Remote synchronous usability testing of public access defibrillators during social distancing in a pandemic.

Public access automated external defibrillators (AEDs) represent emergency medical devices that may be used by untrained lay-persons in a life-critical event. As such their usability must be confirmed through simulation testing. In 2020 the novel coronavirus caused a global pandemic. In order to reduce the spread of the virus, many restrictions such as social distancing and travel bans were enforced. Usability testing of AEDs is typically conducted in-person, but due to these restrictions, other usability solutions must be investigated. Two studies were conducted, each with 18 participants: (1) an in-person usability study of an AED conducted in an office space, and (2) a synchronous remote usability study of the same AED conducted using video conferencing software. Key metrics associated with AED use, such as time to turn on, time to place pads and time to deliver a shock, were assessed in both studies. There was no difference in time taken to turn the AED on in the in-person study compared to the remote study, but the time to place electrode pads and to deliver a shock were significantly lower in the in-person study than in the remote study. Overall, the results of this study indicate that remote user testing of public access defibrillators may be appropriate in formative usability studies for determining understanding of the user interface.

Lower rate limit for pacing by cardiac resynchronization defibrillators: Should lower rate programming be reconsidered?

BACKGROUND: No real-world large database associates lower rate limit (LRL) programming and survival of subjects with cardiac resynchronization therapy-defibrillators (CRT-Ds). OBJECTIVE: The purpose of this study was to test the hypothesis that lower LRL programming is independently associated with survival, and that LRL and heart rate score (HrSc) are associated. METHODS: All dual-chamber CRT-D devices in the Remote Patient Monitoring (RPM) ALTITUDE database (2006-2011) were queried. Baseline HrSc was defined as the percentage of all atrial sensed and paced beats in the tallest 10-beat histogram bin postimplant. LRL was assessed during repeated RPM uploads. Using a Cox model multivariable analysis, relationships between LRL, survival, HrSc, and other variables were evaluated. Survival was determined by query of death indices. RESULTS: Data analyzed included 61,881 subjects (mean follow-up 2.9 years). LRL ranged from 40 to 85 bpm. Baseline lower LRL was associated with younger age, less atrial fibrillation, female sex, and lower HrSc (P <.001 for all covariates). Lower LRL was associated with improved survival, with LRL 40 associated with the largest survival benefit. This was significant for all 3 HrSc subgroups (P <.001). An interaction between HrSc and LRL was observed, with the largest survival difference between HrSc groups observed at LRL-40 (P <.001). CONCLUSION: LRL programming and HrSc were associated, and lower values of both were associated with improved survival in a large database of CRT-D subjects. Relationships between survival, LRL programming, and HrSc merit further study.

Bystander Cardiopulmonary Resuscitation Quality: Potential for Improvements in Cardiac Arrest Resuscitation.

Background Bystander cardiopulmonary resuscitation (CPR) is a critical intervention to improve survival following out-of-hospital cardiac arrest. We evaluated the quality of bystander CPR and whether performance varied according to the number of bystanders or provision of telecommunicator CPR (TCPR). Methods and Results We investigated non-traumatic out-of-hospital cardiac arrest occurring in a large metropolitan emergency medical system during a 6-month period. Information about bystander care was ascertained through review of the 9-1-1 recordings in addition to emergency medical system and hospital records to determine bystander CPR status (none versus TCPR versus unassisted), the number of bystanders on-scene, and CPR performance metrics of compression fraction and compression rate. Of the 428 eligible out-of-hospital cardiac arrest, 76.4% received bystander CPR including 43.7% unassisted CPR and 56.3% TCPR; 35.2% had one bystander, 33.3% had 2 bystanders, and 31.5% had ≥3 bystanders. Overall compression fraction was 59% with a compression rate of 88 per minute. CPR differed according to TCPR status (fraction=52%, rate=87 per minute for TCPR versus fraction=69%, rate=102 for unassisted CPR, P<0.05 for each comparison) and the number of bystanders (fraction=55%, rate=87 per minute for 1 bystander, fraction=59%, rate=89 for 2 bystanders, fraction=65%, rate=97 for ≥3 bystanders, test for trend P<0.05 for each metric). Additional bystander actions were uncommon to include rotation of compressors (3.1%) or application of an automated external defibrillator (8.0%). Conclusions Bystander CPR quality as gauged by compression fraction and rate approached guideline goals though performance depended upon the type of CPR and number of bystanders.

