Amsterdam Resuscitation Study Research Articles

Association Between Delay to First Shock and Successful First-Shock Ventricular Fibrillation Termination in Patients With Witnessed Out-of-Hospital Cardiac Arrest.

In patients with out-of-hospital cardiac arrest who present with an initial shockable rhythm, a longer delay to the first shock decreases the probability of survival, often attributed to cerebral damage. The mechanisms of this decreased survival have not yet been elucidated. Estimating the probability of successful defibrillation and other factors in relation to the time to first shock may guide prehospital care systems to implement policies that improve patient survival by decreasing time to first shock. Patients with a witnessed out-of-hospital cardiac arrest and ventricular fibrillation (VF) as an initial rhythm were included using the prospective ARREST registry (Amsterdam Resuscitation Studies). Patient and resuscitation data, including time-synchronized automated external defibrillator and manual defibrillator data, were analyzed to determine VF termination at 5 seconds after the first shock. Delay to first shock was defined as the time from initial emergency call until the first shock by any defibrillator. Outcomes were the proportion of VF termination, return of organized rhythm, transportation with return of spontaneous circulation, and survival to discharge, all in relation to the delay to first shock. A Poisson regression model with robust standard errors was used to estimate the association between delay to first shock and outcomes. Among 3723 patients, the proportion of VF termination declined from 93% when the delay to first shock was <6 minutes to 75% when that delay was >16 minutes (Ptrend<0.001). Every additional minute in VF from emergency call was associated with 6% higher probability of failure to terminate VF (adjusted relative risk, 1.06 [95% CI, 1.04-1.07]), 4% lower probability of return of organized rhythm (adjusted relative risk, 0.96 [95% CI, 0.95-0.98]), and 6% lower probability of surviving to discharge (adjusted relative risk, 0.94 [95% CI, 0.93-0.95]). Every minute of delay to first shock was associated with a significantly lower proportion of VF termination and return of organized rhythm. This may explain the worse outcomes in patients with a long delay to defibrillation. Reducing the time interval from emergency call to first shock to ≤6 minutes could be considered a key performance indicator of the chain of survival.

The association of depression and patient and resuscitation characteristics with survival after out-of-hospital cardiac arrest: a cohort study.

Out-of-hospital cardiac arrest (OHCA) is a leading cause of death worldwide, with cardiovascular disease (CVD) being a key risk factor. This study aims to investigate disparities in patient/OHCA characteristics and survival after OHCA among patients with vs. without depression. This is a retrospective cohort study using data from the AmsteRdam REsuscitation Studies (ARREST) registry from 2008 to 2018. History of comorbidities, including depression, was obtained from the patient's general practitioner. Out-of-hospital cardiac arrest survival was defined as survival at 30 days post-OHCA or hospital discharge. Logistic regression models were used to obtain crude and adjusted odds ratios (ORs) for the association between depression and OHCA survival and possible effect modification by age, sex, and comorbidities. The potential mediating effects of initial heart rhythm and provision of bystander cardiopulmonary resuscitation were explored. Among 5594 OHCA cases, 582 individuals had pre-existing depression. Patients with depression had less favourable patient and OHCA characteristics and lower odds of survival after adjustment for age, sex, and comorbidities [OR 0.65, 95% confidence interval (CI) 0.51-0.82], with similar findings by sex and age groups. The association remained significant among the Utstein comparator group (OR 0.63, 95% CI 0.45-0.89) and patients with return of spontaneous circulation (OR 0.60, 95% CI 0.42-0.85). Initial rhythm and bystander cardiopulmonary resuscitation partially mediated the observed association (by 27 and 7%, respectively). Out-of-hospital cardiac arrest patients with depression presented more frequently with unfavourable patient and OHCA characteristics and had reduced chances of survival. Further investigation into potential pathways is warranted.

