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Background: In the last decade, there has been a rapid increase in the dissemination of automated external defibrillators (AEDs) for prehospital defibrillation of out-of-hospital cardiac arrest patients. The aim of this study was to study the association between different defibrillation strategies on survival rates over time in Copenhagen, Stockholm, Western Sweden and Amsterdam, and the hypothesis was that non-EMS defibrillation increased over time and was associated with increased survival., Methods: We performed a retrospective analysis of four prospectively collected cohorts of out-of-hospital cardiac arrest patients between 2008 and 2013. Emergency medical service (EMS)-witnessed arrests were excluded., Results: A total of 22 453 out-of-hospital cardiac arrest patients with known survival status were identified, of whom 2957 (13%) survived at least 30 days postresuscitation. Of all survivors with a known defibrillation status, 2289 (81%) were defibrillated, 1349 (59%) were defibrillated by EMS, 454 (20%) were defibrillated by a first responder AED and 429 (19%) were defibrillated by an onsite AED and 57 (2%) were unknown. The percentage of survivors defibrillated by first responder AEDs (from 13% in 2008 to 26% in 2013, p<0.001 for trend) and onsite AEDs (from 14% in 2008 to 30% in 2013, p<0.001 for trend) increased. The increased use of these non-EMS AEDs was associated with the increase in survival rate of patients with a shockable initial rhythm., Conclusion: Survivors of out-of-hospital cardiac arrest are increasingly defibrillated by non-EMS AEDs. This increase is primarily due to a large increase in the use of onsite AEDs as well as an increase in first-responder defibrillation over time. Non-EMS defibrillation accounted for at least part of the increase in survival rate of patients with a shockable initial rhythm., Competing Interests: Competing interests: None declared., (© Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2018. All rights reserved. No commercial use is permitted unless otherwise expressly granted.)

Background: The highest achievable survival rate following out-of-hospital cardiac arrest is unknown. Data from airports serving international destinations (international airports) provide the opportunity to evaluate the success of pre-hospital resuscitation in a relatively controlled but real-life environment., Methods: This retrospective cohort study included all cases of out-of-hospital cardiac arrest at international airports with resuscitation attempted between January 1st, 2013 and December 31st, 2015. Crude incidence, patient, event characteristics and survival to hospital discharge/survival to 30 days (survival) were calculated. Mixed effect logistic regression analyses were performed to identify predictors of survival. Variability in survival between airports/countries was quantified using the median odds ratio., Results: There were 800 cases identified, with an average of 40 per airport. Incidence was 0.024/100,000 passengers per year. Percentage survival for all patients was 32%, and 58% for patients with an initial shockable heart rhythm. In adjusted analyses, initial shockable heart rhythm was the strongest predictor of survival (odds ratio, 36.7; 95% confidence interval [CI], 15.5-87.0). In the bystander-witnessed subgroup, delivery of a defibrillation shock by a bystander was a strong predictor of survival (odds ratio 4.8; 95% CI, 3.0-7.8). Grouping of cases was significant at country level and survival varied between countries., Conclusions: In international airports, 32% of patients survived an out-of-hospital cardiac arrest, substantially more than in the general population. Our analysis suggested similarity between airports within countries, but differences between countries. Systematic data collection and reporting are essential to ensure international airports continually maximise activities to increase survival., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Out-of-hospital cardiac arrest (OHCA) is a major health problem that affects approximately four hundred and thousand patients annually in the United States alone. It is a major challenge for the emergency medical system as decreased survival rates are directly proportional to the time delay from collapse to defibrillation. Historically, defibrillation has only been performed by physicians and in-hospital. With the development of automated external defibrillators (AEDs), rapid defibrillation by nonmedical professionals and subsequently by trained or untrained lay bystanders has become possible. Much hope has been put to the concept of Public Access Defibrillation with a massive dissemination of public available AEDs throughout most Western countries. Accordingly, current guidelines recommend that AEDs should be deployed in places with a high likelihood of OHCA. Despite these efforts, AED use is in most settings anecdotal with little effect on overall OHCA survival. The major reasons for low use of public AEDs are that most OHCAs take place outside high incidence sites of cardiac arrest and that most OHCAs take place in residential settings, currently defined as not suitable for Public Access Defibrillation. However, the use of new technology for identification and recruitment of lay bystanders and nearby AEDs to the scene of the cardiac arrest as well as new methods for strategic AED placement redefines and challenges the current concept and definitions of Public Access Defibrillation. Existing evidence of Public Access Defibrillation and knowledge gaps and future directions to improve outcomes for OHCA are discussed. In addition, a new definition of the different levels of Public Access Defibrillation is offered as well as new strategies for increasing AED use in the society., (© 2018 The Association for the Publication of the Journal of Internal Medicine.)

