Sudden Cardiac Arrest Patients Research Articles

Long term prognosis after return of spontaneous circulation in sudden cardiac arrest patients

Long term prognosis after return of spontaneous circulation in sudden cardiac arrest patients

A Review on the Design of Non-Contact Vital Signs (NCVS) Biosensors for Long-Term Continuous Monitoring

It has been the dream of many scientists and engineers to realize a non-contact remote biosensing system that can perform continuous, accurate, and long-term monitoring of human vital signs as what we saw in some SciFi movies. Having a system that can measure and record key vital signs (such as heart rates and respiration rates) remotely and continuously without touching the patients, for example, can be an invaluable tool for physicians who need to make rapid life-and-death decisions. Such a system would also be an effective tool to help physicians and patients make better informed decisions when viewing a patient’s long-term monitored data. Therefore, there has been a large increase in research activities to develop a system that can monitor a patient’s vital signs and quickly transmit the information to healthcare professionals. Radio-Frequency (RF) Non-contact vital signs (NCVS) monitoring system are particularly attractive for long term vital signs monitoring because there are no wires, electrodes, wearable devices, nor contact-based sensors for the subjects to worry about. Approach: In this paper, we will provide a brief review on some latest development on NCVS sensors, and also compare them against a novel phased-array Doppler-based RF non-contact NCVS biosensor system we have built in our RF-SoC Lab. To determine the accuracy of our NCVS sensor, the heart rate measurements from our NCVS system are compared against an external contact-based piezoelectric finger sensor as a reference. Objective: In some of our previous works, the NCVS sensor performance was tested within a clutter-free anechoic chamber inside our Lab to mitigate the environmental clutters. To examine the performance of our NCVS sensor in a more practical setting, most tests here were performed within the typical Herman-Miller type office cubicle setting, inside a section of our Lab. Additionally, we will detail the measurement data to demonstrate the feasibility of long-term noncontact vital signs monitoring. Conclusion: The measured data strongly suggests that our latest phased array NCVS system should be able to perform long-term vital signs monitoring, especially for situations where the subject is sleeping and there is not expected to have hectic movements nearby. Recommendation: Our phased-array NCVS biosensor system appears to be quite robust and attractive. We will be performing several 24-hours tests to quantitatively analyze the effects of the background noise to long-term vital signs monitoring in office cubicle setting, and report our findings on these important topics in the near future. In the future, we also plan to continue to perform long-term NCVS monitoring on subjects during their sleep next for potential applications on sleep apnea and sudden cardiac arrest (SCA) patients.

Abstract 19422: Origin of Ventricular Fibrillation in Bileaflet Mitral Valve Prolapse Syndrome

Introduction: Although most patients with mitral valve prolapse (MVP) have a benign prognosis, there is a subgroup with bileaflet MVP syndrome (biMVPS) at increased risk of idiopathic ventricular fibrillation (VF). The phenotypic features of this syndrome include myxomatous bileaflet prolapse, complex ventricular ectopy (VE), T-wave inversion in inferolateral ECG leads, and female predominance. The mechanism of ventricular arrhythmia in these patients is unknown. Methods: We reviewed our center’s ablation experience of 14 consecutive patients with biMVPS patients between February 2007 and October 2013 (n=13 female, median [range] age at index ablation 33.8 [21.0 - 58.7] years, left ventricular ejection fraction [EF] 60 [45-67] %, all ≤ moderate mitral regurgitation [MR]). We compared findings from 6 with prior sudden cardiac arrest (SCA) and recurrent ICD shocks for drug refractory VF with 8 who had symptomatic drug-refractory complex VE but without prior SCA. Results: All patients with prior SCA had a predominant VE trigger for the VF. There was no difference between the two groups in EF, MR severity, VE burden, and number of different VE morphologies or foci ablated. Sites of successful VE ablation at index procedure were the LV papillary muscles (PM, n=6 anterior, 6 posterior), fascicular system (n=5 anterior, 4 posterior), mitral annulus (n=2), outflow tracts (3 RVOT, 1 LVOT), and coronary sinus (n=1). All patients had at least one LV papillary or fascicular VE focus. Purkinje origin VE was identified as the VF trigger in 6/6 SCA patients (3 from PM, 3 from LV fascicles) and only 4/8 (none from PM) non-SCA patients (p=0.04). Acute success was seen in 17/19 procedures with no complications. VF storm occurred within 24 hours of ablation in a single patient. At 310 (39 - 2099) days follow-up, 1 SCA patient received a single shock (p=0.031 compared to pre-ablation), and symptoms from VE were reduced in 12/14. Conclusions: BiMVPS is characterized by VE from the LV fascicles and papillary muscles that trigger VF. The VE is invariably multifocal and may also involve the outflow tracts and mitral annulus. Ablation of clinically dominant VE foci alleviates symptoms and reduces the number of VF-terminating ICD shocks.