Abstract 419: Incidence of True Refractory Ventricular Fibrillation in Patients Meeting a Pragmatic Definition of Refractory Ventricular Fibrillation

Introduction: Refractory VF, pragmatically defined as a shockable presenting rhythm that is still observed after three shocks and associated 2-minute CPR cycles, is often encountered in out-of-hospital cardiac arrest (OHCA) and is associated with worse outcomes. A recent clinical trial tested alternative strategies for treating patients meeting this definition of refractory VF. It is unknown how often standard defibrillation truly fails to terminate VF in these patients. Methods: Using the prospective AmsteRdam REsuscitation STudies (ARREST) registry of OHCA patients, we examined termination of VF in patients meeting the pragmatic definition of refractory VF between 2016 and 2019. All patients received standard defibrillation. We reviewed ECG waveforms from all AEDs and manual defibrillators to analyze termination of VF to a non-shockable rhythm at five seconds after each of the first 3 shocks. Refibrillation was defined as recurrence of VF after a shock terminated VF. Results: Out of 1573 OHCAs with an initial shockable rhythm, we analyzed the 453 cases (29%) that met the pragmatic definition of refractory VF. Median time to first shock was 8.0 (IQR 6.3-9.7) minutes; in 65% an AED was used. The first three shocks terminated VF at least once in 96% of the patients, at least twice in 81%, and all three times in 57%. Altogether, VF was terminated by 78% of all individual shocks. In 4% of patients all three shocks failed to terminate VF (Figure). Median time to refibrillation was 32 (IQR 12-61) seconds. ROSC at any time occurred in 59% of patients; 27% survived to discharge. Conclusions: In patients meeting a pragmatic definition of refractory VF, true refractory VF without termination of the shockable rhythm by any of the first three shocks was rare. Instead, VF was successfully terminated by most shocks and recurred during the ensuing CPR cycle. Therefore, the mechanism of benefit from alternative defibrillation strategies in these patients is unclear.

Incidence of Cardiac Arrest During Sports Among Women in the European Union

BackgroundWomen represent a growing proportion of sports participants. Still, few original data regarding sudden cardiac arrest during sports (Sr-SCA) in women are available. ObjectivesThe authors sought to assess the incidence, characteristics, and outcomes of women presenting with Sr-SCA. MethodsData were analyzed from 3 population-based European registries (ESCAPE-NET 2020 Horizon Program) that prospectively and exhaustively collect every case of SCA: SDEC (Paris-Sudden Death Expertise Center), ARREST (AmsteRdam REsuscitation Studies), and SRCR (Swedish Register for Cardiopulmonary Resuscitation). Sr-SCA was defined as SCA during or ≤1 hour after cessation of sports activity. ResultsOf 34,826 SCA between 2006 and 2017, 760 Sr-SCA (2.2%) were identified, including 54 in women. The average annual incidence of Sr-SCA in women in the 3 registries ranged from 0.10 per million (95% CI: 0.01-0.71 per million) to 0.38 per million (95% CI: 0.14-1.04 per million). Overall, the average annual incidence rate of Sr-SCA in women was 0.19 per million (95% CI: 0.14-0.24 per million), >10-fold lower compared with men (2.63 per million [95% CI: 2.45-2.83 per million]; P < 0.0001). When extrapolating to the total European population and accounting for age and sex, this yields 98 cases per year (95% CI: 72-123 cases per year) in women and 1,350 cases per year (95% CI: 1,256-1,451 cases per year) in men. Subject characteristics and circumstances of occurrence were similar in women vs men. Bystander response, time to defibrillation, and survival rate at hospital admission (58.8% vs 58.5%; P = 0.99) and 30 days did not differ significantly between women and men. ConclusionsThese findings emphasize the dramatically lower risk of Sr-SCA in women compared with men, despite similar subject characteristics. This should be considered in designing preparticipation screening strategies in the future.

Manual chest compression pause duration for ventilations during prehospital advanced life support – An observational study to explore optimal ventilation pause duration for mechanical chest compression devices