Aim: An increasing number of failing automated external defibrillators (AEDs) is reported: AEDs not giving a shock or other malfunction. We assessed to what extent AEDs are 'failing' and whether this had a device-related or operator-related cause., Methods: We studied analysis periods from AEDs used between January 2012 and December 2014. For each analysis period we assessed the correctness of the (no)-shock advice (sensitivity/specificity) and reasons for an incorrect (no)-shock advice. If no shock was delivered after a shock advice, we assessed the reason for no-shock delivery., Results: We analyzed 1114 AED recordings with 3310 analysis periods (1091 shock advices; 2219 no-shock advices). Sensitivity for coarse ventricular fibrillation was 99% and specificity for non-shockable rhythm detection 98%. The AED gave an incorrect shock advice in 4% (44/1091) of all shock advices, due to device-related (n=15) and operator-related errors (n=28) (one unknown). Of these 44 shock advices, only 2 shocks caused a rhythm change. One percent (26/2219) of all no-shock advices was incorrect due to device-related (n=20) and operator-related errors (n=6). In 5% (59/1091) of all shock advices, no shock was delivered: operator failed to deliver shock (n=33), AED was removed (n=17), operator pushed 'off' button (n=8) and other (n=1). Of the 1073 analysis periods with a shockable rhythm, 67 (6%) did not receive an AED shock., Conclusion: Errors associated with AED use are rare (4%) and when occurring are in 72% caused by the operator or circumstances of use. Fully automatic AEDs may prevent the majority of these errors., (Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.)

Background: Previous large retrospective analyses have found an association between duration of peri-shock pauses in cardiopulmonary resuscitation (CPR) and survival. In a randomized trial, we tested whether shortening these pauses improves survival after out-of-hospital cardiac arrest (OHCA)., Methods: Patients with OHCA between May 2006 and January 2014 with shockable initial rhythm, treated by first responders, were randomized to two automated external defibrillator (AED) treatment protocols. In the control protocol AEDs performed post-shock analysis and prompted rescuers to a pulse check (Guidelines 2000). In the experimental protocol a 15s period of CPR during and after charging of the AED was added to the voice prompts and CPR was resumed immediately after defibrillation (modification of the Guidelines 2005). Survival was assessed at hospital admission and discharge., Results: Of 1174 OHCA patients, 456 met the inclusion criteria: 227 were randomly assigned to the experimental protocol and 229 to the control protocol. The experimental group experienced shorter pre-shock pauses (6 [5-11]s vs. 20 [18-23]s; P<0.001), and shorter post-shock pauses (7 [6-9]s vs. 27 [16-34]s; P<0.001). Similar proportions of patients survived to hospital admission (experimental: 62% vs., Control: 65%; RR [95%CI] 0.96 [0.83-1.10], P=0.51), and hospital discharge (experimental: 42% vs., Control: 38%; RR [95%CI] 1.09 [0.87-1.37], P=0.46)., Conclusion: In patients with OHCA and shockable initial rhythms, treatment with AEDs with the experimental protocol shortened pre-shock and post-shock CPR pauses, and increased overall CPR time, but did not improve survival to hospital admission or discharge., Clinical Trial Registration: http://www.isrctn.com unique identifier: ISRCTN72257677., (Copyright © 2016 The Author(s). Published by Elsevier Ireland Ltd.. All rights reserved.)

Purpose of Review: This article summarizes current knowledge of the causes and consequences of interruption of chest compressions during cardiopulmonary resuscitation., Recent Findings: Pauses in chest compressions occur during analysis of the heart rhythm, delivery of ventilation, interventions such as intubation, and gaining intravenous access, but pauses may also be unprompted. Pauses related to defibrillation are because of preshock pauses for rhythm analysis and charging, and postshock pauses to evaluate the outcome of the shock. Prolonged pauses, mainly preshock pauses (>10 s) are associated with decreased survival to discharge in retrospective analyses. Measures to reduce preshock and postshock pauses include resuming chest compressions during defibrillator charging, continued chest compression during defibrillation by mechanical chest compression devices or during manual chest compression with sufficiently insulating gloves for the rescuer, and eliminating postshock rhythm and pulse checks. New filtering techniques may allow rhythm analysis during chest compressions., Summary: It is important to avoid any unnecessary pause in chest compressions before and after a defibrillation shock. Pauses should be kept to an absolute minimum, preferably to less than 10 s.