Primary Results From the Understanding Outcomes With the S-ICD in Primary Prevention Patients With Low Ejection Fraction (UNTOUCHED) Trial.

BACKGROUND: The subcutaneous (S) implantable cardioverter-defibrillator (ICD) is safe and effective for sudden cardiac death prevention. However, patients in previous S-ICD studies had fewer comorbidities, had less left ventricular dysfunction, and received more inappropriate shocks (IAS) than in typical transvenous ICD trials. The UNTOUCHED trial (Understanding Outcomes With the S-ICD in Primary Prevention Patients With Low Ejection Fraction) was designed to evaluate the IAS rate in a more typical, contemporary ICD patient population implanted with the S-ICD using standardized programming and enhanced discrimination algorithms. METHODS: Primary prevention patients with left ventricular ejection fraction ≤35% and no pacing indications were included. Generation 2 or 3 S-ICD devices were implanted and programmed with rate-based therapy delivery for rates ≥250 beats per minute and morphology discrimination for rates ≥200 and <250 beats per minute. Patients were followed for 18 months. The primary end point was the IAS-free rate compared with a 91.6% performance goal, derived from the results for the ICD-only patients in the MADIT-RIT study (Multicenter Automatic Defibrillator Implantation Trial-Reduce Inappropriate Therapy). Kaplan-Meier analyses were performed to evaluate event-free rates for IAS, all-cause shock, and complications. Multivariable proportional hazard analysis was performed to determine predictors of end points. RESULTS: S-ICD implant was attempted in 1116 patients, and 1111 patients were included in postimplant follow-up analysis. The cohort had a mean age of 55.8±12.4 years, 25.6% were women, 23.4% were Black, 53.5% had ischemic heart disease, 87.7% had symptomatic heart failure, and the mean left ventricular ejection fraction was 26.4±5.8%. Eighteen-month freedom from IAS was 95.9% (lower confidence limit, 94.8%). Predictors of reduced incidence of IAS were implanting the most recent generation of device, using the 3-incision technique, no history of atrial fibrillation, and ischemic cause. The 18-month all-cause shock-free rate was 90.6% (lower confidence limit, 89.0%), meeting the prespecified performance goal of 85.8%. Conversion success rate for appropriate, discrete episodes was 98.4%. Complication-free rate at 18 months was 92.7%. CONCLUSIONS: This study demonstrates high efficacy and safety with contemporary S-ICD devices and programming despite the relatively high incidence of comorbidities in comparison with earlier S-ICD trials. The inappropriate shock rate (3.1% at 1 year) is the lowest reported for the S-ICD and lower than many transvenous ICD studies using contemporary programming to reduce IAS. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02433379.

Insufficient quality of public automated external defibrillator recordings in the greater Paris area, a descriptive study.

