Incidence Of Sudden Cardiac Arrest Research Articles

Abstract 227: Sudden Cardiac Arrest During Exercise Occurs Infrequently and With Few Warning Symptoms

Introduction: The incidence and details of sudden cardiac arrest (SCA) during exercise in the general population are not well described. We describe a cohort ages 2-85 who experienced an SCA within ≤ 1 hour of moderate to vigorous activity in 4 metropolitan areas of British Columbia, Canada. Methods: We reviewed prehospital records of consecutive out-of-hospital cardiac arrests (OHCAs) in the provincial BC OHCA Registry from June 17 2017 to August 16 2018. We included non-traumatic OHCAs treated by EMS occurring within ≤ 1 hour of exercise. We defined SCA as an OHCA of no obvious cause, witnessed/unwitnessed, survived/died. We assigned an estimated metabolic equivalent (MET) score to each type of physical activity. We defined moderate exercise as a MET score of 3-5.9 and vigorous as ≥6. Results: A total of 2674 OHCAs occurred during the study period of which 56 SCAs (2.1%) occurred within ≤1 hour of participation in 23 types of exercise (Figure 1). The incidence of SCA during exercise was 1.45 (95% CI 1.10-1.88) per 100,000 population. The median age was 56.5 [IQR 45-69] and 87.5% (49/56) were male. Most exercise related SCAs occurred in public (49/56 87.5%), 83.3% (45/54) were bystander witnessed and 85% (46/54) received bystander CPR. Over 70% (40/56) had a shockable rhythm. The survival rate was 55.4% (31/56). Half of the SCAs collapsed during exercise (49.1%; 26/53) while the other half collapsed within ≤1 hour after exercising (51%; 27/53). Symptom data were available in 46% of patients (23/50) with most experiencing chest pain, dizziness, feeling unwell or seizure just prior to collapse. Conclusions: SCAs during exercise are rare and frequently occur in a public location. Survival is high and may be related to witnessed and public location status. Equal numbers of SCAs collapsed during or ≤ 1 hour of exercising and symptoms were present in almost half. Future research is needed to determine what factors could predict those at highest risk for SCA in order to prevent future events.

P4427Cardiovascular outcomes among runners of a marathon race - a 17 years' experience

Abstract Introduction Over the past 17 years (2002–2018), 898,831 people participated in the Hong Kong Standard Chartered Marathon (HKSCM). Purpose We aim to study the incidence of marathon-related sudden cardiac arrest (SCA) and non-fatal myocardial injury (NFMI). Methods All the HKSCM related admissions between 2002 and 2017 were retrieved from the accident and emergency department admission records. We reviewed the data of HKSCM runners admitted for SCA and NFMI. Results Fourteen and thirty-nine runners were admitted for SCA (Mean age 38±13 years-old, 12 men) and NFMI (Mean age 42±12 years-old; 34 men) respectively. Among the SCA runners, the arrest rhythms could not be retrieved in 3 cases. In the remaining 11 SCA runners, the arrest rhythms were ventricular fibrillation (VF) (N=6), pulseless-electrical activity (PEA) (N=3), and asystole (N=2). Nine of the 14 SCA runners were successfully resuscitated. Only 2 out of the 14 SCA runners had significant atherosclerotic coronary artery disease (CAD) requiring coronary angioplasty. Among the SCA runners, the etiologies of cardiac arrest were myocardial infarction (MI) (N=2), ischemic cardiomyopathy with VF (N=1), idiopathic VF (N=3), malignant coronary anomaly (N=1), and idiopathic (N=5). Percutaneous coronary intervention (PCI) was performed in 2 SCA runner with MI. Implantable cardioverter-defibrillators were implanted in 1 resuscitated runner with VF. Postmortem examination of the 3 deceased runners showed significant CAD in two and was unrevealing in one. Among the 39 NFMI runners, coronary angiograms (CAG) or CT coronary angiogram were performed in 14 cases (36%), which showed minor CAD or unremarkable findings in 7 runners, and significant CAD in 7 runners. PCI and coronary artery bypass were performed in 5 and 2 NFMI runners respectively. Only 8 out of 39 NFMI runners reported chest pain. Significant ischemic ECG changes were detected in 9 out of 39 NFMI runners. Invasive CAGs were not performed in the remaining NFMI runners due to low pre-test likelihood of CAD and normal non-invasive test results. Conclusions The incidence of SCA and mortality among HKSCM runners was 1.56 per 100,000 and 0.56 per 100,000 respectively. The incidence of NFMI was 4.3 per 100,000. Coronary artery disease, coronary anomaly and idiopathic VF were the commonest etiologies of SCA.