AimMechanical chest compression devices in the 30:2 mode generally provide a pause of three seconds to give two insufflations without evidence supporting this pause duration. We aimed to explore the optimal pause duration by measuring the time needed for two insufflations, during advanced life support with manual compressions. MethodsProspectively collected data in the AmsteRdam REsuscitation STudies (ARREST) registry were analysed, including thoracic impedance signal and waveform capnography from manual defibrillators of the Amsterdam ambulance service. Compression pauses were analysed for number of insufflations, time interval from start of the compression pause to the end of the second insufflation, chest compression pause duration and ventilation subintervals. ResultsDuring 132 out-of-hospital cardiac arrests, 1619 manual chest compression pauses to ventilate were identified. In 1364 (84%) pauses, two insufflations were given. In 28% of these pauses, giving two insufflations took more than three seconds. The second insufflation is completed within 3.8 seconds in 90% and within 5 seconds in 97.5% of these pauses. An increasing likelihood of achieving two insufflations is seen with increasing compression pause duration up to five seconds. ConclusionThe optimal chest compression pause duration for mechanical chest compression devices in the 30:2 mode to provide two insufflations, appears to be five seconds, warranting further studies in the context of mechanical chest compression. A 5-second pause will allow providers to give two insufflations with a very high success rate. In addition, a 5-second pause can also be used for other interventions like rhythm checks and endotracheal intubation.

Temporal variation in out-of-hospital cardiac arrest occurrence in individuals with or without diabetes

ObjectiveOut-of-hospital cardiac arrest (OHCA) occurrence has been shown to exhibit a circadian rhythm, following the circadian rhythm of acute myocardial infarction (AMI) occurrence. Diabetes mellitus (DM) is associated with changes in circadian rhythm. We aimed to compare the temporal variation of OHCA occurrence over the day and week between OHCA patients with DM and those without. MethodsIn two population-based OHCA registries (Amsterdam Resuscitation Studies [ARREST] 2010–2016, n = 4163, and Danish Cardiac Arrest Registry [DANCAR], 2010–2014, n = 12,734), adults (≥18y) with presumed cardiac cause of OHCA and available medical history were included. Single and double cosinor analysis was performed to model circadian variation of OHCA occurrence. Stratified analysis of circadian variation was performed in patients with AMI as immediate cause of OHCA. ResultsDM patients (22.8% in ARREST, 24.2% in DANCAR) were older and more frequently had cardiovascular risk factors or previous cardiovascular disease. Both cohorts showed 24 h-rhythmicity, with significant amplitudes in single and double cosinor functions (P-range < 0.001). In both registries, a morning peak (10:00–11:00) and an evening peak (20:00–21:00) was observed in both DM and non-DM patients. No septadian variation was observed in either DM or non-DM patients (P-range 0.13–84). ConclusionsIn these two population-based OHCA registries, we observed a similar circadian rhythm of OHCA occurrence in DM and non-DM patients.

To transport or to terminate resuscitation on-site. What factors influence EMS decisions in patients without ROSC? A mixed-methods study

BackgroundIf a patient in out-of-hospital cardiac arrest (OHCA) does not achieve return of spontaneous circulation (ROSC) despite advanced life support, emergency medical services can decide to either transport the patient with ongoing CPR or terminate resuscitation on scene. PurposeTo determine differences between patients without ROSC to be transported vs. terminated on scene and explore medical and nonmedical factors that contribute to the decision-making of paramedics on scene. MethodsMixed-methods approach combining quantitative and qualitative data. Quantitative data on all-cause OHCA patients without ROSC on scene, between January 1, 2012, and December 31, 2016, in the Amsterdam Resuscitation Study database, were analyzed to find factors associated with decision to transport. Qualitative data was collected by performing 16 semi-structured interviews with paramedics from the study region, transcribed and coded to identify themes regarding OHCA decision-making on the scene. ResultsIn the quantitative Utstein dataset, of 5870 OHCA patients, 3190 (54%) patients did not achieve ROSC on scene. In a multivariable model, age (OR 0.98), public location (OR 2.70), bystander witnessed (OR 1.65), EMS witnessed (OR 9.03), and first rhythm VF/VT (OR 11.22) or PEA (OR 2.34), were independently associated with transport with ongoing CPR. The proportion of variance explained by the model was only 0.36. With the qualitative method, four main themes were identified: patient-related factors, local circumstances, paramedic-related factors, and the structure of the organization. ConclusionIn patients without ROSC on scene, besides known resuscitation characteristics, the decision to transport a patient is largely determined by non-protocollized factors.

Time to Return of Spontaneous Circulation and Survival: When to Transport in out-of-Hospital Cardiac Arrest?