BACKGROUND: Western countries report a significant increase in the proportion of patients who experience out-of-hospital cardiac arrests (OHCAs) and benefit from a public automated external defibrillator (pAED) before the arrival of rescue teams. However, recordings of devices recovered after resuscitation are of variable quality. Analysis of these data may inform decisions of whether to implement an internal defibrillator for survivors, and provide useful information about the performance of pAED algorithms and the actions of bystanders. OBJECTIVE: To investigate the quality of the information recorded by pAEDs during OHCAs in the Paris area. METHODS: pAED files used for some of the 8629 OHCAs that occurred in the greater Paris area between 1 January 2017 and 31 April 2019 on the day of the arrest were collected. The presence and accuracy of 23 factors required to interpret the recording was noted, including readability of the ECG, the presence of an impedance curve and the accuracy of the date and time. The recordings were analysed to assess the diagnostic and therapeutic performance of the pAEDs used. RESULTS: A total of 258 patients with an OHCA received assistance from a pAED, and 182 recordings were recovered. The pAEDs were made by 12 different manufacturers. Data extraction required eight different transmission modes and 16 software programmes; recordings were of highly heterogeneous quality. Two per cent of the recordings were of such poor quality that they were not interpretable. Among the 98% remaining, only 43% included a thoracic impedance curve, 34% the intensity of the shocks delivered and 8% the patient name. The date and time were accurate in 68% and 48% of recordings, respectively. The pAEDs had 87.6% (95% CI 83.7% to 91.0%) sensitivity and 99.5% (99.5% to 99.5%) specificity for defibrillating shockable rhythms (positive predictive value 98.2% (96.4% to 99.0%), negative predictive value 96.4% (95.3% to 96.8%)). The absence of important variables prevented the analysis of approximately half of the inappropriate decisions made by pAEDs. CONCLUSION: Collection of pAED recordings is a major challenge. Their analysis is compromised by heterogeneity and poor quality (incomplete maintenance records, patient details and logs). AED recordings are currently the most relevant resource to track pAED performance and bystander practices. The quality of these recordings needs to improve.

Assessment on CPR Knowledge and AED Availability in Saudi Malls by Security Personnel: Public Safety Perspective.

Security personnel are the first ones who attend the scene in the case of out-of-hospital cardiac arrest (OHCA) at malls. Cardiopulmonary resuscitation (CPR) is not enough for those patients; they need an automated external defibrillator (AED) to bring the heart to function normally. This study aimed to assess the current status of CPR and AED knowledge and availability in Saudi malls by security personnel. Using a descriptive design, a study was conducted at seven malls located in the Eastern Province of Saudi Arabia. Two hundred and fifty participants were surveyed using the American Heart Association (AHA) 2015 guidelines to assess CPR and AED knowledge and availability in Saudi malls. The sample mean age was 32.60 years (SD = 10.02), and 87% of participants were working as security personnel. The majority of the participants had not received training about CPR and AED (75.8% and 95.2%, respectively). Common misconceptions are fallen into all categories of CPR and AED knowledge. Correctly answered statements ranged from 7.2% in the compression rate to 24.2% in hand placement. The study results indicated a poor training knowledge of CPR and AED in public settings. Integrating high-quality CPR and AED knowledge within the school and college curricula is a vital need. However, in order to maximize the survival rate, it is important to set laws and legislation adopted by stakeholders and decision makers to advocate the people who try to help, mandate AED installation in crowded places, and mandate teaching hands-only CPR and AED together as a package.

Regulación de la desfibrilación externa semiautomática fuera del entorno sanitario en las comunidades autónomas de España: situación actual / Regulations for using semiautomatic external defibrillators outside health care settings in Spain: a review and comparison of the current situation across autonomous communities

El objetivo de este trabajo es comparar las legislaciones autonómicas españolas en materia de formación, utilización y obligatoriedad de la instalación de desfibriladores externos automatizados (DEA) fuera del ámbito sanitario y analizar la variabilidad territorial con que se han desarrollado las regulaciones. Llevamos a cabo una revisión de las normativas publicadas en los boletines oficiales de las 17 comunidades autónomas y las 2 ciudades autónomas de España hasta mayo de 2019, extrayendo datos referidos a la regulación de la formación, el uso y la instalación de los DEA fuera del ámbito sanitario. Observamos que médicos y enfermeros están autorizados a utilizar los DEA, salvo en Murcia, donde únicamente tienen autorizado su uso los médicos. En 14 comunidades autónomas también se consideran habilitados los técnicos en emergencias sanitarias. Excepto en el País Vasco, donde cualquier ciudadano puede utilizar un DEA previa alerta a los servicios de emergencia, es necesario realizar un curso inicial acreditado para estar habilitado en el uso de estos dispositivos (cuya duración varía, según la comunidad, entre 4 y 9 horas) y debe ser renovado con una periodicidad que oscila entre uno y 3 años. Sin embargo, 11 comunidades permiten que, en caso de emergencia y en ausencia de personal habilitado, cualquier ciudadano pueda utilizar un DEA, previa alerta a los servicios de emergencia. Once autonomías regulan la obligación de instalar DEA fuera del ámbito sanitario. Se concluye que si bien todas las comunidades autónomas de España disponen de una normativa reguladora del uso y la acreditación de DEA, el mapa legislativo es muy diverso, por lo que sería deseable una política armonizadora para unificar criterios e incentivar el uso de estos dispositivos en caso de necesidad

