospital discharge (1.86 [95% CI, 0.98-3.51]). Competing risk analysis found significantly greater cumulative incidence of ROSC among those at risk with initial AP placement compared with AL (subdistribution hazard ratio, 1.81 [95% CI, 1.23-2.67]; P = .003). Conclusions and Relevance: In this cohort study of patients with OHCA and VF or pVT, AP defibrillator pad placement was associated with higher ROSC compared with AL placement.

Comparison of Effectiveness of Two Different Practical Approaches to Teaching Basic Life Support and Use of an Automated External Defibrillator in Primary School Children.

Background and Objectives: As the first three links of the chain of survival of victims of cardiac arrest depend on prompt action by bystanders, it is important to educate as much of the population as possible about basic life support and use of an automatic external defibrillator (BLS and AED). Schoolchildren are an accessible population that can be easily taught and numerous BLS and AED courses are available. The aim of this study was to assess the effectiveness of two different practical approaches to teaching BLS and AED. Material and Methods: We compared two different BLS and AED courses (course A and B) offered to 280 eighth- and ninth-grade students in primary schools. Knowledge about and the intention to perform BLS and AED were evaluated using validated questionnaires before and after the courses. Descriptive methods were used to describe the results. To compare courses, we used the Mann-Whitney U test. A p value of <0.05 was considered statistically significant. Results: Differences in knowledge and intention to perform BLS and AED after the courses were significant between courses (p < 0.001 and p = 0.037, respectively). After course A, students demonstrated significantly better knowledge and numerically greater intention to perform BLS and AED (intention score 6.55 ± 0.61 out of 7). Conclusions: Courses in which students have the opportunity to individually practice BLS skills show a greater increase in knowledge and in intention to perform BLS and AED.

Dispatcher nurses' experiences of handling drones equipped with automated external defibrillators in suspected out-of-hospital cardiac arrest - a qualitative study.

BACKGROUND: Reducing the time to treatment by means of cardiopulmonary resuscitation (CPR) and defibrillation is essential to increasing survival after cardiac arrest. A novel method of dispatching drones for delivery of automated external defibrillators (AEDs) to the site of a suspected out-of-hospital cardiac arrest (OHCA) has been shown to be feasible, with the potential to shorten response times compared with the emergency medical services. However, little is known of dispatchers' experiences of using this novel methodology. METHODS: A qualitative semi-structured interview study with a phenomenological approach was used. Ten registered nurses employed at an emergency medical dispatch centre in Gothenburg, Sweden, were interviewed and the data was analysed by qualitative content analysis. The purpose was to explore dispatcher nurses' experiences of deliveries of AEDs by drones in cases of suspected OHCA. RESULTS: Three categories were formed. Nurses expressed varying compliance to the telephone-assisted protocol for dispatch of AED-equipped drones. They experienced uncertainty as to how long would be an acceptable interruption from the CPR protocol in order to retrieve a drone-delivered AED. The majority experienced that collegial support was important. Technical support, routines and training need to be improved to further optimise action in cases of drone-delivered AEDs handled by dispatcher nurses. CONCLUSIONS: Although telephone-assisted routines for drone dispatch in cases of OHCA were available, their use was rare. Registered nurses showed variable degrees of understanding of how to comply with these protocols. Collegial and technical support was considered important, alongside routines and training, which need to be improved to further support bystander use of drone-delivered AEDs. As the possibilities of using drones to deliver AEDs in cases of OHCA are explored more extensively globally, there is a good possibility that this study could be of benefit to other nations implementing similar methods. We present concrete aspects that are important to take into consideration when implementing this kind of methodology at dispatch centres.

The First Use of a Defibrillator on a U.S. Commercial Airline.

Use of onboard commercial airline defibrillators began in 1997. At first, it was met with resistance but is now present on all planes. The first in-flight resuscitation of a passenger occurred in 1998 and is described here.

A Deep-Learning-Based CPR Action Standardization Method.