Optimal placement of public-access AEDs in urban environments

Use of public-access Automated External Defibrillators (AEDs) is showing promising results in decreasing collapse-to-shock times among Sudden Cardiac Arrest (SCA) patients which is associated with improved patient outcomes. Bystander access to these medical devices ensure that the necessary care to victims of SCA is provided prior to arrival of emergency responders. Prior studies have suggested methods for deploying AEDs for public use by implementing mathematical optimization based on historic incidences of SCA. The purpose of this study is to improve upon these studies by developing a novel method for generating placement plans in urban environments. The novelty of this study is: (1) the use of route-based walking time instead of straight-line approximations; (2) introduction of temporal availability in deployed devices to account for location hours-of-operation; (3) use of a multi-objective optimization to balance decision-maker objectives; and (4) the implementation of an interactive decision-maker tool for observing effects on benefits and costs. The approach is deployed and evaluated for a case study in the city of Hoboken, New Jersey. This case study is simulated with a resulting average decrease of time-to-retrieve by 98.06s indicating an estimated 11.44–16.30% survival probability improvement using our optimization technique compared to a baseline optimization.

Mitral valve prolapse and sudden cardiac arrest in the community

Mitral valve prolapse (MVP) is relatively common in the general population with recently reported prevalence of 1% and familial clustering (Framingham Heart Study). However, its association with ventricular arrhythmias and sudden cardiac arrest (SCA) remains controversial. The purpose of this study was to characterize the frequency and clinical profile of patients with MVP who suffer SCA in the community. Patients with SCA cases were prospectively identified in the population-based Oregon Sudden Unexpected Death Study (population ~1 million). The presence of MVP was identified from echocardiograms recorded prior but unrelated to the SCA event. The detailed clinical profile of patients with SCA and MVP was compared with that of SCA patients without MVP to identify potential differences. A total of 729 SCA patients were evaluated over a 12-year period (mean age 69.5 ± 14.8 years; 64.6% men). MVP was observed in 17 (2.3%) prior to the SCA event (95% confidence interval 1.2%-3.4%). Mitral regurgitation was present in 14 SCA patients with MVP (82.3%) and was moderate or severe in 10 (58.8%). Compared with SCA patients without MVP, SCA patients with MVP were younger (mean age 60.9 ± 16.4 years vs 69.7 ± 14.7 years; P = .02), with fewer risk factors (diabetes 5.9% vs 46.4%; P = .001; hypertension 41.2% vs 78.9%; P = .001) or known coronary disease (29.4% vs 65.6%; P < .001). MVP was observed in a small proportion (2.3%) of SCA patients in the general population, suggesting a low risk overall. Since SCA patients with MVP were characterized by younger age and relatively low cardiovascular comorbidity, a focus on imaging for valve structure/insufficiency as well as genetics could aid future risk stratification approaches.

Understanding Brugada syndrome.

Brugada syndrome is an established cause of sudden cardiac arrest in patients without structural cardiac abnormalities. Recognition and diagnosis of this syndrome has been slowly increasing. Syncope, ventricular dysrhythmia, or sudden cardiac arrest may be the presenting symptom, although detection of the characteristic right precordial ST-segment elevation on ECG can be a potentially lifesaving intervention. This article reviews the clinical presentation, pathophysiology, genetics, and current management of Brugada syndrome.