We compared Spanish autonomous communities' regulations affecting the use of semiautomatic external defibrillators (semi-AEDs), including requirements for training and providing devices outside health care settings. We analyzed differences in the development of regulations across the different geographic areas. Regulations published in the official bulletins of Spain’s 17 autonomous communities and 2 autonomous cities in effect in May 2019 were reviewed to extract directives affecting training, authorized use, and the provision of semi-AEDs outside health care centers. We found that both doctors and nurses are authorized to use the devices in most communities, with the exception of Murcia, where only doctors may use them. Fourteen communities also authorize emergency responders to operate semi-AEDs. Other individuals must call for emergency help before using one, and specific rules vary by community. In the Basque Country anyone may use them, but in other communities, only individuals who have taken a training course on how to use a semi-AED may. The duration of training programs varies from 4 to 9 hours in different parts of Spain, and retraining is required at intervals that vary from 1 to 3 years. However, in 11 communities any citizen may use a semi-AED in an emergency in which authorized persons are not present (after first calling for emergency responders). Eleven autonomous communities regulate the required provision of semi-AEDs outside health care centers. We conclude that although Spain’s autonomous communities have regulations in place for the use of these devices, the regulatory map is highly diverse. Therefore, we think that harmonization is desirable in the interest of unifying criteria and encouraging the use of semi-AEDs when they are needed

Ascending Defibrillation Waveform Significantly Reduces Myocardial Morphological Damage and Injury Current.

OBJECTIVES: This study tested the hypothesis that a biphasic defibrillation waveform with an ascending first phase (ASC) causes less myocardial damage by pathology and injury current than a standard biphasic truncated exponential (BTE) waveform in a swine model. BACKGROUND: Although lifesaving, defibrillation shocks have significant iatrogenic effects that reduce their benefit for patient survival. METHODS: An ASC waveform with an 8-ms linear ramp followed by an additional positive 0.5-ms decaying portion with amplitudes of 20 J (ASC 20J) and 25 J (ASC 25J) was used. The control was a 25-J BTE conventional waveform (BTE 25J) RESULTS: The ASC 20J and ASC 25J shocks were both successful in 6 of 6 pigs, but the BTE 25J was successful in only 6 of 14 pigs (p < 0.05). Post-shock ST-segment elevation (injury current) in the right ventricular electrode was significantly greater with BTE 25J than with ASC 20J and ASC 25J. With a blinded pathology reading, hemorrhage, inflammation, thrombi, and necrosis 24 h post-shock were significantly greater with BTE 25J than with ASC 20J and ASC 25J. Troponin levels were also markedly lower at 3, 4, 5, and 6 h post-shock. CONCLUSIONS: Defibrillation shocks cause electrophysiological, histological, and biochemical signs of myocardial damage and necrosis. These signs of damage are markedly less for an ASC waveform than for a conventional BTE waveform.

The effectiveness of teaching chest compression first in a standardized public cardiopulmonary resuscitation training program.