In emergency situations, ensuring standardized cardiopulmonary resuscitation (CPR) actions is crucial. However, current automated external defibrillators (AEDs) lack methods to determine whether CPR actions are performed correctly, leading to inconsistent CPR quality. To address this issue, we introduce a novel method called deep-learning-based CPR action standardization (DLCAS). This method involves three parts. First, it detects correct posture using OpenPose to recognize skeletal points. Second, it identifies a marker wristband with our CPR-Detection algorithm and measures compression depth, count, and frequency using a depth algorithm. Finally, we optimize the algorithm for edge devices to enhance real-time processing speed. Extensive experiments on our custom dataset have shown that the CPR-Detection algorithm achieves a mAP0.5 of 97.04%, while reducing parameters to 0.20 M and FLOPs to 132.15 K. In a complete CPR operation procedure, the depth measurement solution achieves an accuracy of 90% with a margin of error less than 1 cm, while the count and frequency measurements achieve 98% accuracy with a margin of error less than two counts. Our method meets the real-time requirements in medical scenarios, and the processing speed on edge devices has increased from 8 fps to 25 fps.

Drones can be used to provide dispatch centres with on-site photos before arrival of EMS in time critical incidents.

BACKGROUND: Drones are able to deliver automated external defibrillators in cases of out-of-hospital cardiac arrest (OHCA) but can be deployed for other purposes. Our aim was to evaluate the feasibility of sending live photos to dispatch centres before arrival of other units during time-critical incidents. METHODS: In this retrospective observational study, the regional dispatch centre implemented a new service using five existing AED-drone systems covering an estimated 200000 inhabitants in Sweden. Drones were deployed automatically over a 4-month study period (December 2022-April 2023) in emergency calls involving suspected OHCAs, traffic accidents and fires in buildings. Upon arrival at the scene, an overhead photo was taken and transmitted to the dispatch centre. Feasibility of providing photos in real time, and time delays intervals were examined. RESULTS: Overall, drones were deployed in 59/440 (13%) of all emergency calls: 26/59 (44%) of suspected OHCAs, 20/59 (34%) of traffic accidents, and 13/59 (22%) of fires in buildings. The main reasons for non-deployment were closed airspace and unfavourable weather conditions (68%). Drones arrived safely at the exact location in 58/59 cases (98%). Their overall median response time was 3:49 min, (IQR 3:18-4:26) vs. emergency medical services (EMS), 05:51 (IQR: 04:29-08:04) p-value for time difference between drone and EMS = 0,05. Drones arrived first on scene in 47/52 cases (90%) and the largest median time difference was found in suspected OHCAs 4:10 min, (IQR: 02:57-05:28). The time difference in the 5/52 (10%) cases when EMS arrived first the time difference was 5:18 min (IQR 2:19-7:38), p = NA. Photos were transmitted correctly in all 59 alerts. No adverse events occurred. CONCLUSION: In a newly implemented drone dispatch service, drones were dispatched to 13% of relevant EMS calls. When drones were dispatched, they arrived at scene earlier than EMS services in 90% of cases. Drones were able to relay photos to the dispatch centre in all cases. Although severely affected by closed airspace and weather conditions, this novel method may facilitate additional decision-making information during time-critical incidents.

RAndomized Cluster Evaluation of Cardiac ARrest Systems (RACE-CARS) trial: Study rationale and design.

Out-of-hospital cardiac arrest (OHCA) occurs in nearly 350,000 people each year in the United States (US). Despite advances in pre and in-hospital care, OHCA survival remains low and is highly variable across systems and regions. The critical barrier to improving cardiac arrest outcomes is not a lack of knowledge about effective interventions, but rather the widespread lack of systems of care to deliver interventions known to be successful. The RAndomized Cluster Evaluation of Cardiac ARrest Systems (RACE-CARS) trial is a 7-year pragmatic, cluster-randomized trial of 62 counties (57 clusters) in North Carolina using an established registry and is testing whether implementation of a customized set of strategically targeted community-based interventions improves survival to hospital discharge with good neurologic function in OHCA relative to control/standard care. The multifaceted intervention comprises rapid cardiac arrest recognition and systematic bystander CPR instructions by 9-1-1 telecommunicators, comprehensive community CPR training and enhanced early automated external defibrillator (AED) use prior to emergency medical systems (EMS) arrival. Approximately 20,000 patients are expected to be enrolled in the RACE CARS Trial over 4 years of the assessment period. The primary endpoint is survival to hospital discharge with good neurologic outcome defined as a cerebral performance category (CPC) of 1 or 2. Secondary outcomes include the rate of bystander CPR, defibrillation prior to arrival of EMS, and quality of life. We aim to identify successful community- and systems-based strategies to improve outcomes of OHCA using a cluster randomized-controlled trial design that aims to provide a high level of evidence for future application.