Board #135 - Research Abstract Interim Results of Randomized Controlled Simulation Testing of Standard and Automated Device-Assisted Pre-hospital Cardiac Arrest Resuscitation Approaches (Submission #8205)

Hypothesis Automation of labor-intensive, repetitive and critical sudden cardiac arrest (SCA) resuscitation tasks will result in improved resuscitation quality. Automated device-assisted SCA protocols and equipment will de-emphasize the hierarchical BLS-ALS classification of SCA resuscitation activities without adversely impacting resuscitation quality. A comprehensive, high-resolution simulation assessment methodology with meaningful objective metrics can be used to realistically and progressively assess standard and experimental approaches to prehospital SCA resuscitation. LUCAS2 chest compressor, automated external defibrillation (AED) guidance, supraglottic airway (SGA or ILMA), portable mechanical ventilator, EZ-IO access device, limited selection of SCA medication. Methods EMS teams (each comprising one EMT-B and one ALS provider) were randomized to control group or experimental group. Each team engaged in 3 SCA simulations: 1) baseline scenario in standard roles; 2) repeat scenario in standard roles; and 3) repeat scenario in reversed roles, for example, BLS provider performing ALS tasks. Control teams operated with standard state protocols and equipment only (with 30-min sham intervention on high-performance CPR); experimental teams used resuscitation-automating devices and accompanying goal-directed algorithmic resuscitation protocol for scenarios 2 and 3 (with 30-min in-servicing). Audiovisual records, simulator logs and PC screencaptures collected data on chest compression, defibrillation, airway management, ventilation, vascular access, medications and transport. Team performance data were extracted and scored on each dimension relative to the best and worst performances for each scenario, with ACLS guidelines used as the gold standard when possible. Results Five control teams and five experimental teams of an anticipated 20-team sample have completed the study (10 EMT-Bs, 6 EMT-Cs, 4 EMT-Ps; mean age 30 years [range 21-52], mean 6 years at primary practice [2-21]; mean 20 SCA patient experience [0-200]). Baseline performance of chest compression and defibrillation was poor in both groups. Control teams performed similarly across scenarios 1 and 2 despite high-performance CPR didactic and skills stations. Experimental teams’ resuscitations improved in most areas, i.e., compression (mean depth: 41% of best performance scenario 1; 91% scenario 2), proportion of adequate compressions (11%; 61%), airway management (40%; 80%), ventilation (22%; 79%), vascular access (20%; 100%) and medication administration (20%; 100%). These improvements persisted in experimental groups when provider roles were reversed for the third scenario; control groups with standard protocols and reversed roles exhibited reduced resuscitation quality in all areas. Conclusion Automated assistance of critical, time- and resource-intensive SCA resuscitation tasks by electromechanical adjuncts improved the in-simulation performance of 2-provider EMS teams on nearly all resuscitation parameters studied. These improvements were maintained in experimental teams even with reversal of BLS and ALS provider roles. Although there are costs and risks to implementing resuscitation-automating protocols and equipment, the early suggestion of a strong trend towards improved clinical management hints at the potential real-world value of this approach. The simulation assessment methodology employed by the ongoing study has facilitated the analysis and innovative representation of prehospital clinical practice performance and will be applied to continuing and future studies. Disclosures Leo Kobayashi receives grant support from the University Emergency Medicine Foundation and Lifespan. Nicolas Asselin’s spouse receives salary support and owns stock in Biogen, Idec of Cambridge Massachusetts.

Cardiac anxiety after sudden cardiac arrest: Severity, predictors and clinical implications

BackgroundSurvival from cardiac arrest is a medical success but simultaneously produces psychological challenges related to perception of safety and threat. The current study evaluated symptoms of cardiac-specific anxiety in sudden cardiac arrest (SCA) survivors and examined predictors of cardiac anxiety secondary to cardiac arrest. MethodsA retrospective, cross-sectional study of 188 SCA survivors from the Sudden Cardiac Arrest Association patient registry completed an online questionnaire that included a measure of cardiac anxiety (CAQ) and sociodemographic, cardiac history, and psychosocial adjustment data. CAQ scores were compared to published means from implantable cardioverter defibrillator (ICD), inherited long QT syndrome (LQTS), and hypertrophic cardiomyopathy (HCM) samples and a hierarchical regression was performed. ResultsClinically relevant cardiac anxiety and cardioprotective behaviors were frequently endorsed and 18% of survivors reported persistent worry about their heart even when presented with normal test results. Compared to all other samples, SCA survivors reported significantly higher levels of heart-focused attention (d=0.3–1.1) and greater cardiac fear and avoidance behaviors than LQTS patients. SCA patients endorsed less severe fear and avoidance symptoms than the HCM sample. Hierarchical regression analyses revealed that younger age (p=0.02), heart murmur (p=0.02), history of ICD shock≥1 (p=0.01), and generalized anxiety (p=0.008) significantly predicted cardiac anxiety. The overall model explained 29.2% of the total variance. ConclusionsSCA survivors endorse high levels of cardiac-specific fear, avoidance and preoccupation with cardiac symptoms. Successful management of SCA patients requires attention to anxiety about cardiac functioning and security.

