Abstract 9764: Prevalence of Inappropriate Defibrillation Attempts During Pediatric In-Hospital Cardiac Arrest

Introduction: Shockable rhythms (ventricular fibrillation [VF] and ventricular tachycardia [VT]) occur in <25% of pediatric in-hospital cardiac arrest (IHCA) events, yet the prevalence of inappropriate defibrillation attempts for non-VF/VT rhythms is unknown. We aim to describe the prevalence of inappropriate shocks across a large, multi-national pediatric cardiac arrest network. Methods: We included children <18y reported to the pedi atric RES uscitation- Q uality (pediRES-Q) network from 2015-2019 with complete defibrillator files who received defibrillation attempts during IHCA (ZOLL R-Series, MA). Two pediatric cardiologists independently classified rhythms immediately prior to shock as: 1) appropriate (VF or wide complex ≥ 150/min), 2) indeterminate (narrow complex ≥150/min or wide complex 100-149/min), or 3) inappropriate (asystole, sinus, narrow complex <150/min, or wide complex <100/min). Rhythms that were undecipherable due to artifact were excluded from analysis (n=22). Disagreements were resolved by arbitration and consensus. Results: Of 896 IHCA events, 124 (14%) had defibrillation attempts. A total of 303 shocks were delivered: 87 (29%) in age <1y, 84 (28%) in 1-8y, and 132 (44%) in 9-17y. Of shocks delivered, 206 (68%) were appropriate, 12 (4%) indeterminate, and 85 (28%) inappropriate. There was no difference in inappropriate shock delivery by age category: <1y (24/87, 28%), 1-8y (26/84, 31%), 9-17y (35/132, 27%) ( p =0.4). Conclusions: Across a multi-national pediatric cardiac arrest network, a large proportion (28%) of defibrillation attempts were inappropriate, suggesting significant opportunity for improvement in rhythm identification in pediatric cardiac arrest. There was no difference in inappropriate shock delivery across age groups. Figure 1. Representation of rhythm classification and appropriateness of defibrillation attempts with exemplar rhythms.

Abstract 10911: Amplitude Spectral Area to Guide Shock and Epinephrine Delivery in a Swine Model of Ventricular Fibrillation and Closed-Chest Resuscitation

Introduction: VF accounts for ~30% of all sudden cardiac arrest episodes. VF signal analysis in the frequency domain - calculating the amplitude spectral area (AMSA) - can inform on the probability that an electrical shock could terminate VF followed by return of spontaneous circulation (ROSC). BLS guidelines require delivery of shocks every 2 min and epinephrine every 4 min. Yet, shocks often do not terminate VF and may injure the myocardium. We have previously reported that guiding the timing of shock delivery based on AMSA reduces myocardial injury and improves outcome. Epinephrine is given to increase the coronary perfusion pressure (CPP) and therefore myocardial blood flow but has detrimental effects on post-resuscitation myocardial function and possibly on neurological outcome. Hypothesis: Monitoring AMSA during CPR could be used not only to guide shock delivery but also to avoid administering epinephrine when AMSA predicts a high probability of shock success, reserving epinephrine when AMSA predicts a low probability of shock success and additional CPP increase might be helpful. Methods: In a swine model of electrically induced VF and mechanical chest compressions, two resuscitation protocols were compared in 8 pigs each: (1) A guidelines-driven (GD), delivering shocks and epinephrine guided by the current BLS protocol and (2) An AMSA-driven, delivering shocks and epinephrine guided by AMSA (ADSE). VF was untreated for 10 min and pigs that achieved ROSC were monitored for 240 min. Results: Compared to GD, ADSE was associated with a shorter time to ROSC (400±80 vs 569±16 sec, p=0.034) and higher survival rate at 240 minutes with borderline statistical significance (7/8 vs 3/8, p=0.059). ADSE required fewer shocks (3±2 vs 5±2, p=0.026) and received fewer doses of epinephrine (median [interquartile range], 1[1-1] vs 2[1.3-3], p=0.038). Conclusions: Resuscitation with the ADSE protocol was superior to the GD protocol resulting in a shorter time to ROSC with improved survival requiring fewer shocks and fewer epinephrine doses. The ADSE protocol represents a more tailored approach to resuscitation enabling delivery of resuscitation interventions with higher precision and consequently minimizing their associated adverse effects.