This review comprises the most extensive literature search and evidence evaluation to date on the most important international BLS interventions, diagnostics, and prognostic factors for cardiac arrest victims. It reemphasizes that the critical lifesaving steps of BLS are (1) prevention, (2) immediate recognition and activation of the emergency response system, (3) early high-quality CPR, and (4) rapid defibrillation for shockable rhythms. Highlights in prevention indicate the rational and judicious deployment of search-and-rescue operations in drowning victims and the importance of education on opioid-associated emergencies. Other 2015 highlights in recognition and activation include the critical role of dispatcher recognition and dispatch-assisted chest compressions, which has been demonstrated in multiple international jurisdictions with consistent improvements in cardiac arrest survival. Similar to the 2010 ILCOR BLS treatment recommendations, the importance of high quality was reemphasized across all measures of CPR quality: rate, depth, recoil, and minimal chest compression pauses, with a universal understanding that we all should be providing chest compressions to all victims of cardiac arrest. This review continued to focus on the interface of BLS sequencing and ensuring high-quality CPR with other important BLS interventions, such as ventilation and defibrillation. In addition, this consensus statement highlights the importance of EMS systems, which employ bundles of care focusing on providing high-quality chest compressions while extricating the patient from the scene to the next level of care. Highlights in defibrillation indicate the global importance of increasing the number of sites with public-access defibrillation programs. Whereas the 2010 ILCOR Consensus on Science provided important direction for the “what” in resuscitation (ie, what to do), the 2015 consensus has begun with the GRADE methodology to provide direction for the quality of resuscitation. We hope that resuscitation councils and other stakeholders will be able to translate this body of knowledge of international consensus statements to build their own effective resuscitation guidelines.

Aim: Public access defibrillation rarely reaches out-of-hospital cardiac arrest (OHCA) patients in residential areas. We developed a text message (TM) alert system, dispatching local lay rescuers (TM-responders). We analyzed the functioning of this system, focusing on response times and early defibrillation in relation to other responders., Methods: In July 2013, 14112 TM-responders and 1550 automated external defibrillators (AEDs) were registered in a database residing with the dispatch center of two regions of the Netherlands. TM-responders living <1000m radius of the patient received a TM to go to the patient directly, or were directed to retrieve an AED first. We analyzed 1536 OHCA patients where a defibrillator was connected from February 2010 until July 2013. Electrocardiograms from all defibrillators were analyzed for connection and defibrillation time., Results: Of all OHCAs, the dispatcher activated the TM-alert system 893 times (58.1%). In 850 cases ≥1 TM-responder received a TM-alert and in 738 cases ≥1 AED was available. A TM-responder AED was connected in 184 of all OHCAs (12.0%), corresponding with 23.1% of all connected AEDs. Of all used TM-responder AEDs, 87.5% were used in residential areas, compared to 71.6% of all other defibrillators. TM-responders with AEDs defibrillated mean 2:39 (min:sec) earlier compared to emergency medical services (median interval 8:00 [25-75th percentile, 6:35-9:49] vs. 10:39 [25-75th percentile, 8:18-13:23], P<0.001). Of all shocking TM-responder AEDs, 10.5% delivered a shock ≤6min after call., Conclusion: A TM-alert system that includes local lay rescuers and AEDs contributes to earlier defibrillation in OHCA, particularly in residential areas., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Background: Self-directed BLS-training, using a personal training manikin with video has been shown to be as effective as instructor-led training. This has not previously been investigated for AED-training., Materials and Methods: This prospective, randomized study with a non-inferiority design compared traditional instructor-led training with three DVD-based AED-training methods (2.5min DVD without practice; 4.5min DVD with manikin practice; 9min DVD with manikin practice and scenario training). After DVD BLS-training, 396 participants were assigned to one of the four AED-training methods by randomization stratified for age. Participants were tested immediately after the training (post-test) and 2 months later (retention-test) using modified Cardiff criteria. The primary endpoint was the percentage of providers scoring 70% or higher on testing. The secondary endpoints were the mean scores and differences per item per age group., Results: Comparison non-inferiority could not be accepted for the post-test or retention-test. Relative risk (RR) and 95% confidence interval (CI) of passing for DVD without practice, with manikin practice and with manikin practice and scenario training compared to instructor-led training were 0.36 (0.25-0.53), 0.35 (0.24-0.51), 0.55 (0.38-0.79), respectively for the post-test, and 0.82 (0.68-0.97), 0.82 (0.68-0.97), and 0.84 (0.70-1.00), respectively for the retention-test. The performance of participants in all DVD-based training groups was significantly higher on the retention-test than on the post-test. Those receiving scenario training scored higher on the post-test compared to the other DVD-training groups (p<0.001)., Conclusions: DVD-based AED-training without scenario is not recommended. Scenario training is a useful addition, but instructor-facilitated training remains the best method., (Copyright 2010 Elsevier Ireland Ltd. All rights reserved.)