Temporal complexity of depolarization indicates myocardial sympathetic denervation and predicts sudden cardiac arrest in patients with ischemic cardiomyopathy and poor left ventricular ejection fraction

Temporal complexity of depolarization indicates myocardial sympathetic denervation and predicts sudden cardiac arrest in patients with ischemic cardiomyopathy and poor left ventricular ejection fraction Salah Al-Zaiti, CRNP, PhD, Amit Sethi, OTR/L, PhD, Mary Carey, RN, PhD, FAHA, John Canty,MD, FAHA, James Fallavollita, MD, FAHA University of Pittsburgh, Pittsburgh, PA, USA University of Rochester Medical Center, Rochester NY, USA VA WNY Health Care System at Buffalo, Buffalo, NY, USA The Center for Research in Cardiovascular Medicine, Buffalo, NY, USA The State University of New York at Buffalo, Buffalo, NY, USA

ECG imaging of altered electrical properties of myocardium in myocardial infarction

Temporal complexity of depolarization indicates myocardial sympathetic denervation and predicts sudden cardiac arrest in patients with ischemic cardiomyopathy and poor left ventricular ejection fraction Salah Al-Zaiti, CRNP, PhD, Amit Sethi, OTR/L, PhD, Mary Carey, RN, PhD, FAHA, John Canty,MD, FAHA, James Fallavollita, MD, FAHA University of Pittsburgh, Pittsburgh, PA, USA University of Rochester Medical Center, Rochester NY, USA VA WNY Health Care System at Buffalo, Buffalo, NY, USA The Center for Research in Cardiovascular Medicine, Buffalo, NY, USA The State University of New York at Buffalo, Buffalo, NY, USA

Application value of laryngeal mask airway and trachea cannula under different conditions of emergency medical service

First-aid stations were divided randomly into 4 groups. Advanced airway for sudden cardiac arrest patients with laryngeal mask airway (LMA) was established in groups A and C while trachea cannula was inserted on spot of emergency medical service (EMS) or in ambulance in groups B and D. According to the results, the success rate of insertion and cardiopulmonary resuscitation (CPR) of groups A and C were higher than the other two groups (P<0.05). However, the required time was shorter (P<0.05). Due to a difficult catheterization environment, LMA is more effective and convenient than trachea cannula in EMS. Key words: emergency medical service; laryngeal mask airway

Evaluation of genes encoding for the transient outward current (Ito) identifies the KCND2 gene as a cause of J-wave syndrome associated with sudden cardiac death.

J-wave ECG patterns are associated with an increased risk of sudden arrhythmic death, and experimental evidence supports a transient outward current (I(to))-mediated mechanism of J-wave formation. This study aimed to determine the frequency of genetic mutations in genes encoding the I(to) in patients with J waves on ECG. Comprehensive mutational analysis was performed on I(to)-encoding KCNA4, KCND2, and KCND3 genes, as well as the previously described J-wave-associated KCNJ8 gene, in 51 unrelated patients with ECG evidence defining a J-wave syndrome. Only patients with a resuscitated cardiac arrest or type 1 Brugada ECG pattern were included for analysis. A rare genetic mutation of the KCND2 gene, p.D612N, was identified in a single patient. Co-expression of mutant and wild-type KCND2 with KChIP2 in HEK293 cells demonstrated a gain-of-function phenotype, including an increase in peak I(to) density of 48% (P<0.05) in the heterozygous state. Using computer modeling, this increase in Ito resulted in loss of the epicardial action potential dome, predicting an increased ventricular transmural Ito gradient. The previously described KCNJ8-S422L mutation was not identified in this cohort of patients with ECG evidence of J-wave syndrome. These findings are the first to implicate the KCND2 gene as a novel cause of J-wave syndrome associated with sudden cardiac arrest. However, genetic defects in I(to)-encoding genes seem to be an uncommon cause of sudden cardiac arrest in patients with apparent J-wave syndromes.