Location-dependent threat and associated neural abnormalities in clinical anxiety

Anxiety disorders are characterized by maladaptive defensive responses to distal or uncertain threats. Elucidating neural mechanisms of anxiety is essential to understand the development and maintenance of anxiety disorders. In fMRI, patients with pathological anxiety (ANX, n = 23) and healthy controls (HC, n = 28) completed a contextual threat learning paradigm in which they picked flowers in a virtual environment comprising a danger zone in which flowers were paired with shock and a safe zone (no shock). ANX compared with HC showed 1) decreased ventromedial prefrontal cortex and anterior hippocampus activation during the task, particularly in the safe zone, 2) increased insula and dorsomedial prefrontal cortex activation during the task, particularly in the danger zone, and 3) increased amygdala and midbrain/periaqueductal gray activation in the danger zone prior to potential shock delivery. Findings suggest that ANX engage brain areas differently to modulate context-appropriate emotional responses when learning to discriminate cues within an environment.

Is there an antiarrhythmic benefit from switching to sacubitril/valsartan therapy? A systematic review and meta-analysis

Background Sacubitril/valsartan through reverse structural remodeling and neurohormonal inhibition could play an antiarrhythmic role. Purpose This systematic review and meta-analysis was performed to explore the arrhythmiologic effects of switching patients with heart failure with reduced ejection fraction (HFrEF) from angiotensin converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARBs) to sacubitril/valsartan. Methods We searched major databases for studies comparing device-detected, incident atrial and ventricular arrhythmias in patients with HFrEF while on ACEi/ARBs versus while on sacubitril/valsartan. For pooling the primary outcome of interest, we calculated the risk difference (RD) with the corresponding 95% confidence interval (CI) in the probability of experiencing each arrhythmic event while on ACEi/ARBs and while on sacubitril/valsartan. A random effects (DerSimonian-Laird) model was adopted. Results We analyzed 4 eligible studies, resulting in 497 patients with a pooled mean age of 67.8±10.36. 64% had ischemic cardiomyopathy while 98% had either an implantable cardioverter defribrillator or a cardiac resynchronization therapy device. Main comorbidities were hypertension (68.7%) and dyslipidemia (59.6%). Almost all (96.3%) patients were treated with b-blockers and 23.7% were also receiving anti-arrhythmic drugs, mainly amiodarone. After switching to sacubitril/valsartan there was a trend towards reduced risk for sustained ventricular tachycardia/fibrillation and non-sustained ventricular tachycardias (RD: −0.04, 95% CI: −0.09–0.02, I2: 65.7% and −0.06, 95% CI: −0.19–0.07, I2: 85%; respectively). Meta-regression analysis showed that patients with ischemic cardiomyopathy experience greater benefit. Incident paroxysmal atrial fibrillation/tachycardia was significantly reduced (RD: −0.09 95% CI: −0.14 to −0.03, I2: 0%), while favorable effects were noticed for the risk of appropriate shock delivery and inadequate biventricular pacing (RD: −0.06, 95% CI: −0.09 to −0.03, I2: 0% and −0.06, 95% CI: −0.11 to 0.00, I2: 35.55%, respectively). All results seem to suffer from publication bias. Conclusion Limited data support that switching to sacubitril/valsartan seems to be associated with reduced risk for both ventricular and atrial arrhythmias. More studies are needed to clarify the potential anti-arrhythmic role of this drug. Whether patients with frequent arrhythmias or at high arrhythmic risk may benefit from early switch is a matter of further investigation. FUNDunding Acknowledgement Type of funding sources: None. Figure 1 Figure 2

Inappropriate shock delivery by an implantable cardioverter-defibrillator due to electrical interference with a refrigerator in a 4-year-old child

We report a patient with long QT syndrome who received an inappropriate implantable cardioverter-defibrillator shock due to electrical interference from a refrigerator. This electrical interference was mistakenly detected as an episode of ventricular fibrillation and ended with an inappropriate delivery of shock without any warning symptoms before.