Background: This study aimed to determine whether automated external defibrillator (AED) use during resuscitation is associated with lower in-hospital health care costs., Methods: For this observational prospective study, we included all treated out-of-hospital cardiac arrests of suspected cardiac cause. Clinical, survival and cost data were collected from July 2005 until March 2008. Cost data were based on hospital transport, duration of admission in hospital wards, diagnostics and interventions. We divided the study population in three groups based on AED use: (1) onsite AED, (2) dispatched AED, (3) no AED. The endpoint was survival to discharge. P<0.05 is indicated by *., Results: Of the 2126 included patients, 136 were treated with an onsite AED, 365 with a dispatched AED and 1625 without AED. Overall (95% confidence interval [CI]) survival rate was 43% (35-51%), 16% (13-20%) and 14% (12-16%), respectively*. Per 100 survivors, the mean duration admitted at intensive care unit [ICU] were 267 (166-374), 495 (344-658), and 537 (450-609) days, respectively*; total duration of hospital admission was 2188 (1800-2594), 3132 (2573-3797), and 2765 (2519-3050) days, respectively*. Mean costs per survivor for hospital stay were euro9233 (euro7351-euro11,280), euro14,194 (euro11,656-euro17,254), and euro13,693 (euro12,226-euro15,166), respectively*; total health care costs were euro29,575 (euro24,695-euro34,183), euro34,533 (euro29,832-euro39,487) and euro31,772 (euro29,217-euro34,385), respectively. For both survivors and non-survivors, total costs per patient were euro14,727 (euro11,957-euro18,324), euro7703 (euro6141-euro9366) and euro6580 (euro5875-euro7238), respectively*., Conclusions: Onsite AED use was associated with higher survival rates. Surviving patients of the onsite AED group had lower total costs, mainly due to the shorter ICU stay., (Copyright 2010 Elsevier Ireland Ltd. All rights reserved.)

Introduction: The purpose of this study was to investigate whether the takeover by Advanced Life Support [ALS] trained ambulance paramedics from rescuers using an automated external defibrillator [AED] delays shocks and if this delay is associated with decreased survival after out-of-hospital cardiac arrest [OHCA]., Methods: We analyzed continuous ECG recordings of LIFEPAK AEDs and associated manual defibrillator recordings of OHCA of presumed cardiac cause, prospectively collected from July 2005 to July 2009. The primary outcome measure was survival to discharge. Among 693 patients treated with AEDs, 110 had a shockable initial rhythm and a shockable rhythm during ALS takeover. We measured the time interval between the expected shock if the AED would remain attached to the patient and the first observed shock given by the manual defibrillator [shock timing]., Results: Survival was 62% (13/21) if the shock was given early (<-20s), 52% (11/21; odds ratio [OR]=0.68, ns) if given on time (-20 to 20s), 29% (10/34; OR=0.26, 95% confidence interval [CI]=0.08-0.81; P=0.02) if the shock was 20-150s delayed and 21% (7/34; OR=0.16, 95% CI=0.05-0.54; P=0.003) if the shock was delayed >150s. The OR for trend was 0.41, 95% CI=0.25-0.71; P=0.001. The association between shock timing and survival was significant for patients with more than 150s shock delay (OR=0.19; 95% CI=0.04-0.71; P=0.02) or for trend in shock timing (0.42, 95% CI=0.20-0.84; P=0.02) after multivariable adjustment for prognostic factors age and slope of ventricular fibrillation., Conclusions: ALS takeover delays the next shock delivery in almost two-third of cases. This delay is associated with decreased survival., (Copyright 2009 Elsevier Ireland Ltd. All rights reserved.)