Analyzing cardiac rhythm in the presence of chest compression artifact for automated shock advisory

Defibrillation is often required to terminate a ventricular fibrillation or fast ventricular tachycardia rhythm and resume a perfusing rhythm in sudden cardiac arrest patients. Automated external defibrillators rely on automatic ECG analysis algorithms to detect the presence of shockable rhythms before advising the rescuer to deliver a shock. For a reliable rhythm analysis, chest compression must be interrupted to prevent corruption of the ECG waveform due to the artifact induced by the mechanical activity of compressions. However, these hands-off intervals adversely affect the success of treatment. To minimize the hands-off intervals and increase the chance of successful resuscitation, we developed a method which asks for interrupting the compressions only if the underlying ECG rhythm cannot be accurately determined during chest compressions. Using this method only a small percentage of cases need compressions interruption, hence a significant reduction in hands-off time is achieved. Our algorithm comprises a novel filtering technique for the ECG and thoracic impedance waveforms, and an innovative method to combine analysis from both filtered and unfiltered data. Requiring compression interruption for only 14% of cases, our algorithm achieved a sensitivity of 92% and specificity of 99%.

Erythrocyte very long-chain saturated fatty Acids associated with lower risk of incident sudden cardiac arrest

Prior studies suggest that circulating n-3 and trans-fatty acids influence the risk of sudden cardiac arrest (SCA). Yet, while other fatty acids also differ in their membrane properties and biological activities which may influence SCA, little is known about the associations of other circulating fatty acids with SCA. The aim of this study was to investigate the associations of 17 erythrocyte membrane fatty acids with SCA risk. We used data from a population-based case-control study of SCA in the greater Seattle, Washington, area. Cases, aged 25–74 years, were out-of-hospital SCA patients, attended by paramedics (n=265). Controls, matched to cases by age, sex and calendar year, were randomly identified from the community (n=415). All participants were free of prior clinically-diagnosed heart disease. Blood was obtained at the time of cardiac arrest by attending paramedics (cases) or at the time of an interview (controls). Higher levels of erythrocyte very long-chain saturated fatty acids (VLSFA) were associated with lower risk of SCA. After adjustment for risk factors and levels of n-3 and trans-fatty acids, higher levels of 20:0 corresponding to 1 SD were associated with 30% lower SCA risk (13–43%, p=0.001). Higher levels of 22:0 and 24:0 were associated with similar lower SCA risk (ORs for 1 SD-difference: 0.71 [95% CI: 0.57–0.88, p=0.002] for 22:0; and 0.79 [95% CI: 0.63–0.98, p=0.04] for 24:0). These novel findings support the need for investigation of biologic effects of circulating VLSFA and their determinants.

Sudden cardiac arrest recorded during Holter monitoring: prevalence, antecedent electrical events, and outcomes.

Causative arrhythmias of sudden cardiac arrest (SCA) are changing in this age of improved coronary care. The purpose of this study was to examine the frequency of terminal arrhythmias and the electrical events prior to SCA. We analyzed 24-hour Holter recordings of 132 patients enrolled from 41 institutions who either died (n = 88) or had an aborted death (n = 44). The Holter recordings were obtained for diagnosing and evaluating diseases and arrhythmias in those without any episodes suggestive of SCA. In 97 patients (73%), SCA was associated with ventricular tachyarrhythmias and in 35 (27%) with bradyarrhythmias. The bradyarrhythmia-related SCA patients were older than those with a tachyarrhythmia-related SCA (70 ± 13 years vs. 58 ± 19 years, P < .001). The most common arrhythmia for a tachyarrhythmia-related SCA was ventricular tachycardia degenerating to ventricular fibrillation (45%). The bradyarrhythmia-related SCA was caused by asystole (74%) or AV block (26%). Spontaneous conversion was observed in 37 patients (38%) with ventricular tachyarrhythmias. Of those, 62% of the patients experienced symptoms including syncope, chest pain, or convulsion. Multivariate logistic analysis revealed that independent predictors of mortality for tachyarrhythmia-related SCAs were advanced age (odds ratio 1.04, 95% confidence interval 1.02-1.08) and ST elevation within the hour before SCA (odds ratio 3.54, 95% confidence interval 1.07-13.5). In contrast, the presence of preceding torsades de pointes was associated with spontaneous conversion (odds ratio 0.20, 95% confidence interval 0.05-0.66). The most frequent cause of SCA remains ventricular tachyarrhythmias. Advanced age and ST elevation before SCA are risk factors for mortality in tachyarrhythmia-related SCAs.