Association between the Incidence of Sudden Cardiac Arrest and the Location of Culprit Lesions in STEMI Patients – Design of a Prospective Clinical Study

Abstract Out-of-hospital cardiac arrest (OHCA) has a poor prognosis and is the most severe complication of any cardiac event. It is known from previous studies that the location of the culprit lesion in ST-segment elevation myocardial infarction (STEMI) patients with cardiac arrest may affect the post resuscitation survival rate. However, due to the low number of cases, the association between the localization of the culprit lesion within the coronary tree and the occurrence of cardiac arrest is not widely discussed, because resuscitated cardiac arrest patients are excluded from the vast majority of clinical trials. This is a prospective observational study that aims to develop a prediction model for OHCA in patients who present with STEMI, based on differences related to culprit lesion location. The primary objective of the study is to evaluate the differences related to the location of the culprit lesion in patients with STEMI who present OHCA versus patients without cardiac arrest.

Medical facilities in the neighborhood and incidence of sudden cardiac arrest

BackgroundMedical establishments in the neighborhood, such as pharmacies and primary care clinics, may play a role in improving access to preventive care and treatment and could explain previously reported neighborhood variations in sudden cardiac arrest (SCA) incidence and survival. MethodsThe Cardiac Arrest Blood Study Repository is a population-based repository of data from adult cardiac arrest patients and population-based controls residing in King County, Washington. We examined the association between the availability of medical facilities near home with SCA risk, using adult (age 18–80) Seattle residents experiencing cardiac arrest (n = 446) and matched controls (n = 208) without a history of heart disease. We also analyzed the association of major medical centers near the event location with emergency medical service (EMS) response time and survival among adult cases (age 18+) presenting with ventricular fibrillation from throughout King County (n = 1537). The number of medical facilities per census tract was determined by geocoding business locations from the National Establishment Time-Series longitudinal database 1990–2010. ResultsMore pharmacies in the home census tract was unexpectedly associated with higher odds of SCA (OR:1.28, 95% CI: 1.03, 1.59), and similar associations were observed for other medical facility types. The presence of a major medical center in the event census tract was associated with a faster EMS response time (−53 s, 95% CI: −84, −22), but not with short-term survival. ConclusionsWe did not observe a protective association between medical facilities in the home census tract and SCA risk, orbetween major medical centers in the event census tract and survival.

Sudden Cardiac Death: Interface Between Pathophysiology and Epidemiology.

The population incidence of sudden cardiac arrest (SCA) and sudden cardiac death have not changed appreciably during the decades of improvement in general outcomes from cardiovascular diseases, but the age, clinical circumstances, and pathophysiologic mechanisms have. The epidemiology and pathophysiology of SCA are linked, in that mechanisms of SCA can be modeled based on substrate and expression characteristics. The goal for the future is to expand pathophysiologic and epidemiologic interactions to achieve strong individual risk prediction, to complement the limits of application of population risk data to individuals.