The efficacy of using Google Maps in accessing nearby public automated external defibrillators in Thailand

Introduction Early defibrillation remains the highest priority in the chain of survival for out-of-hospital cardiac arrest. Shock delivery should be performed within 5 minutes of collapse to achieve a 50% survival rate. Google Maps has been one of the most popular mobile navigation applications worldwide. Our primary objective was to assess the efficacy of Google Maps in locating nearby public automated external defibrillators (AEDs). Methods Local and non-local populations were enrolled. Participants were randomly assigned to locate AEDs with or without the assistance of Google Maps. Participants used Google Maps on the same smartphone and cellular data network, an activity tracker recorded data for distance covered and time required to retrieve the AED. AEDs were located within 150 seconds of the starting point. Results Out of 100 recruited participants there was no difference in baseline characteristics. In the local population group, Google Maps assistance did not show statistical significance in successfully locating the AED within 150 seconds. Correspondingly, the travel time also showed no difference (173.52 ± 50.99 seconds for Google Maps vs. 206.20 ± 159.53 seconds for control group). The result in the non-local population group revealed no significant difference in successfully locating AEDs within 150 seconds: Google Maps (18.52%) vs. control group (39.13%); p=0.126. The recorded travel time between the Google Maps group and control group were similar (307.59 ± 220.10 seconds vs. 284.0 ± 222.37 seconds; p=0.709). Conclusion In Thailand, using Google Maps mobile assistance was found to be unhelpful in accessing nearby public AEDs.

Association of subsequent shock after conversion to shockable rhythm with outcomes stratified by the type of initial non-shockable rhythm in children with out-of-hospital cardiac arrest

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The Japan Society for the Promotion of Science (Grant-in-Aid for Scientific Research) Background/Introduction: The rhythm conversion from initial non-shockable to shockable rhythm during cardiopulmonary resuscitation (CPR) by emergency medical services (EMS) providers may be associated with neurologically intact survival after out-of-hospital cardiac arrest (OHCA) in children with an initial non-shockable rhythm. However, the prognostic significance of rhythm conversion stratified by the type of initial non-shockable rhythm is still unclear. Purpose We aimed to investigate the association of subsequent shock after rhythm conversion to shockable rhythm with neurologically intact survival and shock delivery time (time from EMS-initiated CPR to first shock delivery) by the type of initial non-shockable rhythm in children with OHCA. Methods We analysed the records of 19,095 children (age &lt;18 years) with OHCA treated by EMS providers. Data were obtained from a prospectively recorded Japanese nationwide Utstein-style database for a 13-year period (2005–2017). The primary outcome measure was 1-month neurologically intact survival, defined as cerebral performance category score of 1 to 2. Patients were divided into the initial pulseless electrical activity (PEA) (n = 3,326 [17.4%]) and initial asystole (n = 15,769 [82.6%]) groups. Results The proportion of patients who received subsequent shock after conversion to shockable rhythm was significantly higher in the initial PEA than in the initial asystole groups (3.3% [109/3,326] vs. 1.4% [227/15,769], p &lt; 0.0001). The shock delivery time was significantly shorter in the initial PEA than in the initial asystole groups (median [IQR], 8 min [5 min – 12 min] vs. 10 min [6 min – 16 min], p &lt; 0.01). Among the initial PEA patients, there was no significant difference between subsequently shocked (10.0% [11/109]) and subsequently non-shocked patients (6.0% [192/3,217], p = 0.10) regarding the rate of 1-month neurologically intact survival. However, after adjusting for 9 pre-hospital variables, subsequent shock with a delivery time of &lt;10 min was associated with increased odds of neurologically intact survival compared with no shock delivery (adjusted odds ratio [OR], 2.45; 95% confidence interval [CI], 1.16–5.16], p = 0.018). Among the initial asystole patients, the rate of 1-month neurologically intact survival was significantly higher in the subsequently shocked (4.4% [10/227]) than in the subsequently non-shocked (0.7% [106/15,542], p &lt; 0.0001). A multivariate logistic regression model showed that subsequent shock with a delivery time of &lt;10 min was associated with increased odds of neurologically intact survival compared with no shock delivery (adjusted OR, 9.77 [95% CI, 4.2–22.5], p &lt; 0.0001). Conclusions In children with OHCA with an initial non-shockable rhythm, subsequent shock after conversion to shockable rhythm during CPR was associated with increased odds of 1-month neurologically intact survival only when shock was delivered &lt;10 min from EMS-initiated CPR regardless of the type of initial rhythm.