Background In out-of-hospital cardiac arrest (OHCA), 10–50% of patients have return of spontaneous circulation (ROSC) before hospital arrival. It is important to investigate the relation between time-to-ROSC and survival to determine the optimal timing of transport to the hospital in patients without ROSC. Methods: We analyzed data of OHCA patients with a presumed cardiac cause (excluding traumatic and other obvious non-cardiac causes) and ROSC before hospital arrival from the Amsterdam Resuscitation Study (ARREST) database. ROSC included those patients whose ROSC was persistent or transient before or during transport, lasting ≥1 min. Of these data, we analyzed the association between the time of emergency medical services (EMS) arrival until ROSC (time-to-ROSC) and 30-day survival. Results: Of 3632 OHCA patients with attempted resuscitation, 810 patients with prehospital ROSC were included. Of these, 332 (41%) survived 30 days. Survivors had a significant shorter time-to-ROSC compared to non-survivors of median 5 min (IQR 2,10) vs. median 12 min (IQR 9,17) (p < 0.001). Of the survivors, 90% achieved ROSC within 15 min compared to 22 min of non-survivors. In a multivariable model adjusted for known system determinants time-to-ROSC per minute was significantly associated with 30-day survival (OR 0.89; 95%CI 0.86–0.91). A ROC curve showed 8 min as the time-to-ROSC with the best test performance (sensitivity of 0.72 and specificity of 0.77). Conclusion: In OHCA patients with prehospital ROSC survival significantly decreases with increasing time-to-ROSC. Of all patients, 90% of survivors had achieved ROSC within the first 15 min of EMS resuscitation. The optimal time for the decision to transport is between 8 and 15 min after EMS arrival.

Transfer of essential AED information to treating hospital (TREAT)

BackgroundDefibrillation in out-of-hospital cardiac arrest (OHCA) is increasingly performed by using an Automated External Defibrillator (AED). Therefore presence of a shockable rhythm is recurrently only documented by the AED. However, AED-information is rarely available to the treating physician. PurposeTo determine (1) how often a shockable rhythm was recorded only in the AED; (2) if so, how often information that a shockable rhythm had been present reached the physician. MethodsData on OHCA patients with (presumed) cardiac cause with an AED connected in the years 2012–2014 (Study period 1) and 2016 (Study period 2) in the Amsterdam Resuscitation Study (ARREST) database were collected. We determined how often only the AED had defibrillated. In these patients, we retrospectively analyzed EMS run sheets and hospital discharge letters to determine if a shockable rhythm and/or AED use was correctly noted. In Study period 2, we prospectively contacted the physicians to study whether AED defibrillation was known. ResultsIn Study period 1, of 2840 OHCA CPR attempts with (presumed) cardiac cause, 1521 (54%) patients had a shockable rhythm, with 356 patients (13%) receiving AED defibrillation only. Of these patients, 11 hospital discharge letters (4%) contained no information about a shockable rhythm. In Study period 2, 125/1128 patients (11%) received AED defibrillation only; of these, in two cases the shockable rhythm was unknown by the physician. ConclusionIn 11–13% of OHCAs, a shockable rhythm is only seen on the AED-ECG. Adequate transfer to the physician of vital AED-information is essential but not always accomplished.

Time of on-scene resuscitation in out of-hospital cardiac arrest patients transported without return of spontaneous circulation

BackgroundIn out-of-hospital cardiac arrest (OHCA), return of spontaneous circulation (ROSC) on scene occurs only in a minority of patients. The optimal duration of resuscitation on scene before transport with ongoing cardiopulmonary resuscitation (CPR) is unknown. PurposeTo determine the time of resuscitation on scene (‘time on scene’) and survival in patients transported with ongoing CPR in the Netherlands. MethodsData on OHCA patients (>18 years) without ROSC on scene, where resuscitation was started between January 1, 2012 and December 31, 2016 in the Amsterdam Resuscitation Study (ARREST) database were analyzed. Time on scene was related to 30-day survival. ResultsOf the 5871 OHCA patients where resuscitation was started, 2437 did not achieve ROSC on scene. Of these, 655 patients were transported with ongoing CPR and 606 (93%) had complete rhythm data. At the moment of transport, 199 (33%) patients had a shockable rhythm, 299 (49%) pulseless electrical activity (PEA) and 108 (18%) asystole as rhythm. Twenty-nine patients (4%) were alive at 30 days. Patients who survived 30 days had a higher proportion of a shockable first monitored rhythm (89% vs. 52%, p < 0.001). Survivors had a significantly shorter time on scene (20 min vs. 26 min, p = 0.004), with the highest survival rate (8%) in patients transported within 20 min. In a multivariable model time on scene (OR 0.94; 95%CI 0.89–0.99) was independently associated with 30-day survival. ConclusionIn OHCA patients transported with ongoing CPR the survival rate significantly declines when time on scene increases.