Analysis of the spatial and transmural dispersion of repolarization and late potentials derived using signal-averaged vector-projected 187-channel high-resolution electrocardiogram in patients with early repolarization pattern

BackgroundElectrophysiological characteristics of early repolarization syndrome (ERS), i.e., the spatial and transmural dispersion of ventricular repolarization and ventricular late potentials can be evaluated using a signal-averaged vector-projected 187-channel high-resolution electrocardiogram (187-ch SAVP-ECG). We investigated these characteristics as markers of ventricular fibrillation and sudden cardiac arrest in patients presenting with an ER pattern. MethodsThe 187-ch SAVP-ECGs were recorded for 8 patients with idiopathic ventricular fibrillation associated with ERS (ERS patients), and 5 patients with an ER pattern without arrhythmic events (ER pattern patients). ResultsThe ER pattern was located in the inferior leads (n=7), lateral leads (n=1), or both inferior and lateral leads (n=5). The corrected RT(RTc) (peak point of the R wave − positive maximum peak of the first derivative of the T wave interval corrected using the Bazett formula) interval and T(peak-end)-c interval from the 187 channels were calculated. Late potentials were positive in 7 of 8 ERS patients and in 3 of 5ER pattern patients (P=0.25). The average RTc was shorter in patients with ERS (192.6±29.8ms vs. 234.0±25.5ms, P=0.04). However, average T(peak-end)-c interval did not differ between the 2 groups. ConclusionLate ventricular potentials were common in ERS and ER pattern patients. Lethal arrhythmia in ERS patients appeared to be related to the relatively short average repolarization time rather than the spatial and transmural dispersion of repolarization.

Additional responsibility for physicians caring for cardiac patients: Insight from a case series

Resuscitation measures performed at the scene of the event have the ultimate impact on the outcome of a cardiac arrest. We analysed six case histories of those sudden cardiac arrest patients who were revived in the field and were subsequently admitted to the intensive care unit during a six-month period. All were known cardiac patients and were under the care of healthcare providers. Four of those were discharged home from the hospital and did not suffer any residual damage where as one died of multi-organ failure and the other was declared brain dead. The outcome was good in patients who received early intervention in the form of basic life support. The family members of non-survivors witnessed the cardiac arrest at home but were not familiar with the concept or procedures of basic life support. We propose that physicians who care for cardiac patients should undertake the task of increasing family member awareness and knowledge in the techniques of basic life support.

The clinical characteristics of sudden cardiac arrest in asymptomatic patients with congenital heart disease

Sudden cardiac arrest (SCA) is a major cause of death in patients with congenital heart disease (CHD). Systemic ventricular dysfunction is a reported risk factor for SCA. We retrospectively analyzed the medical records of 46 patients (age >6 years) who experienced SCA. The following underlying cardiac defects were observed: biventricular repair with affected subpulmonary right ventricle (n = 18, 39 %), biventricular repair with systemic right ventricle and Eisenmenger syndrome (n = 6 each, 13 %), Fontan circulation and unrepaired CHD (n = 5 each, 11 %), and others (n = 6, 13 %). Twenty-one patients (46 %) had no history of arrhythmias, and 21 of 43 (49 %) showed systemic ventricular ejection fraction >55 %. According to the New York Heart Association classification, 18 patients (39 %) were class I and 28 (61 %) were class II/III. SCA occurred at a younger age in class I (16 ± 5 years) than in the other classes (23 ± 10 years; P = 0.004). QRS duration was similar between the groups (136 ± 38 vs. 141 ± 50 ms; P not significant). Seven patients in class I (15 % of all SCAs) had no history of arrhythmias or features of hemodynamic abnormalities. The proportion of patients with biventricular repair and affected subpulmonary right ventricle was higher than that of patients with other defects, and the majority of SCA patients had more complicated defects than a simple repaired ventricular septal defect or an atrial septal defect. No symptoms of heart failure, history of arrhythmias, or features of hemodynamic abnormalities were observed in 15 % of the patients who experienced SCA. Prolonged QRS duration might be a predictor of SCA even in asymptomatic CHD patients. Prevention of SCA in CHD patients may require more detailed evaluation than is typically considered necessary.