Sudden Cardiac Arrest during Participation in Competitive Sports

BackgroundThe incidence of sudden cardiac arrest during participation in sports activities remains unknown. Preparticipation screening programs aimed at preventing sudden cardiac arrest during sports activities are thought to be able to identify at-risk athletes; however, the efficacy of these programs remains controversial. We sought to identify all sudden cardiac arrests that occurred during participation in sports activities within a specific region of Canada and to determine their causes.MethodsIn this retrospective study, we used the Rescu Epistry cardiac arrest database (which contains records of every cardiac arrest attended by paramedics in the network region) to identify all out-of-hospital cardiac arrests that occurred from 2009 through 2014 in persons 12 to 45 years of age during participation in a sport. Cases were adjudicated as sudden cardiac arrest (i.e., having a cardiac cause) or as an event resulting from a noncardiac cause, on the basis of records from multiple sources, including ambulance call reports, autopsy reports, in-hospital data, and records of direct interviews with patients or family members.ResultsOver the course of 18.5 million person-years of observation, 74 sudden cardiac arrests occurred during participation in a sport; of these, 16 occurred during competitive sports and 58 occurred during noncompetitive sports. The incidence of sudden cardiac arrest during competitive sports was 0.76 cases per 100,000 athlete-years, with 43.8% of the athletes surviving until they were discharged from the hospital. Among the competitive athletes, two deaths were attributed to hypertrophic cardiomyopathy and none to arrhythmogenic right ventricular cardiomyopathy. Three cases of sudden cardiac arrest that occurred during participation in competitive sports were determined to have been potentially identifiable if the athletes had undergone preparticipation screening.ConclusionsIn our study involving persons who had out-of-hospital cardiac arrest, the incidence of sudden cardiac arrest during participation in competitive sports was 0.76 cases per 100,000 athlete-years. The occurrence of sudden cardiac arrest due to structural heart disease was uncommon during participation in competitive sports. (Funded by the National Heart, Lung, and Blood Institute and others.)

Comparative study of the incidence of early complications among the patients with six different kinds of acute organophosphorus pesticide poisoning.

Objective To explore the incidence of early complications within 72 hours among patients with six kinds of acute organophosphorus pesticide poisoning, thus to provide reference for the clinical treatment. Methods The retrospective study analyzed the clinical data of 335 cases with acute oral organophosphorus pesticide poisoning treated in Emergency Department of 307 Hospital of PLA from July 2008 to December 2015. Patients were divided into six groups according to the results of serum toxicology tests: acute phorate group (group A), acute dichlorvos group (group B), acute omethoate group(group C), acute dimethoate group (group D), acute phoxim group(group E) and acute parathion group(group F). The incidence of complications among the six groups were compared. The main analysis method was ranks test. Results There were no significant differences among the six groups in the incidence of cerebral edema, liver injury, kidney injury, myocardial injury, gastrointestinal hemorrhage and acute pancreatitis(P>0.05), while the mortality and the incidence of sudden cardiac arrest(SCA), respiratory failure, circulatory failure, multiple organ dysfunction syndrome (MODS), coagulation disorders and capillary leak syndrome(CLS) were significantly different among the six groups (P<0.05). The incidence of SCA wihin 24 hours in acutedichlorvos group reached up to 17.8%, and in other groups was as follows: acute parathion group (11.1%), acute dimethoate group (8.9%), acute phorate group (7.8%) and acute omethoategroup (1.5%). However, no one developed SCA in acute phoxim group. The total incidence of circulatory failure in all patients was 10.1%; dichlorvos group 31.1% and dimethoate group(22.2%) had higher rates than other groups. The incidence of respiratory failure in all groups reached over 20%, while the total incidence was 36.7%, whereby, acute phorate group with a high of 46.7%, acute dichlorvos group with 44.4%, acute parathion group with 44.4% and acute dimethoate group with 42.2%, respectively. The total incidence of coagulation disorders was 9.6%, while the incidences of the acute dichlorvos group (24.4%), acute phorate group (11.6%) and acute parathion group (11.1%) were higher than 10%. CLS confined to occur in acute dichlorvos group(11.1%) and acute phorate group(2.5%). However, MODS occurred mainly in acute dichlorvos group(28.9%) and acute parathion group(22.2%). Conclusions The incidences of early complications among the six groups are different, while acute oral dichlorvos poisoning patients tend to occur SCA. Within 72 h of poisoning, acute phorate poisoning group is more prone to respiratory failure, and acute dichlorvos poisoning group is more likely to develop coagulopathy disorders, circulation failure, CLS and MODS.Those patients in acute omethoate and acute phoxim poisoning groups have less risk to develop life-threatening complications except respiratory failure. Key words: Organophosphorus pesticide; Acute poisoning; Early complications; Comparative study