Background: Unlike Resuscitation Guidelines (GL) 2000, GL2005 advise resuming cardiopulmonary resuscitation (CPR) immediately after defibrillation. We hypothesized that immediate CPR resumption promotes earlier recurrence of ventricular fibrillation (VF)., Methods and Results: This study used data of a prospective per-patient randomized controlled trial. Automated external defibrillators used by first responders were randomized to either (1) perform postshock analysis and prompt rescuers to a pulse check (GL2000), or (2) resume CPR immediately after defibrillation (GL2005). Continuous recordings of ECG and impedance signals were collected from all patients with an out-of-hospital cardiac arrest to whom a randomized automated external defibrillator was applied. We included patients with VF as their initial rhythm in whom CPR onset could be determined from the ECG and impedance signals. Time intervals are presented as median (Q1-to-Q3). Of 361 patients, 136 met the inclusion criteria: 68 were randomly assigned to GL2000 and 68 to GL2005. Rescuers resumed CPR 30 (21-to-39) and 8 (7-to-9) seconds, respectively, after the first shock that successfully terminated VF (P<0.001); VF recurred after 40 (21-to-76) and 21 (10-to-80) seconds, respectively (P=0.001). The time interval between start of CPR and VF recurrence was 6 (0-to-67) and 8 (3-to-61) seconds, respectively (P=0.88). The hazard ratio for VF recurrence in the first 2 seconds of CPR was 15.5 (95% confidence interval, 5.63 to 57.7) compared with before CPR resumption. After more than 8 seconds of CPR, the hazard of VF recurrence was similar to before CPR resumption., Conclusions: Early CPR resumption after defibrillation causes early VF recurrence. Clinical Trial Registration- clinicaltrials.gov Identifier: ISRCTN72257677.

Objective: Technical data now gathered by automated external defibrillators (AEDs) allows closer evaluation of the behavior of defibrillation shocks administered during out-of-hospital cardiac arrest. We analyzed technical data from a large case series to evaluate the change in transthoracic impedance between shocks, and to assess the heterogeneity of the probability of successful defibrillation across the population., Methods: We analyzed a series of consecutive cases where AEDs delivered shocks to treat ventricular fibrillation (VF) during out-of-hospital cardiac arrest. Impedance measurements and VF termination efficacy were extracted from electronic records downloaded from biphasic AEDs deployed in three EMS systems. All patients received 200J first shocks; second shocks were 200J or 300J, depending on local protocols. Results presented are median (25th, 75th percentiles)., Results: Of 863 cases with defibrillation shocks, 467 contained multiple shocks because the first shock failed to terminate VF (n=61) or VF recurred (n=406). Defibrillation efficacy of subsequent shocks was significantly lower in patients that failed to defibrillate on first shock than in patients that did defibrillate on first shock (162/234=69% vs. 955/1027=93%; p<0.0001). The failed VF terminations were distributed heterogeneously across the population; 5% of patients accounted for 71% of failed shocks. Shock impedance decreased by 1% [0%, 4%] and peak current increased by 1% [0%, 4%] between 200J first and 200J second shocks. Shock impedance decreased 4% [2%, 6%] and current increased 27% [25%, 29%] between 200J first and 300J second shocks. In all 499 pairs of same-energy consecutive shocks, impedance changed by less than 1% in 226 (45%), increased >1% in 124 (25%) and decreased >1% in 149 (30%)., Conclusions: Impedance change between consecutive shocks is minimal and inconsistent. Therefore, to increase current of a subsequent shock requires an increase of the energy setting. Distribution of failed shocks is far from random. First shock defibrillation failure is often predictive of low efficacy for subsequent shocks.

Aim of the Study: The response of recurrent episodes of ventricular fibrillation (VF) to defibrillation shocks has not been systematically studied. We analyzed outcomes from countershocks delivered for VF during advanced life support (ALS) care of patients with out-of-hospital cardiac arrest., Methods: Cohort of patients with prehospital cardiac arrest presenting with VF, treated by ALS ambulance staff following ERC Guidelines 2000. Biphasic defibrillators provided shocks increasing from 200 to 360J. Recorded signals were analyzed to determine, for each shock, if VF was terminated and if a sustained organized rhythm was restored within 60s., Results: In 465 of the 467 patients enrolled, the initial VF episode was terminated within three shocks: 92%, 61%, and 83% responded to 200J first, 200J second and 360J third shocks, respectively. VF recurred in 48% of patients within 2min of the first episode, and in 74% sometime during prehospital care. In the 175 patients experiencing five or more VF episodes, single shock VF termination dropped from the first to the fifth episode (90-80%, p<0.001) without change in transthoracic impedance, yet the proportion returning to organized rhythms increased (11-42%, p<0.0001)., Conclusions: Repeated refibrillation is common in patients with VF cardiac arrest. The likelihood of countershocks to terminate VF declines for repeated episodes of VF, yet shocks that terminate these episodes result increasingly in a sustained organized rhythm.