Abstract 172: Initial Rhythm and Rhythm at Moment of Transport Related to Survival in Potential ECPR Patients in the Netherlands

Purpose: Extracorporeal cardiopulmonary resuscitation (ECPR) shows promising results in patients found in ventricular fibrillation (VF) without return of spontanous circulation (ROSC) on scene. Insight in rhythm at moment of transport and survival of potential ECPR patients could help to identify which patients should be transported for ECPR. Methods: Data of potential ECPR patients (shockable first rhythm, witnessed arrest, bystander CPR and age 18-70 year) transported without ROSC between 2012 and 2016 in the Amsterdam Resuscitation Study (ARREST) database were analyzed. Initial rhythm and rhythm at moment of transport was related to 30-day survival. Results: Of 5872 OHCA patients with attempted resuscitation, 649 (11%) were transported with ongoing CPR. Of these, 162 (25%) were considered potential ECPR patients and 153 cases with complete data were analysed. Thirteen of these 153 patients (9%) were alive at 30 days. At start of transport, 68 patients (44%) had VF/VT, 58 (38%) PEA and 27 (18%) asystole. Of these, 10, 2 and 1 patients survived, respectively (figure). 30-day survival of patients with a shockable rhythm at start of transport was significantly higher compared to non-shockable rhythms (15% vs 3%, p=0.014). During transport 10 of 153 patients (7%) achieved ROSC, and 3 patients (30%) survived. VF/VT at start of transport identified 10/13 (77%) of all survivors. In patients without ROSC at hospital arrival, VF/VT also resulted in the highest survival (13%). Conclusion: In ECPR candidate patients, a shockable rhythm at the moment of transport (44%) identified 77% of patients surviving 30 days.

Abstract 18: Analyzing Heart Rhythm During Chest Compressions in Out-of-Hospital Cardiac Arrest Patients Using New Algorithm for Automated External Defibrillators

Purpose: Automated external defibrillators (AED) prompt the rescuer to stop cardiopulmonary resuscitation (CPR) for ECG analysis. Any interruption of CPR has a negative impact on outcome. We prospectively evaluated a new algorithm (cprINSIGHT) which can analyse the ECG while rescuers continue CPR. Methods: We analysed data from patients with attempted resuscitation from OHCA who were connected to an AED with cprINSIGHT (Stryker Physio-Control LIFEPAK CR2) between June 2017 and June 2018 in the Amsterdam Resuscitation Study region. The first analysis in the CR2 is a conventional analysis; subsequent analyses use the cprINSIGHT algorithm. This algorithm classifies the rhythm as shockable (S), non-shockable (NS), or no decision. If no decision, the AED prompts for a pause in CPR and uses its conventional algorithm. The characteristics of the first 3 cprINSIGHT analyses (analyses 2-4) were analysed. Ventricular fibrillation (VF) cases were both coarse and fine VF with a lower threshold of 0.08 mV. Results: Data from 132 consecutive OHCA cases were analysed. The initial recorded rhythm was VF or pulseless ventricular tachycardia (VT) in 35 cases (27%), pulseless electrical activity in 34 cases (25%) and asystole in 63 cases (48%). In 114 cases (86%), 1 or more cprINSIGHT analyses were done. Analyses 2-4 covered 90% of all cprINSIGHT analyses. The analyzed rhythm was VF/VT in 12-17%, organised QRS rhythm in 29-35% and asystole in 51-56% (see table). cprINSIGHT reached a S or NS decision in 65-74% of cases, with a sensitivity of 90-100% and a specificity of 100%. When it reached no decision, the rhythm was asystole in 65-79% of analyses, VF/VT in 0-9% and QRS rhythm in 18-27%; conventional analysis followed. Chest compression fraction was 85-88%, CPR fraction was 99%. Conclusion: This new algorithm analysed the ECG without need for a pause in chest compressions 65-74% of the time and had 90-100% sensitivity and 100% specificity when it made a shock or a no shock decision.