Clinical Presentation of Pediatric Patients at Risk for Sudden Cardiac Arrest

To identify the clinical presentation of children and adolescents affected by 1 of 4 cardiac conditions predisposing to sudden cardiac arrest: hypertrophic cardiomyopathy, long QT syndrome (LQTS), catecholaminergic polymorphic ventricular tachycardia (CPVT), and anomalous origin of the left coronary artery from the right sinus of Valsalva (ALCA-R). This was a retrospective review of newly diagnosed pediatric patients with hypertrophic cardiomyopathy, LQTS, CPVT, and ALCA-R referred for cardiac evaluation at 6 US centers from 2008 to 2014. A total of 450 patients (257 male/193 female; median age 10.1 years [3.6-13.8 years, 25th-75th percentiles]) were enrolled. Patient age was ≤13 years for 70.4% of the cohort (n = 317). Sudden cardiac arrest was the initial presentation in 7%; others were referred on the basis of abnormal or suspicious family history, personal symptoms, or physical findings. Patients with LQTS and hypertrophic cardiomyopathy were referred most commonly because of family history concerns. ALCA-R was most likely to have abnormal signs or symptoms (eg, exercise chest pain, syncope, or sudden cardiac arrest). Patients with CPVT had a high incidence of syncope and the greatest incidence of sudden cardiac arrest (45%); 77% exhibited exercise syncope or sudden cardiac arrest. This study demonstrated that suspicious or known family history plays a role in identification of many patients ultimately affected by 1 of the 3 genetic disorders (hypertrophic cardiomyopathy, LQTS, CPVT). Important patient and family history and physical examination findings may allow medical providers to identify many pediatric patients affected by 4 cardiac disorders predisposing to sudden cardiac arrest.

AUTOMATED CARDIAC ARREST DETECTION AND ALERTING SYSTEM USING A SMARTPHONE AND A STANDARD BLUETOOTH CHEST STRAP HEART RATE MONITOR DURING EXERCISE: THE “PARACHUTE” APP

Aerobic exercise is a healthy behaviour and prolongs life, but during vigorous exercise the incidence of sudden cardiac arrest, although small in absolute, is increased several times compared with resting. Runners and cyclers (>100 millions in US) often exercise where there is low probability that a

Abstract 11106: The Incidence of Sudden Cardiac Arrest Continues to Rise, but Outcome is at a Standstill in South Korea: Analyzed From National Health Insurance Database Cohort From 2003 to 2013

Introduction: Sudden cardiac arrest (SCA) is a major clinical and public health problem. South Korea is aging faster than any other country, and the disease spectrum has changed profoundly in the last few decades. The purpose of this study was to investigate the change of the incidence and outcome of SCA over the past ten years. Methods: With the use of the National Health Insurance Database Cohort (NHID-Cohort) consisting of one million patients from 2003 through 2013, we identified the patient with sudden cardiac arrest using Korean Standard Classification of Diseases, 6th Revision, code I46. Results: In all, 5,307 (0.52%) patients with SCA were identified between 2003 and 2013. SCA occurred more frequent in men (59.3%) than women (40.7%) (p&lt;0.001). The annual incidence of SCA increased by 116.3% from 28.9 in 2003 to 62.5 in 2013 (per 100,000 person-year, p&lt;0.001). The increase of SCA was particularly predominant in patients with ≥60 years of age (from 153.8 to 259.1 per 100,000 person-year, p&lt;0.001) and those with low economic status (from 27.5 to 85.2 per 100,000 person-year, p&lt;0.001). Health care cost per 100,000 person-year also increased from $65,866 in 2003 to $241,534 in 2013 (p&lt;0.001). However, there was no significant improvement in one-month survival rate during the same period (11.9% in 2003, 13.4% in 2013, p=0.526). Conclusions: The incidence of SCA in South Korea continues to rise over the past ten years, especially in elderly people. Despite the tremendous advances in the field of cardiovascular medicine, outcome of SCA is at a standstill.

Potassium kinetics during hemodialysis.