Objectives: The definition of defibrillation shock "success" endorsed by the International Liaison Committee on Resuscitation since the publication of Guidelines 2000 for Cardiopulmonary Resuscitation and Emergency Cardiac Care has been removal of ventricular fibrillation at 5 secs after shock delivery. Although this success criterion provides a direct assessment of the primary task of a shock, it may not be the only clinically useful measure of shock outcome. We evaluated a different defibrillation success criterion to determine whether it could provide additional insight into the relative performance of different defibrillation shocks., Design: A randomized study comparing monophasic and biphasic waveform shocks is reported with return of organized rhythm as the primary outcome measure of defibrillation success., Patients: A total of 120 patients with out-of-hospital ventricular fibrillation as the first recorded rhythm were treated with defibrillation with automated external defibrillators., Measurements and Main Results: Return of organized rhythm (two QRS complexes, <5 secs apart, <60 secs after defibrillation) was achieved in 31 monophasic shock (45%) and 35 biphasic shock (69%) patients (relative risk, 1.53, 95% confidence interval, 1.11-2.10). Logistic regression analysis revealed that shock waveform was the strongest independent predictor of return of organized rhythm (odds ratio, 4.0; 95% confidence interval, 1.67-10.0). Defibrillation success with the conventional International Liaison Committee on Resuscitation criterion was very high (91% and 98%, respectively) and not significantly different between groups., Conclusions: Return of organized rhythm proved to be a more sensitive measure of relative defibrillation shock performance than the conventional shock success criterion. Inclusion of return of organized rhythm as an end point in future clinical research could help discern more subtle defibrillation shock effects and contribute to further optimization of defibrillation technology.

Background: Early defibrillation results in higher admission rates and healthcare costs. This study determined the healthcare resources used and related medical costs after out-of-hospital cardiac arrest (OHCA) in relation to time to shock. We assessed the incremental healthcare costs per life gained from reduction in time to shock of 2, 4, and 6 minutes., Methods and Results: Clinical and costs data of patients in witnessed OHCA with ventricular fibrillation as initial rhythm were collected. Each patient's time to shock was estimated and assigned to 1 of 3 categories: < or =7 minutes (early), 7 to 12 minutes (intermediate), and >12 minutes (late). Incremental cost-effectiveness analysis and Monte Carlo simulation compared scenarios of reduction in time to shock of 2, 4, and 6 minutes. Six-month survival was 22%. Mean prehospital, in-hospital, and posthospital costs in the first half-year after OHCA were 559 Euros, 6869 Euros and 666 Euros. Mean costs were 28,636 Euros per survivor and 2384 Euros per nonsurvivor. Among patients shocked early (n=24), 46% survived, with costs averaging 20,253 Euros. Of the intermediate group (n=149), 26% survived, with costs averaging 31,467 Euros. Among patients shocked late (n=135), 13% survived, with costs averaging 27,781 Euros. The point estimates of the incremental cost-effectiveness ratios of reduction of time to shock of 2, 4, and 6 minutes compared with baseline were 17,508 Euros, 14,303 Euros, and 12,708 Euros per life saved, respectively., Conclusions: Costs per survivor were lowest with the shortest time to shock because of shorter stay in the intensive care unit. Reducing the time to defibrillation increases the healthcare costs by an acceptable amount according to current standards and is economically attractive.

Background: We compared efficacy of and pain felt after biphasic truncated exponential (BTE) and monophasic damped sine (MDS) shocks in patients undergoing external cardioversion of atrial fibrillation (AF)., Methods: Patients with AF were randomized to BTE or MDS waveform cardioversion. Successive shocks were delivered at 70, 100, 200, and 360 J until successful cardioversion, with one 360 J attempt of the alternate waveform when all 4 shocks failed. Success was determined by blinded over-read of electrocardiograms. Peak current was calculated from energy and impedance. Patients rated their pain at 1 and 24 hours after cardioversion., Results: Fourteen of 37 (38%) patients treated with MDS and 34 of 35 (97%) treated with BTE shocks were cardioverted at < or =200 J (P <.0001). Success rates of MDS versus BTE shocks were 5.4% versus 60% for 70 J, 19% versus 80% for < or =100 J, and 86% versus 97% for < or =360 J. BTE shocks cardioverted with less peak current (14.0 +/- 4.3 vs 39.5 +/- 11.2 A, P <.0001), less energy (97 +/- 47 vs 278 +/- 120 J, P <.0001), and less cumulative energy (146 +/- 116 vs 546 +/- 265 J, P <.0001). Patients felt less pain after BTE than MDS shocks at 1 hour (P <.0001) and 24 hours (P <.0001) after cardioversion., Conclusion: This BTE waveform is superior to the MDS waveform for cardioversion of AF, requiring much less energy and current, and causing less postprocedural pain.