Non-steroidal anti-inflammatory drugs and the risk of out-of-hospital cardiac arrest: a case-control study.

AimsNon-steroidal anti-inflammatory drugs (NSAIDs), particularly selective COX-2 inhibitors, are associated with an increased risk of cardiovascular adverse events. However, the association between these drugs and out-of-hospital cardiac arrest with electrocardiogram-documented ventricular tachycardia/ventricular fibrillation (VT/VF-OHCA) has not been studied yet. This study was aimed to evaluate the association between the use of selective COX-2 inhibitors or conventional NSAIDs and VT/VF-OHCA compared with non-use.Methods and resultsA case–control study was conducted among 2483 cases with VT/VF-OHCA from the AmsteRdam REsuscitation STudies (ARREST) registry, an ongoing Dutch registry of OHCA, and 10 441 non-VT/VF-OHCA-controls from the Dutch PHARMO Database Network, containing drug dispensing records of community pharmacies, over the period July 2005–December 2011. Up to five controls were matched for age and sex to one case at the date of VT/VF-OHCA (index date). Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by conditional logistic regression analysis. Of the cases, 0.5% was currently exposed at the index date to selective COX-2 inhibitors and 2.5% to conventional NSAIDs. Neither current use of selective COX-2 inhibitors nor conventional NSAIDs were associated with an increased risk of VT/VF-OHCA (adjusted OR 1.11, 95% CI: 0.79–1.56 and adjusted OR 0.97, 95% CI: 0.86–1.10, respectively) compared with non-use. Stratification for VT/VF-OHCA with presence/absence of acute myocardial infarction did not change these results.ConclusionExposure to selective COX-2 inhibitors or conventional NSAIDs was not associated with an increased risk of VT/VF-OHCA compared with non-use.

The impact of serum potassium‐influencing antihypertensive drugs on the risk of out‐of‐hospital cardiac arrest: A case–control study

Sudden cardiac arrest (SCA) is a complex multifactorial event and most commonly caused by ventricular tachycardia/ fibrillation (VT/ VF). Some antihypertensive drugs could induce hypokalaemia or hyperkalaemia, which may increase susceptibility to VT/VF and SCA. To assess the association between different classes of antihypertensive drugs classified according to their potential impact on serum potassium levels and the occurrence of out-of-hospital cardiac arrest (OHCA) based on VT/VF. A case-control study was performed among current users of antihypertensive drugs. Cases were OHCA victims with electrocardiogram documented VT/VF drawn from the AmsteRdam REsuscitation STudies (ARREST) registry, and controls were non-OHCA individuals from the PHARMO database. Antihypertensive drugs were classified into: (i) antihypertensives with neutral effect on serum potassium levels; (ii) hypokalaemia-inducing antihypertensives; (iii) hyperkalaemia-inducing antihypertensives; (iv) combination of antihypertensives with hypo- and hyperkalaemic effects. We included 1345 cases and 4145 controls. The risk of OHCA was significantly increased among users of hypokalaemia-inducing antihypertensives [adjusted odds ratio (OR) 1.39; 95% confidence interval (CI) 1.10-1.76] and among users of a combination of antihypertensives with hypo- and hyperkalaemic effects (adjusted OR 1.42; 95%CI 1.17-1.72) vs. users of antihypertensives with neutral effect. There was no difference in OHCA risk between users of hyperkalaemia-inducing antihypertensives vs. users of antihypertensive drugs with neutral effect (adjusted OR 1.15; 95%CI 0.95-1.40). The risk of OHCA is significantly increased in patients who were current users of hypokalaemia-inducing antihypertensives and patients using a combination of antihypertensives with hypo- and hyperkalaemic effects.

Sudden Cardiac Arrest and Rare Genetic Variants in the Community.