Hyperkalemia in hemodialysis patients is associated with high mortality, but prescription of low dialysate potassium concentrations to decrease serum potassium levels is associated with a high incidence of sudden cardiac arrest or sudden death. Improved clinical outcomes for these patients may be possible if rapid and substantial intradialysis decreases in serum potassium concentration can be avoided while maintaining adequate potassium removal. Data from kinetic modeling sessions during the HEMO Study of the dependence of serum potassium concentration on time during hemodialysis treatments and 30 minutes postdialysis were evaluated using a pseudo one-compartment model. Kinetic estimates of potassium mobilization clearance (K(M)) and predialysis central distribution volume (V(pre)) were determined in 551 hemodialysis patients. The studied patients were 58.8 ± 14.4 years of age with predialysis body weight of 72.1 ± 15.1 kg; 306 (55.4%) of the patients were female and 337 (61.2%) were black. K(M) and V(pre) for all patients were non-normally distributed with values of 158 (111, 235) (median [interquartile range]) mL/min and 15.6 (11.4, 22.8) L, respectively. K(M) was independent of dialysate potassium concentration (P > 0.2), but V(pre) was lower at higher dialysate potassium concentration (R = -0.188, P < 0.001). For patients with dialysate potassium concentration between 1.6 and 2.5 mEq/L (N = 437), multiple linear regression of K(M) and V(pre) demonstrated positive association with predialysis body weight and negative association with predialysis serum potassium concentration. Potassium kinetics during hemodialysis can be described using a pseudo one-compartment model.

Incidence of syncope and cardiac arrest in patients with severe aortic stenosis

Syncope and sudden cardiac arrest are known complications of aortic stenosis (AS). The aim of the study was to investigate the incidence of these complications in patients with severe symptomatic AS and to analyze whether basic clinical data and electrocardiographic (ECG) and echocardiographic parameters can be the markers of these complications. The incidence of syncope and sudden cardiac arrest and its correlations with clinical and diagnostic data (ECG, echocardiography, Holter monitoring) were analyzed in 514 patients (mean age, 60 ±11 y) with severe symptomatic AS before valve replacement. Syncope was reported in 167 patients (32%), and aborted cardiac arrest in 14 (2.7%; ventricular fibrillation, 13 patients; third-degree atrioventricular block, 1 patient). None of the analyzed parameters was related to syncope. Patients with a history of sudden cardiac arrest had higher New York Heart Association class (P = 0.01), more frequent history of syncope (P = 0.017), higher left ventricular mass index (P = 0.02), lower ejection fraction (P = 0.004), longer QRS duration (P = 0.048), corrected QT (P = 0.002), QT dispersion (P = 0.007), and a higher number of ventricular arrhythmias in 24-hour Holter monitoring (P = 0.002). A multivariate analysis showed correlations between syncope, ejection fraction of less than 45%, and QTd exceeding 60 ms and aborted cardiac arrest. At least 2 of these parameters were observed in 8 of 14 patients (P <0.001): sensitivity, 57%; specificity, 86%; positive predictive value, 10%; and negative predictive value, 98%. The incidence of sudden cardiac arrest in severe symptomatic AS is low. It is higher in patients with a history of syncope, prolongation of QTd, and reduced ejection fraction. None of the clinical and diagnostic parameters were associated with a history of syncope in patients with AS.

Incidence of sudden cardiac arrest in high school student athletes on school campus.

An accurate estimate of the incidence of sudden cardiac arrest (SCA) in high school student athletes is needed to guide prevention strategies. To prospectively investigate SCA rates in high school student athletes vs student nonathletes. A prospective observational study of 2149 US high schools participating in the National Registry for AED Use in Sports was conducted from August 2009 to July 2011. Schools were contacted quarterly to collect and review SCA cases occurring on school campus. Ninety-five percent (2045) of the schools confirmed participation for the entire 2-year period. The average numbers of total students and student athletes per school were 963 and 367, respectively, providing more than 4.1 million total student-years and more than 1.5 million student athlete-years of surveillance. Twenty-six cases of SCA occurred in students, including 18 cases in student athletes-all during exercise. The incidence of SCA in all students was 0.63 per 100,000; in student athletes, 1.14 per 100,000; and in student nonathletes, 0.31 per 100,000. The relative risk of SCA in student athletes vs nonathletes was 3.65 (95% confidence interval 1.6-8.4; P < .01). Sixteen of 18 (89%) student athletes with SCA were boys, resulting in an incidence of 1.73 per 100,000 in boys and 0.31 per 100,000 in girls and a relative risk in male compared with female student athletes of 5.65 (95% confidence interval 1.3-24.6; P < .01). The incidence of SCA in high school student athletes is higher than previous estimates and may justify more advanced cardiac screening and improved emergency planning in schools.