Objective: To test the hypothesis that the use of an automated external defibrillator by police and fire fighters results in higher discharge rates for out of hospital cardiac arrest., Design: Controlled clinical trial with initial random allocation of automated external defibrillators to first responders in four of the eight participating regions; each region switched from control to experimental, and vice versa, every four months., Setting: Amsterdam and surroundings, the Netherlands., Participants: Patients with witnessed out of hospital cardiac arrests, identified by the emergency medical system between January 2000 and January 2002., Main Outcomes Measures: Survival to hospital discharge; return of spontaneous circulation; admission to hospital., Results: 243 patients (65% in ventricular fibrillation) were included in the experimental area and 226 patients (67% in ventricular fibrillation) in the control area. The median time interval between collapse and first shock was 668 seconds in the experimental area and 769 seconds in the control area (P < 0.001). 44 (18%) patients in the experimental area versus 33 (15%) patients in the control area were discharged (odds ratio 1.3 (95% confidence interval 0.8 to 2.2), P = 0.33), 139 (57%) experimental versus 108 (48%) control patients had return of spontaneous circulation (1.5 (1.0 to 2.2), P = 0.05), and 103 (42%) experimental versus 74 (33%) control patients were admitted (1.5 (1.1 to 1.6), P = 0.02). The median delay from receipt of call to dispatch of the ambulance was 120 seconds, and the delay to dispatch of the first responder was 180 seconds., Conclusions: Use of automated external defibrillators by first responders did not significantly increase survival to discharge from hospital, although it did improve return of spontaneous circulation and admission to hospital. Improved dispatch procedures should increase the success of programmes of first responders using external defibrillators.

Background: Refibrillation after successful defibrillation in out-of-hospital cardiac arrest is a frequent event. Little is known of factors that predispose to the occurrence of refibrillation. The effect of recurrence of ventricular fibrillation (VF) on survival is not known., Methods: Data of patients in out-of-hospital cardiac arrest were collected in a combined first responder and paramedic programme in Amsterdam, the Netherlands. Continuous recorded rhythm data of 322 patients covering the entire out-of-hospital resuscitation attempt was included in the analysis. Recurrence of VF was recorded, the patient and process characteristics were analysed in relation to the occurrence of refibrillation. The number of refibrillations was related to survival., Results and Conclusion: Of the studied patients 79% had at least one recurrence of VF, and a median number of two times 25-75%; one to four times). The median time from successful first shock to VF recurrence was 45 s (25-75%: 23-115 s). A significant inverse relation was found between the number of refibrillations and survival of out-of-hospital cardiac arrest. The recurrence of VF was independent of the underlying cardiac disorder, the time to defibrillation, the defibrillation waveform and other characteristics of the patient and the process. Anti-arrhythmics should be considered in all patients found in VF to reduce the number of recurrences.

Study Objective: The protocol for the use of the automated external defibrillator calls for a period of "hands-off" time, during which no cardiopulmonary resuscitation (CPR) can be performed. We assessed the actual interruption time of CPR during the use of the automated external defibrillator in patients in out-of-hospital cardiac arrest., Methods: This study included 184 patients experiencing out-of-hospital cardiac arrest in which an automated external defibrillator was applied by first responders. ECG and voice recordings from the automated external defibrillator were downloaded and analyzed. Start and end times of CPR were recorded, as were intervals measured from the recordings concerning the programmed interruption time and the interruption time related to performance., Results: The automated external defibrillators were connected for a median time of 4 minutes 47 seconds (range 31 to 1,404 seconds). CPR was performed during 45%+/-15% (mean+/-SD) of the connected time or until return of spontaneous circulation. During the automated external defibrillator connection time in the 96 patients with a shockable rhythm, CPR was performed 36%+/-20% of the time. Programmed interruption of CPR took 40%+/-15% of the automated external defibrillator connection time, and no CPR was performed related to performance during 23%+/-15% of the time. A palpable pulse was never present immediately after a shock, and return of spontaneous circulation was observed in 3 of 184 patients before arrival of the ambulance. Ultimately, return of spontaneous circulation occurred in 87 of 184 patients., Conclusion: First responders using automated external defibrillator voice prompts provide CPR less than half the time that the automated external defibrillator is connected to the patient. Technical improvements in automated external defibrillator rhythm analysis, more efficient resuscitation algorithms, and first-responder education could increase CPR delivery and, perhaps, improve outcome.