Sudden cardiac arrest (SCA) ranks among the most common causes of death worldwide. Because SCA is most often lethal, yet mostly occurs in individuals without previously known cardiac disease, the identification of patients at risk for SCA could save many lives. In unselected SCA victims from the community, common genetic variants (which are not disease-causing per se, but may increase susceptibility to ventricular fibrillation) are found to be associated with increased SCA risk. However, whether rare genetic variants contribute to SCA risk in the community is largely unexplored. We here investigated the involvement of rare genetic variants in SCA risk at the population level by studying the prevalence of 6 founder genetic variants present in the Dutch population (PLN-p.Arg14del, MYBPC3-p.Trp792fsX17, MYBPC3-p.Arg943X, MYBPC3-p.Pro955fsX95, PKP2-p.Arg79X, and the Chr7q36 idiopathic ventricular fibrillation risk haplotype) in a cohort of 1440 unselected Dutch SCA victims included in the Amsterdam Resuscitation Study (ARREST). The six studied founder mutations were found to be more prevalent (1.1%) in the ARREST SCA cohort compared with an ethnically and geographically matched set of controls (0.4%, n=1379; P<0.05) or a set of Dutch individuals drawn from the Genome of the Netherlands (GoNL) study (0%, n=500; P<0.02). This finding provides proof-of-concept for the notion that rare genetic variants contribute to some extent to SCA risk in the community.

Causes for the declining proportion of ventricular fibrillation in out-of-hospital cardiac arrest

AimsThe reported proportion of ventricular fibrillation (VF) in out-of-hospital cardiac arrest (OHCA) has declined worldwide. VF decline may be caused by less VF at collapse and/or faster dissolution of VF into asystole. We aimed to determine the causes of VF decline by comparing VF proportions in relation to delay from emergency medical services (EMS) call to initial ECG (call-to-ECG delay), and VF dissolution rates between two study periods. MethodsData from the AmsteRdam REsuscitation STudies (ARREST), an ongoing OHCA registry in the Netherlands, were used. We studied cardiac OHCA in the study periods 1995–1997 (n=917) and 2006–2012 (n=5695). Cases with available ECG and information on call-to-ECG delay were included. We tested whether initial VF proportion and VF dissolution rates differed between both study periods using logistic regression. ResultsDespite a 15% VF decline between the periods, VF proportion around EMS call remained high in 2006–2012 (64%). The odds ratio (OR) for VF proportion in 2006–2012 vs. 1995–1997 was 0.52 (95%-CI 0.45–0.60, P<0.001), with similar rates of VF dissolution in both periods (P=0.83). VF decline was higher for unwitnessed collapse (OR 0.41, 95%-CI 0.28–0.58) and collapse at home (OR 0.50, 95%-CI 0.42–0.59), but not for categories of bystander CPR, age or sex. ConclusionVF proportion early after collapse remains high. VF decline is explained by the occurrence of less initial VF, rather than faster dissolving VF. An increase in unwitnessed OHCA and collapse at home contributes to the observed VF decline.

Abstract 152: Impact of Shock Timing During Mechanical CPR on Defibrillation Efficacy

Background: Mechanical CPR (mCPR) devices enable defibrillation shock delivery during ongoing chest compressions, without the pause required during manual CPR. It is unknown whether shock delivery during ongoing mCPR, vs. during a pause, affects VF termination efficacy. Animal studies suggest that during ongoing mCPR, timing a shock to a specific phase of the compression cycle may significantly affect shock efficacy. Methods: We retrospectively analyzed electronic defibrillator recordings from the Amsterdam Resuscitation Study (ARREST), a prospective out-of-hospital cardiac arrest registry. We identified cases with LUCAS mCPR and at least one shock delivered after mCPR initiation. Shocks were sorted by energy level, and the most prevalent (360 J) was selected for the present analysis. Continuous ECG and impedance signals were analyzed to determine VF termination (defined as absence of VF at 5 sec after shock) for each shock after mCPR initiation, and whether the shock was delivered during a pause or during mCPR. For shocks delivered during a pause we measured pre-shock pause duration; for shocks delivered without pausing we measured the exact timing of the shock during the compression cycle. Results: In 153 cases meeting analysis criteria, 509 360J shocks occurred after mCPR initiation; VF termination outcome could be determined for 460. VF termination for first eligible shock during mCPR in each case was 84/97 (87%) during a pause, and 79/93 (85%; p=0.74) during ongoing mCPR; for all eligible shocks, VF termination was 203/242 (83.9%) and 155/196 (79.1%; p=0.20) respectively. For shocks during mCPR, there were no statistically significant differences in VF termination rate for shocks during four equal length phases beginning with LUCAS piston upstroke: 39/44 (89%), 39/49 (80%), 35/51 (69%), 40/50 (80%) (p = 0.12). For shocks during a pause, VF termination rate did not differ for pre-shock pauses ≤5 sec (75/91, 82.4%) vs. &gt;5 sec (128/151, 84.8%; p=0.63). Conclusions: Our results indicate that shocks can be delivered during ongoing mCPR without reducing defibrillation efficacy. The exact shock timing during the mCPR compression cycle did not significantly alter shock efficacy. VF termination rate was not affected by pre-shock pause duration during mCPR.