Most Important Outcomes Research Papers on Cardiac Arrest and Cardiopulmonary Resuscitation

Cardiac arrest is a common and treatable cause of death and disability. Each year ≈424 000 people experience emergency medical services (EMS)-assessed out-of-hospital cardiac arrest (OHCA) in the United States.1 The actual burden of OHCA is likely significantly higher because a substantial number go unassessed. In a prospective analysis of deaths in a US county, 5.6% of annual mortality was attributable to cardiac arrest.2 Many patients who suffer OHCA do not receive prompt cardiopulmonary resuscitation (CPR). Among those who receive CPR, a large number do not survive because of an inability to restore spontaneous circulation, or anoxic cerebral injury even after restoration of circulation. Nevertheless, when timely interventions are provided, a small proportion of patients (10.4% of all EMS-treated OHCA) recover to resume normal lives. The key therapeutic interventions that make the difference between life and death, metaphorically characterized as the 5 links in a chain of survival by the American Heart Association, include: (1) immediate recognition of cardiac arrest and activation of the EMS, (2) early CPR with emphasis on chest compression, (3) rapid defibrillation, (4) effective advanced life support, and (5) integrated postcardiac arrest care.3 Resuscitation science has undergone major advances since the origins of modern CPR >50 years ago.4 The field continues to be dynamic with emergence of new therapies such as therapeutic hypothermia5 and improvements in systems of care. However, many questions remain on issues such as optimum compression rate, efficacy of chest compression only CPR (CCCPR), dispatcher-assisted CPR, and benefits of postresuscitation measures such as hypothermia. A critical challenge also lies in the translation of resuscitation science into practice. To improve outcomes, each of the links in the chain of survival needs to be executed promptly and effectively. There remain several lacunae, which need to be overcome to develop an …

Sudden Cardiac Arrests, Automated External Defibrillators, and Medical Emergency Response Plans in Tennessee High Schools

Schools are important public locations of sudden cardiac arrest (SCA), and the American Heart Association (AHA) recommends medical emergency response plans (MERPs), which may include an automated external defibrillator (AED) in schools. The objective of this study was to determine the incidence of SCA and the prevalence of AEDs and MERPs in Tennessee high schools. Tennessee Secondary School Athletic Association member schools were surveyed regarding SCA on campus within 5 years, AED presence, and MERP characteristics. Of 378 schools, 257 (68%) completed the survey. There were 21 (5 student and 16 adult) SCAs on school grounds, yielding a 5-year incidence of 1 SCA per 12 high schools. An AED was present at 11 of 21 schools with SCA, and 6 SCA victims were treated with an AED shock. A linear increase in SCA frequency was noted with increasing school size (<500 students: 3.3% incidence, 500-1000: 6.5%, 1000-1500: 12.5%, ≥1500: 18.2%; P = 0.003). Of 257 schools, 71% had an MERP, 48% had an AED, and only 4% were fully compliant with AHA recommendations. Schools with a history of SCA were more likely to be compliant (19% vs. 3%, P = 0.011). The 5-year incidence of SCA in Tennessee high schools is 1 in 12, but increases to 1 in 7 for schools with more than 1000 students. Compliance with AHA guidelines for MERPs is poor, but improved in schools with recent SCA. Future recommendations should encourage the inclusion of AED placement in schools with more than 1000 students.

Marathon related cardiac arrest risk differences in men and women

ObjectiveTo determine the incidence of sudden cardiac arrest (SCA) and sudden cardiac death (SCD) in men and women.DesignRetrospective cohort study.SettingTwo popular urban 42 km marathons.Participants1982 to 2009 finishers.Assessment of risk...

Incidence and Predictors of Sudden Cardiac Arrest in Adults With Congenital Heart Defects Repaired Before Adult Life