Effectiveness of bystander cardiopulmonary resuscitation (CPR) is known to provide emergency medical services which reduce the number of deaths in patients with out-of-hospital cardiac arrest. The survival at these patients is affected by the training level of the bystander, but the best format of CPR training is unclear. In this pilot study, we aimed to examine whether the sequence of CPR instruction improves learning retention on the course materials.A total of 95 participants were recruited and divided into 2 groups; Group 1: 49 participants were taught firstly how to recognize a cardiac arrest and activate the emergency response system, and Group 2: 46 participants were taught chest compression first. The performance of participants was observed and evaluated, the results from 1 pre-test and 2 post-tests between 2 groups were then compared.There was a significantly better improvement of participants in Group 2 regarding the recognition of a cardiac arrest and the activation of the emergency response system than of those in Group 1. At the post-test, participants in Group 2 had an improvement in chest compression compared to those in Group 1, but the difference was not statistically significant.Our study had revealed that teaching CPR first in a standardized public education program had improved the ability of participants to recognize cardiac arrest and to activate the emergency response system.

High-dose melphalan and autologous peripheral blood stem cell transplantation in patients with AL amyloidosis and cardiac defibrillators.

Cardiac deposition of misfolded light chains is the leading cause of morbidity and mortality in patients with immunoglobulin (AL) amyloidosis. Cardiac defibrillators can be used in the management of patients with advanced cardiac amyloidosis, but data concerning the use of these devices in patients undergoing treatment with high-dose melphalan followed by autologous peripheral blood stem cell transplantation (HDM/SCT) is limited. Herein we describe a single-institution experience of HDM/SCT in 15 patients with cardiac defibrillators. During the peri-transplant period, five of these patients (33%) had detectable cardiac arrhythmias and two patients (13%) had implantable cardiac defibrillator (ICD) discharges. Thirteen of the 14 evaluable patients (93%) achieved at least a partial hematologic response. Transplant-related mortality was 6.7% and median overall survival was 40.8 months, with multiple patients achieving an overall survival of >10 years. These data highlight the feasibility of HDM/SCT in patients with an ICD due to advanced cardiac AL amyloidosis, but highlight the need for additional research to appropriately determine which patients will benefit from this aggressive therapy.

Long-term use of the wearable cardioverter defibrillator in patients with explanted ICD.

OBJECTIVES: To evaluate the effectiveness of wearable cardioverter defibrillator (WCD) use in protecting patients from sudden cardiac arrest (SCA) while they were treated in nonhospital settings until re-implantation of an Implantable cardioverter-defibrillator (ICD) was feasible. We sought to determine whether the WCD could be successfully utilized long term (≥1 year) after ICD extraction in patients at continued risk of SCD in which ICD re-implantation was not practical. BACKGROUND: ICDs have proven to improve mortality in patients for both secondary and primary prevention of SCA. Increased ICD implantation in older patients with comorbid conditions has resulted in higher rates of cardiac device infections. Currently, a wearable cardioverter defibrillator (WCD) is an alternative management for SCA prevention in specific cases. METHODS: This a retrospective analysis based on consecutive WCD patients who underwent ICD explant due to device-related infections or mechanical reasons between April 2007 and July 2014. A total of 102 patients were identified from the national database maintained by ZOLL (Pittsburgh, PA, USA). We analyzed the reason for WCD use, demographic information, device data, compliance and duration of WCD use, detected arrhythmias and therapies, and reason for discontinuing WCD use. RESULTS: In these long term WCD users, average length of WCD use was 638 ±â€¯361 days. Nine patients (8.8%) had a sustained ventricular arrhythmia that was successfully resuscitated by the WCD. Six patients (5.8%) experienced inappropriate shocks. Two patients (1.9%) died of asystole events while wearing the WCD and an additional 10 patients died while not monitored by the WCD. Thirty-nine patients (38.2%) ended WCD use when a new ICD was implanted and 15 patients (14.7%) were still wearing the WCD at the time of analysis. CONCLUSIONS: We found that extending use of the WCD to ≥1 year is a safe and effective alternative treatment for patients with explanted ICDs who are not pacemaker dependent.

Performance of automated external defibrillators under conditions of in-flight turbulence.