Genetic, clinical and pharmacological determinants of out-of-hospital cardiac arrest: rationale and outline of the AmsteRdam Resuscitation Studies (ARREST) registry

IntroductionOut-of-hospital cardiac arrest (OHCA) is a major public health problem. Recognising the complexity of the underlying causes of OHCA in the community, we aimed to establish the clinical, pharmacological, environmental...

Most Important Outcomes Research Papers on Device Therapies for Cardiomyopathies

Disorders of the cardiac muscle or cardiomyopathies are a broad, yet collectively common, group of conditions. Despite the heterogeneous etiologies, mode of death from these conditions is remarkably similar - progressive decline in cardiac function leading to intractable heart failure (HF) and sustained ventricular arrhythmias resulting in sudden cardiac death (SCD). Nearly 50% of patients die within 5 years of a HF diagnosis.1 Indeed, in the United States, HF alone is thought to cause 55,000 deaths per year2 and further contribute to 1 in 9 deaths overall.1 However, while advanced HF and the risk of SCD were once thought to be untreatable, technological advances has seen the emergence of device therapies as viable treatment options. Specifically, implantable cardioverter-defibrillator (ICD) therapy for treatment of ventricular arrhythmias, cardiac resynchronization therapy (CRT) for restoring cardiac synchrony and mechanical efficiency, and ventricular assist device (VAD) therapy to temporarily or permanently replace the function of the failing heart, have all emerged as highly efficacious therapies. The expanding use of device therapies, however, poses many challenges. First, while the indications for these devices are well summarized in clinical guidelines,3,4 considerable hurdles remain in ensuring eligible patients receive these therapies.5 By the same token, establishing the safety and effectiveness of these therapies in populations that are found in clinical practice, yet commonly excluded from trials, such as the elderly6 and uncommon forms of cardiomyopathies,7 is a high priority. Second, rapid dissemination of technologies frequently results in disparities in care. Indeed, age, gender, and racial disparities, in both receipt of these devices and outcomes following implantation, have been well documented. Whether these disparities have persisted, and the potential causative mechanisms underlying these disparities, however, are uncertain.8,9 Third, these devices are not without significant untoward effects; understanding …

Epilepsy is a risk factor for sudden cardiac arrest in the general population.

BackgroundPeople with epilepsy are at increased risk for sudden death. The most prevalent cause of sudden death in the general population is sudden cardiac arrest (SCA) due to ventricular fibrillation (VF). SCA may contribute to the increased incidence of sudden death in people with epilepsy. We assessed whether the risk for SCA is increased in epilepsy by determining the risk for SCA among people with active epilepsy in a community-based study.Methods and ResultsThis investigation was part of the Amsterdam Resuscitation Studies (ARREST) in the Netherlands. It was designed to assess SCA risk in the general population. All SCA cases in the study area were identified and matched to controls (by age, sex, and SCA date). A diagnosis of active epilepsy was ascertained in all cases and controls. Relative risk for SCA was estimated by calculating the adjusted odds ratios using conditional logistic regression (adjustment was made for known risk factors for SCA). We identified 1019 cases of SCA with ECG-documented VF, and matched them to 2834 controls. There were 12 people with active epilepsy among cases and 12 among controls. Epilepsy was associated with a three-fold increased risk for SCA (adjusted OR 2.9 [95%CI 1.1–8.0.], p = 0.034). The risk for SCA in epilepsy was particularly increased in young and females.ConclusionEpilepsy in the general population seems to be associated with an increased risk for SCA.