Abstract 351: The Family Study: Assessment of the Risk for Sudden Cardiac Arrest in Family Members of Cardiac Arrest Patients

Background: Sudden cardiac arrest (SCA) is devastating for the patient’s family, friends, and community. There is limited information on its identifiable familial predisposition. Objectives: To evaluate the familial risk pattern for SCA in family members of cases compared to age-and-sex matched control groups. Incidence of prior symptoms and SCA triggers were also compared. Methods: We used a prospectively collected, population-based registry of all out-of-hospital cardiac arrests (OHCAs) in the Greater Toronto Area, to identify cases from 2010-2012. Cases were defined as SCA patients aged 18-65 who arrested from a cardiac cause and were treated by Emergency Medical Services. Two relatives per patient were interviewed regarding symptoms prior to the arrest, cardiac history and family history of SCA. Control patients with known coronary heart disease (CHD) and healthy participants were recruited from PCI procedures and the Family Practice Units at St. Michael’s Hospital. Results: Complete family and medical history was obtained for 66 SCA cases, 56 heart disease patients and 27 healthy controls. Underlying diseases were CHD in 77%, non-CHD structural heart disease in 9%, primary arrhythmic in 3% and presumed cardiac of unknown etiology in 11%. A higher proportion of SCA individuals had a family history of SCA in 1st degree relatives (19/66; 28.8%) than 1st degree relatives of healthy controls (2/27; 7%; p=0.006) and 1st degree relatives of patients with heart disease (14/56; 25%) (Table 1). Among families with SCA, 3/66 (4.5%) had a history of &gt;1 relative with SCA, vs. none in either control group. Most SCA patients experienced one or more warning symptoms in the hour preceding an arrest (40/66; 61%); 24/66 (36%) experienced a cardiac arrest during or following exercise. Conclusion: Family members of SCA patients have a higher SCA prevalence than family members of healthy controls. A high proportion of SCA patients experienced symptoms in the hour preceding their arrest.

Abstract 271: Predicting Defibrillation Success Without Interrupting Chest Compression in Cardiac Arrest Patients

Background: In performing CPR on sudden cardiac arrest patients, a balance between chest compressions (CC) and defibrillation is needed. Optimizing the timing of defibrillation shocks may improve outcomes compared to time-based protocols. There exist numerous predictive features computed from the ECG signal before shock delivery to distinguish between rhythms which convert to spontaneous circulation and those which do not. Unfortunately, since CC induce significant artifact on the ECG signal, all these features assume a pause in CC before delivering the shock, so that there is no CC artifact on the ECG signal to be analyzed. However, in the 2010 guidelines, the AHA challenges manufacturers to “seek innovative methods to decrease the amount of time chest compressions are interrupted for AED operation.” It would be beneficial if the predictive features could be calculated while CC are performed and CC artifact is present. Objective: Examine the effects of CC artifact on shock success predictive features and how such effects can be minimized. Methods: A total of 111 short waveform segments from cardiac arrest patients with VF rhythm and transition from CC to hands-off were used. Thirteen temporal and spectral predictive features were calculated on a 4-sec “noisy” interval containing CC artifact preceding the transition at the end of CC, and on the adjacent 4-sec “clean” interval with no CC artifact following the transition. We presumed the underlying VF remained constant during both intervals. Predictive features were then calculated on a “filtered” version of the noisy segments with CC artifact removed using a newly developed method. Results: The Wilcoxon signed-rank paired test showed CC artifact had a significant impact on all predictive features. However, after removal of CC artifact using our filter, the test showed all but one feature gave similar values to those from the “clean” segments. Conclusion: The results demonstrate that CC artifact has a significant impact on shock success predictive features, but that the effect can be minimized using our CC artifact filtering method. Large prospective studies are needed to show if a combination of our filtering method and predictive features can help minimize CC interruptions and improve resuscitation outcomes.