INTRODUCTION: Modern automated external defibrillators (AEDs) are designed to prevent shock delivery when excessive motion produces rhythm disturbances mimicking ventricular fibrillation (VF). This has been reported as a safety issue in airline operations, where turbulent motion is commonplace. We aimed to evaluate whether all seven AEDs can deliver shock appropriately in a flight simulator under turbulent conditions. METHODS: The study was performed in a Boeing 747-400 full motion flight simulator in Hong Kong. An advanced life support manikin and arrhythmia generator were used to produce sinus rhythm (SR), asystole, and five amplitudes of VF, with a programmed change to SR in the event of an effective shock being delivered. All rhythms were tested at rest (no turbulence) and at four levels of motion (ground taxi vibration, and mild, moderate and severe in-flight turbulence). Success was defined as: 1. effective shock being delivered where the rhythm was VF successfully converted to SR; 2. no inappropriate shock being delivered for asystole or SR. RESULTS: Five AEDs produced acceptable results at all levels of turbulence. Another was satisfactory for VF except at very fine amplitudes. One model was deemed unsatisfactory for in-flight use as its motion detector inhibited shocks at all levels of turbulence. CONCLUSION: Some AEDs designed primarily for ground use may not perform well under turbulent in-flight conditions. AEDs for possible in-flight or other non-terrestrial use should be fully evaluated by manufacturers or end-users before introduction to service.

Public CPR and AED Knowledge: An Opportunity for Educational Outreach in South Carolina.

OBJECTIVES: Sudden cardiac arrest (SCA) remains a significant cause of morbidity and mortality, and the key to increased survival is emergent bystander intervention. A growing body of evidence has shown that timely bystander-initiated cardiopulmonary resuscitation (CPR) and defibrillation are significantly correlated with an increased likelihood of survival. Despite these demonstrated benefits, bystanders perform these interventions in less than half of witnessed SCA cases. We hypothesized that the level of public CPR and automated external defibrillator (AED) knowledge may be limited and may play a role in the likelihood of intervening. METHODS: A convenience survey of potential bystanders to SCA was conducted in a high-traffic shopping center to estimate the overall knowledge level of CPR and AED usage and determine general attitudes toward intervening in the setting of SCA. Concurrently with the survey, professional emergency responders offered free bystander compression-only CPR and AED training on location. RESULTS: The majority of survey respondents expressed a willingness to perform the aforementioned interventions when asked directly. Results, however, indicate that although 69% of respondents consider themselves to have a general knowledge of CPR, only 18% spontaneously mentioned CPR when presented with a hypothetical SCA scenario. In addition, only 2.2% mentioned defibrillation, and 63% indicated that they would not know how to locate a public access AED when needed. Of the individuals who participated in both the survey and the training, all of them indicated that they were more likely to intervene in an SCA after receiving the training. CONCLUSIONS: Our findings suggest that future public outreach efforts should target the current CPR and AED knowledge gap. They also indicate that free, brief trainings offered at public events are a feasible way to increase the knowledge and skills of potential bystanders to SCA.

ILCOR Scientific Knowledge Gaps and Clinical Research Priorities for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care: A Consensus Statement.

Despite significant advances in the field of resuscitation science, important knowledge gaps persist. Current guidelines for resuscitation are based on the International Liaison Committee on Resuscitation 2015 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations, which includes treatment recommendations supported by the available evidence. The writing group developed this consensus statement with the goal of focusing future research by addressing the knowledge gaps identified during and after the 2015 International Liaison Committee on Resuscitation evidence evaluation process. Key publications since the 2015 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations are referenced, along with known ongoing clinical trials that are likely to affect future guidelines. © 2018 European Resuscitation Council and American Heart Association, Inc. Published by Elsevier B.V. All rights reserved.

Unusual congenital coronary artery anomaly in a young adult presenting as sudden cardiac arrest.