Subsequent shock delivery and outcomes in out-of-hospital cardiac arrests with initial unshockable rhythm

Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): The Japan Society for the Promotion of Science (Grant-in-Aid for Scientific Research) Background The conversion from initial non-shockable to shockable rhythms during cardiopulmonary resuscitation (CPR) by emergency medical service (EMS) providers may be associated with neurologically intact survival after out-of-hospital cardiac arrest (OHCA). However, the prognostic significance of rhythm conversion according to the type of initial nonshockable rhythm is unclear. Purpose To determine the association between shock after conversion to shockable rhythm with neurologically intact survival after OHCA and shock delivery time (time from EMS-initiated CPR to first shock delivery) in patients with two types of initial unshockable rhythm. Methods We analyzed the records of 90,334 adult patients with witnessed OHCA of cardiac origin who were treated by EMS providers and had an initial unshockable rhythm. Data were obtained from a prospectively recorded Japanese nationwide Utstein-style database for a 5-year period (2013–2017). The primary outcome was 1-month neurologically intact survival, defined as a cerebral performance categories score from 1 to 2. Patients were divided into initial pulseless electrical activity (PEA) (n = 37,977 [42.0%]) and initial asystole (n = 52,357 [58.0%]) groups. Results In the initial PEA group, the crude rate of 1-month neurologically intact survival was significantly higher in the subsequently shocked than in the non-shocked patients (4.2% [121/2,896]) vs. 2.4% [857/35,081], p &lt;0.0001). After adjustment for ten prehospital variables, the adjusted odds ratios (aORs) of subsequent shock for 1-month neurologically intact survival compared to no shock delivery were as follows: shock delivery time &lt;10 min, 2.21 (95% confidence interval [CI], 1.77–2.77, p&lt; 0.0001); 10–14 min, 1.43 (0.89–2.28, p = 0.14); and ≥15 min, 0.36 (0.16–0.81; p = 0.013). In the initial asystole group, the crude rate of 1-month neurologically intact survival was significantly higher in the subsequently shocked than in the non-shocked (1.7% [47/2,687] vs. 0.4% [203/49,670], p &lt;0.0001). A multivariate logistic regression model showed that subsequent shock with a shock delivery time &lt;10 min was associated with increased odds of neurologically intact survival compared to no shock delivery (aOR, 5.67; 95% CI, 3.92–8.18; p &lt;0.0001). However, there were no significant differences in neurological outcomes between subsequently shocked and non-shocked patients when the shock delivery time was 10–14 min (p = 0.21) or ≥15 min (p = 0.91). Conclusions In patients with witnessed OHCA of cardiac origin and initial nonshockable rhythm, subsequent shock after conversion to shockable rhythm during CPR was associated with increased odds of 1-month neurologically intact survival only when shock was delivered &lt;10 min from EMS-initiated CPR, regardless of the type of initial rhythm. Further, in patients with initial PEA, subsequent shock was associated with decreased odds of neurologically intact survival when shock was delivered ≥15 min from EMS-initiated CPR.

Ventricular Fibrillation Recurrences in Successfully Shocked Out-of-Hospital Cardiac Arrests

Background and Objectives: The prognostic impact of ventricular fibrillation (VF) recurrences after a successful shock in out-of-hospital cardiac arrest (OOHCA) is still poorly understood, and some evidence suggests a potential pro-arrhythmic effect of chest compressions in this setting. In the present analysis, we looked at the short-term and long-term prognosis of VF recurrences in OOHCA. And their potential association with chest compressions. Materials and Methods: The Progetto Vita, prospectively collecting data on all resuscitation efforts in the Piacenza province (Italy), was used for the present analysis. From the 461 OOHCAs found in a shockable rhythm, only those with optimal ECG tracings and good audio recordings (160) were assessed. Rhythms other than VF post-shock were analyzed five seconds after shock delivery and survival to hospital admission, hospital discharge, and long-term survival data over a 14-year follow-up were collected. Results: Population mean age was 64.4 ± 16.9 years, and 31.9% of all patients were female. Mean time to EMS arrival was 5.9 ± 4.5 min. Short- and long-term survival without neurological impairment were higher in patients without VF recurrence when compared to patients with VF recurrence, independently from the pre-induction rhythm (p < 0.001). After shock delivery, VF recurrence was higher when chest compressions were resumed early after discharge and more vigorously. Conclusions: VF recurrences after a shock could worsen short and long-term survival. The potential pro-arrhythmic effect of chest compressions should be factored in when considering the real risks and benefits of this procedure.