Background: Evidence suggests that biphasic waveforms are more effective than monophasic waveforms for defibrillation in out-of-hospital cardiac arrest (OHCA), yet their performance has only been compared in un-blinded studies., Methods and Results: We compared the success of biphasic truncated exponential (BTE) and monophasic damped sine (MDS) shocks for defibrillation in OHCA in a prospective, randomised, double blind clinical trial. First responders were equipped with MDS and BTE automated external defibrillators (AEDs) in a random fashion. Patients in ventricular fibrillation (VF) received BTE or MDS first shocks of 200 J. The ECG was recorded for subsequent analysis continuously. The success of the first shock as a primary endpoint was removal of VF and required a return of an organized rhythm for at least two QRS complexes, with an interval of <5 s, within 1 min after the first shock. The secondary endpoint was termination of VF at 5 s. VF was the initial recorded rhythm in 120 patients in OHCA, 51 patients received BTE and 69 received MDS shocks. The success rate of 200 J first shocks was significantly higher for BTE than for MDS shocks, 35/51 (69%) and 31/69 (45%), P=0.01. In a logistic regression model the odds ratio of success for a BTE shock was 4.01 (95% CI 1.01-10.0), adjusted for baseline cardiopulmonary resuscitation, VF-amplitude and time between collapse and first shock. No difference was found with respect to the secondary endpoint, termination of VF at 5 s (RR 1.07 95% CI: 0.99-1.11) and with respect to survival to hospital discharge (RR 0.73 95% CI: 0.31-1.70)., Conclusion: BTE-waveform AEDs provide significantly higher rates of successful defibrillation with return of an organized rhythm in OHCA than MDS waveform AEDs.

Introduction: Sudden cardiac death is a major health problem. Worldwide success of resuscitation from out-of-hospital cardiac arrest is modest, with 5% to 10% survival to hospital discharge., Methods and Results: In the chain of survival, early defibrillation (goal <5 min after collapse) is a major determinant of successful outcome of resuscitation. This goal is rarely achieved, but the automatic external defibrillator (AED) is a promising tool for lay defibrillation. The AED is a safe and effective device with nearly 100% accurate detection of ventricular fibrillation and nearly 100% accurate detection of a nonshockable rhythm. A large uncontrolled experience suggests improved outcome in nontraditional responders such as police. Controlled studies of community application of the AED are under way., Conclusion: The AED is a promising tool in the fight against sudden cardiac death and should be studied and supported by all scientists involved, including electrophysiologists.

Application of the automatic external defibrillator can improve the chance of success during resuscitation of out-of-hospital cardiac arrest, because lay persons can defibrillate awaiting the arrival of the ambulance. Defibrillation is mentioned in the Dutch Individual Health Care Professionals Act as a precluded action. Defibrillation with an automatic external defibrillator should be excluded from the list of precluded actions, because application is almost 100% safe and because the subject is not within the scope of the law which is restricted to professional activities and non-emergency actions. Defibrillation with an automatic external defibrillator is acceptable.

Ventricular fibrillation (VF) and transient arrhythmias after defibrillation were analyzed from the recordings of 28 patients containing at least one episode of ventricular fibrillation. An R-on-T extrasystole initiated VF in 60% of the episodes. Other initiating factors were a late premature beat (24%), stable ventricular tachycardia (VT) (7%), accelerating idioventricular rhythm (5%) and cardioversion of VT (5%) with a sinusoidal waveform. After the initiating beat, in most cases, evidence was found of a transient ventricular tachycardia which then deteriorated into VF. With a stable VT this may occur after a long time; in the case of apolymorphic VT (with changing amplitude) it generally occurred within 30 s. The main transient arrhythmias generated by circulatory arrest during VF and by the defibrillation shock were: total arrest, total AV-block and/or bradycardia. The combination of a longer duration of VF and a high energy level generally resulted in an increase in the duration of these arrhythmias (P less than 0.01, N = 30). Comparison of episodes of VT and VF recorded in a single patient also shows that arrhythmias are more unfavourable and of longer duration after VF than after VT. These data emphasize fast defibrillation, initially with stored energy levels less than 250J.