A previously asymptomatic young female with no previous medical or cardiac history collapsed during indoor exercise. A portable automatic external defibrillator showed a shockable rhythm. She received multiple electrical shocks with return to normal sinus rhythm without ischaemic ECG changes. Her troponin level was mildly elevated. A transthoracic echocardiogram revealed moderately reduced left ventricular ejection fraction with global hypokinesis. During emergent coronary angiography, the left main coronary artery could not be found. The right coronary artery was normal with robust collaterals to the entire left coronary circulation extending to the left main coronary artery, but did not fill the ostium. Coronary CT angiogram confirmed nearly complete absence of the left main coronary artery ostium. A diagnosis of left main coronary artery atresia was made. Patient underwent successful two vessel coronary artery bypass grafting. She continues to do well 1 year postoperatively.

Clinical Usefulness of Wearable Cardioverter Defibrillator (WCD) and Current Understanding of Its Clinical Indication in Japan.

Prevention of sudden cardiac death (SCD) has become an important issue in today's cardiovascular field, together with various developments in secondary prevention of basic cardiac diseases. The importance of the implantable cardioverter defibrillator (ICD) is now widely accepted because it has exhibited significant improvement in patients' prognoses in ischemic and non-ischemic cardiovascular diseases. However, there is an unignorable gap between the ICD indication in the guidelines and real-world high-risk patients for SCD, especially in the acute recovery phase of cardiac injury. Although various studies have demonstrated a clinical benefit of defibrillation devices, the studies of immediate ICD use in the acute recovery phase have failed to exhibit a benefit in patients from the point of the view of a decrease in total deaths. To bridge this gap, the wearable cardioverter defibrillator (WCD) provides a safer observation period in the acute phase and eliminates inappropriate overuse of ICD in the subacute phase. Here, we discuss the usefulness of the WCD and current understanding of its indications based on various clinical data. In conclusion, WCD is a feasible bridge to therapy and/or safe observation for patients at high risk of SCD, especially in the acute recovery phase of cardiac diseases.

Sensitivity and specificity of two different automated external defibrillators.

AIM: The aim was to investigate the clinical performance of two different types of automated external defibrillators (AEDs). METHODS: Three investigators reviewed 2938 rhythm analyses performed by AEDs in 240 consecutive patients (median age 72, q1-q3=62-83) who had suffered cardiac arrest between January 2011 and March 2015. Two different AEDs were used (AED A n=105, AED B n=135) in-hospital (n=91) and out-of-hospital (n=149). RESULTS: Among 194 shockable rhythms, 17 (8.8%) were not recognized by AED A, while AED B recognized 100% (n=135) of shockable episodes (sensitivity 91.2 vs 100%, p<0.01). In AED A, 8 (47.1%) of these episodes were judged to be algorithm errors while 9 (52.9%) were caused by external artifacts. Among 1039 non-shockable rhythms, AED A recommended shock in 11 (1.0%), while AED B recommended shock in 63 (4.1%) of 1523 episodes (specificity 98.9 vs 95.9, p<0.001). In AED A, 2 (18.2%) of these episodes were judged to be algorithm errors (AED B, n=40, 63.5%), while 9 (81.8%) were caused by external artifacts (AED B, n=23, 36.5%). CONCLUSIONS: There were significant differences in sensitivity and specificity between the two different AEDs. A higher sensitivity of AED B was associated with a lower specificity while a higher specificity of AED A was associated with a lower sensitivity. AED manufacturers should work to improve the algorithms. In addition, AED use should always be reviewed with a routine for giving feedback, and medical personnel should be aware of the specific strengths and shortcomings of the device they are using.

Singapore Defibrillation Guidelines 2016.

The most common initial rhythm in a sudden cardiac arrest is ventricular fibrillation or pulseless ventricular tachycardia. This is potentially treatable with defibrillation, especially if provided early. However, any delay in defibrillation will result in a decline in survival. Defibrillation requires coordination with the cardiopulmonary resuscitation component for effective resuscitation. These two components, which form the key links in the chain of survival, have to be brought to the cardiac victim in a timely fashion. An effective chain of survival is needed in both the institution and community settings.

Automated external defibrillator and operator performance in out-of-hospital cardiac arrest.

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.