A Patch Wearable Cardioverter-Defibrillator for Patients at Risk of Sudden Cardiac Arrest.

BACKGROUND: For many patients, sudden cardiac arrest (SCA) risk is elevated temporarily. Wearable cardioverter-defibrillators (WCDs) can monitor and treat SCA during these temporary periods. Traditional WCDs can be uncomfortable, require frequent maintenance, and cannot be used when showering, resulting in poor compliance and avoidable SCA deaths. The Jewel is a novel, water-resistant patch-wearable cardioverter-defibrillator (P-WCD) with a machine learning detection algorithm designed to improve compliance and protection against SCA. OBJECTIVES: This study aims to demonstrate the safety and clinical effectiveness of a novel P-WCD. METHODS: The Jewel IDE Study, a prospective, single-arm study conducted at 30 U.S. sites, enrolled patients at SCA risk due to ventricular tachycardia/ventricular fibrillation who were not candidates for or refused an implantable defibrillator. The primary safety endpoint was <15% patients with clinically significant cutaneous adverse device effects and the primary effectiveness endpoint was <2 inappropriate shocks/100 patient-months. Secondary endpoints were ≥1 successful ventricular tachycardia/ventricular fibrillation conversion and wear time compliance of >14.1 h/d. RESULTS: A total of 305 patients (mean age: 57.9 years; 30.2% female, 27.9% non-White) were enrolled, of which 290 had available device data. The clinically significant cutaneous adverse device effect rate was 2.30% (upper 1-sided 98% CI: 4.80); none were severe. No device-related deaths or serious adverse events were reported. The inappropriate shock rate was 0.36/100 patient-months (upper 1-sided 98% CI: 1.53). Of 11 shocks in 9 patients, 9 shocks were adjudicated to be appropriate. Eight of 9 shocks were successful with a single shock. Median wear time compliance was 23.5 (20.7-23.9) h/d. CONCLUSIONS: The novel P-WCD is a safe and effective WCD with high patient compliance. There were no deaths due to noncompliance and a high number of successful conversions (Jewel IDE study [A Clinical Evaluation of the Jewel P-WCD in Subjects at High Risk for Sudden Cardiac Arrest]; NCT05201495).

First human safety and effectiveness study of defibrillation with a novel patch wearable cardioverter-defibrillator.

AIMS: Wearable cardioverter-defibrillators (WCDs) are indicated in patients at risk of sudden cardiac arrest who are not immediate candidates for implantable defibrillator therapy. Limitations of existing WCDs include poor compliance and high false alarm rates. The Jewel is a novel patch-WCD (P-WCD) that addresses these limitations with an adhesive-based design for near-continuous wear and a machine learning algorithm designed to minimize inappropriate detections. This was a first-in-human study of the Jewel P-WCD conducted in an electrophysiology (EP) lab to determine the safety and effectiveness of the device in terminating ventricular tachycardia/ventricular fibrillation (VT/VF) with a single shock. The aim was to evaluate the safety and effectiveness of terminating VT/VF with a single shock using the Jewel P-WCD. METHODS AND RESULTS: This was a first-in-human, prospective, single-arm, single-centre study in patients scheduled for an EP procedure in which VT/VF was expected to either spontaneously occur or be induced. The Jewel P-WCD was placed on consented patients; upon confirmation of VT/VF, a single shock (150 J) was delivered via the device. A group sequential design and Pocock alpha spending function was used to measure the observed proportion of successful VT/VF single-shock terminations. The endpoint was achieved if the lower confidence limit exceeded the performance goal of 62%, using a one-sided lower 97.4% exact confidence bound. Of 18 eligible subjects, 16 (88.9%, 97.4% confidence bound: 65.4%) were successfully defibrillated with a single shock, exceeding the primary endpoint performance goal with no adverse events. CONCLUSION: This first-in-human evaluation of the Jewel P-WCD demonstrated the safety and effectiveness of terminating VT/VF. CLINICAL TRIAL REGISTRATION: URL: https://clinicaltrials.gov/; Unique identifier: NCT05490459.