Many adult survivors of repaired congenital heart disease (CHD) are at premature risk of death. Sudden cardiac arrest (SCA) is 1 of the leading causes of death but little is known about determinants for SCA in adults with repaired lesions. We sought to determine incidence and risk factors for SCA in a study population of 936 adults with previously repaired CHD who had completed follow-up at a single tertiary center during a mean period of 9 ± 7 years. Mean age at first examination in our institution was 21 ± 7 years. Diagnostic categories included tetralogy of Fallot (216), coarctation of the aorta (157), transposition complexes (99), single ventricle (55), and other CHD (409). During a total follow-up of 8,387 person-years, 22 patients (2.6 per 1,000 person-years) presented with SCA. Incidence of SCA varied widely between specific lesions; the highest incidence was observed in transposition complexes (10 per 1,000 person-years). Independent predictors of SCA were retrospectively identified using multivariate Cox proportional hazard modeling. Age at initial examination and severely impaired subaortic ventricular systolic function were independent risk factors for SCA (severe subaortic ventricular systolic dysfunction, adjusted hazard ratio 29, 95% confidence interval 11 to 72, p <0.001). SCA occurred in 23% of patients with severe subaortic ventricular systolic dysfunction versus 0.7% of patients with nonsevere decreased subaortic ventricular function (p <0.001). In conclusion, severe subaortic ventricular systolic dysfunction is a dominant multivariate predictor of SCA in an unselected population of adult survivors after surgery for CHD. Our data support the consideration of primary prevention strategies in these patients.

Sudden cardiac arrest

We appreciate Danyaal Raza’s letter,[1][1] which appeared in the Nov. 22 issue of CMAJ , regarding our paper “Socioeconomic status and incidence of sudden cardiac arrest.”[2][2] We also appreciate her suggestion that addressing low socioeconomic status itself may be instrumental in reducing

Evaluation of the Young Patient Resuscitated from Ventricular Fibrillation

Sudden cardiac death is defined by the World Health Organization as death occurring within the first 24 hours after the onset of symptoms. A more specific and probably more accurate definition of sudden death is a nontraumatic death that occurs within an hour of the onset of acute symptoms or during sleep. Autopsy studies have shown that approximately one-third of sudden deaths have noncardiac causes, with the remainder attributed to heart disease and classified as sudden cardiac arrest (SCA). Pre-existing heart disease may be recognized, but the time and mode of death are unexpected. Despite improvements in first response and resuscitation delivery, survival after SCA remains in the range of 4% to 5%. Most cases of SCA result from ventricular tachycardia, ventricular fibrillation, profound bradycardia, or pulseless electrical activity. Considerable variability in the reported incidence of SCA exists, with an incidence of less than 10 per 100,000 person-years in young healthy individuals (age <35 years) to more than 50 per 10,000 person-years in patients with structural heart

Socioeconomic status and incidence of sudden cardiac arrest

Low socioeconomic status is associated with poor cardiovascular health. We evaluated the association between socioeconomic status and the incidence of sudden cardiac arrest, a condition that accounts for a substantial proportion of cardiovascular-related deaths, in seven large North American urban populations. Using a population-based registry, we collected data on out-of-hospital sudden cardiac arrests occurring at home or at a residential institution from Apr. 1, 2006, to Mar. 31, 2007. We limited the analysis to cardiac arrests in seven metropolitan areas in the United States (Dallas, Texas; Pittsburgh, Pennsylvania; Portland, Oregon; and Seattle-King County, Washington) and Canada (Ottawa and Toronto, Ontario; and Vancouver, British Columbia). Each incident was linked to a census tract; tracts were classified into quartiles of median household income. A total of 9235 sudden cardiac arrests were included in the analysis. For all sites combined, the incidence of sudden cardiac arrestin the lowest socioeconomic quartile was nearly double that in the highest quartile (incidence rate ratio [IRR] 1.9, 95% confidence interval [CI] 1.8-2.0). This disparity was greater among people less than 65 years old (IRR 2.7, 95% CI 2.5-3.0) than among those 65 or older (IRR 1.3, 95% CI 1.2-1.4). After adjustment for study site and for population age structure of each census tract, the disparity across socioeconomic quartiles for all ages combined was greater in the United States (IRR 2.0, 95% CI 1.9-2.2) than in Canada (IRR 1.8, 95% CI 1.6-2.0) (p<0.001 for interaction). The incidence of sudden cardiac arrest at home or at a residential institution was higher in poorer neighbourhoods of the US and Canadian sites studied, although the association was attenuated in Canada. The disparity across socioeconomic quartiles was greatest among people younger than 65. The association between socioeconomic status and incidence of sudden cardiac arrest merits consideration in the development of strategies to improve survival from sudden cardiac arrest, and possibly to identify opportunities for prevention.