Increasing cost-effectiveness of AEDs using algorithms to optimise location.

OBJECTIVES: Volunteer responder systems (VRSs) aim to decrease time to defibrillation by dispatching trained volunteers to automated external defibrillators (AEDs) and out-of-hospital cardiac arrest (OHCA) victims. AEDs are often underutilized due to poor placement. This study provides a cost-effectiveness analysis of adding AEDs at strategic locations to maximize quality-adjusted life years (QALYs). METHODS: We simulated combined volunteer, police, firefighter, and emergency medical service response scenarios to OHCAs, and applied our methods to a case study of Amsterdam, the Netherlands. We compared the competing strategies of placing additional AEDs, using steps of 40 extra AEDs (0, 40, …, 1480), in addition to the existing 369 AEDs. Incremental cost-effectiveness ratios (ICERs) were calculated for each increase in additional AEDs, from a societal perspective. The effect of AED connection and time to connection on survival to hospital admission and neurological outcome at discharge was estimated using logistic regression, using OHCA data from Amsterdam from 2006 to 2018. Other model inputs were obtained from literature. RESULTS: Purchasing up to 1120 additional AEDs (ICER €75,669/QALY) was cost-effective at a willingness-to-pay threshold of €80,000/QALY, when positioned strategically. Compared to current practice, adding 1120 AEDs resulted in a gain of 0.111 QALYs (95% CI 0.110-0.112) at an increased cost of €3792 per OHCA (95% CI €3778-€3807). Health benefits per AED diminished as more AEDs were added. CONCLUSIONS: Our study identified cost-effective strategies to position AEDs at strategic locations in a VRS. The case study findings advocate for a substantial increase in the number of AEDs in Amsterdam.

Analysis during chest compressions in out-of-hospital cardiac arrest patients, a cross/sectional study: The DEFI 2022 study.

AIMS: During out-of-hospital cardiac arrest (OHCA), an automatic external defibrillator (AED) analyzes the cardiac rhythm every two minutes; however, 80% of refibrillations occur within the first minute post-shock. We have implemented an algorithm for Analyzing cardiac rhythm While performing chest Compression (AWC). When AWC detects a shockable rhythm, it shortens the time between analyses to one minute. We investigated the effect of AWC on cardiopulmonary resuscitation quality. METHOD: In this cross-sectional study, we compared patients treated in 2022 with AWC, to a historical cohort from 2017. Inclusion criteria were OHCA patients with a shockable rhythm at the first analysis. Primary endpoint was the chest compression fraction (CCF). Secondary endpoints were cardiac rhythm evolution and survival, including survival analysis of non-prespecified subgroups. RESULTS: In 2017 and 2022, 355 and 377 OHCAs met the inclusion criteria, from which we analyzed the 285 first consecutive cases in each cohort. CCF increased in 2022 compared to 2017 (77% [72-80] vs 72% [67-76]; P < 0.001) and VF recurrences were shocked more promptly (53 s [32-69] vs 117 s [90-132]). Survival did not differ between 2017 and 2022 (adjusted hazard-ratio 0.96 [95% CI, 0.78-1.18]), but was higher in 2022 within the sub-group of OHCAs that occurred in a public place and within a short time from call to AED switch-on (adjusted hazard ratio 0.85[0.76-0.96]). CONCLUSIONS: OHCA patients treated with AWC had higher CCF, shorter time spent in ventricular fibrillation, but no survival difference, except for OHCA that occurred in public places with short intervention time.