Out of Hospital Sudden Death in a Rural Population: Low Rates of ICD Underutilization Among Decedents.

BACKGROUND: Implantable cardioverter defibrillators (ICDs) reduce mortality in patients at risk for life-threatening arrhythmias. Implantation of ICDs in rural or economically disadvantaged populations is suspected to be low. This study examined Out of Hospital Premature Natural Death (OHPND) and electronic medical record (EMR) data to identify rates of non-implantation of ICDs among decedents in eastern North Carolina. METHODS: OHPND cases in 2016 were identified using mortality data and matched with EMRs. Those meeting criteria for ICD implantation based on chart review were adjudicated by two electrophysiologists to determine whether they qualified for implantation. Comorbidity burden was established using Charlson's Comorbidity Index (CCI). RESULTS: Out of 1316 OHPND cases, 967 (73.4%) had EMR records. Chart review identified 70 (7.2%) potential ICD candidates with a LVEF ≤35 of which 5 (7.1%) did not meet criteria because LVEF subsequently improved. Of the remaining 65 patients, 32 (49.2%) already received an ICD, and 33 patients (50.7%) met criteria but had not received one. Reasons for non-implantation included: limited life expectancy secondary to comorbidities, principally chronic kidney disease (CKD) (N = 11, 17%), physician non-adherence to guidelines (N = 9, 14%), loss to follow-up (N = 7, 11%), patient refusal (N = 5, 8%), and death before commencing medical therapy (N = 1, 2%). Among our cohort of 967 individuals who died unexpectedly, nine (0.9%) patients may have avoided death with an ICD. CONCLUSION: This study using decedent data shows low rates of ICD-underutilization in a rural population and emphasizes the role of advanced comorbidities such as CKD in ICD-underutilization.

Coronary Artery Disease and Atherosclerotic Risk Factors in a Population-Based Study of Sudden Death.

BACKGROUND: Sudden death is a public health problem with major impact on society. Coronary artery disease (CAD) is believed to underlie 60-80% of these deaths. While deaths from CAD have decreased in the recent decades, sudden death rates remain unacceptably high. OBJECTIVE: We aimed to assess the prevalence of CAD and its risk factors among 18-64-year-old adults in a population-based case registry of sudden deaths and compare them to a living population from the same geographical area. DESIGN: From 2013 to 2015, all sudden deaths among 18-64-year-old adults in Wake County, NC, were identified (n = 371). A comparison group was formed by randomly selecting individuals from an electronic health record repository of a major healthcare system in the area (N = 4218). MAIN MEASURES: Prevalence of CAD and its risk factors among cases of sudden death and living population across sex and age groups. Odds of sudden death associated with atherosclerotic risk factors and comorbidities. KEY RESULTS: CAD was present in 14.8% of sudden death cases. Among sudden death victims, most risk factors and comorbidities were more common in the older age group, except for obesity which was more common in younger cases, and diabetes which was equally prevalent in younger and older cases. Compared to living population, sudden death cases had higher prevalence of atherosclerotic risk factors across all gender and age groups. Sudden death cases had a numerically higher number of risk factors compared to living population, regardless of age group or presence of CAD. CONCLUSIONS: Coronary artery disease is not common among sudden death cases, but risk factors and comorbidities are prevalent. Our findings support the changing etiology of sudden death. In the absence of clinically diagnosed CAD, use of novel imaging modalities and biomarkers may identify high-risk individuals and lead to prevention of sudden death.

The effect of anxiety and depression on symptoms attributed to atrial fibrillation.

BACKGROUND: Symptoms attributed to atrial fibrillation (AF) are nonspecific, and it remains unclear what influences perception of symptoms. Anxiety or depression may be important in modulating perception of AF symptoms. However, few longitudinal studies have addressed this effect. METHODS: A total of 378 patients with AF completed anxiety and depression severity questionnaires as well as AF symptom and frequency severity questionnaires. Patients were offered treatment strategies including catheter ablation or antiarrhythmic or rate-controlling medications. Patients were followed at 3-month intervals and completed follow-up questionnaires including repeat assessment of anxiety, depression, and AF symptoms. A method of generalized estimating equations was used for longitudinal analyses. RESULTS: Analysis revealed that increased anxiety or depression was associated with increased AF symptom severity (AFSS), after adjusting for potential confounders. In both unadjusted and adjusted follow-up analyses, antiarrhythmic drug therapy or catheter ablation reduced AFSS (P < 0.001). However, none of anxiety severity, depression severity, or the perception of AF frequency severity improved significantly with AF treatment. CONCLUSIONS: Our results extend previous studies demonstrating that anxiety and depression are associated with worsened AFSS. Antiarrhythmic drug therapy or catheter ablation reduces AFSS but does not affect depression and anxiety symptoms. To achieve more comprehensive AF symptom relief, treatment of both AF and psychological comorbidities may be beneficial.

Brugada-type patterns are easily observed in high precordial lead ECGs in collegiate athletes.

BACKGROUND: Displacement of ECG leads can result in unwarranted findings. We assessed the frequency of Brugada-type patterns in athletes when precordial leads were purposely placed upward. METHODS: Four hundred ninety-one collegiate athletes underwent two ECGs: one with standard leads, one with V1 and V2 along the 2nd intercostal space. A positive Brugada-type pattern was defined as ST elevation in V1 or V2 consistent with a Type 1, 2, or 3 pattern in the high-lead ECG. A control group was comprised of 181 outpatients. RESULTS: No Type 1 patterns were seen. In 58 athletes (11.8%), a Brugada-type 2 or 3 pattern was observed. Those with Brugada-type 2 or 3 patterns were more likely male, taller, and heavier. In the control group, 18 (9.9%) had Brugada-type 2 or 3 patterns and were more likely male. CONCLUSIONS: Proper lead positioning is essential to avoid unwarranted diagnosis of a Brugada-type ECG, especially in taller, heavier male athletes.

Design of a Novel Intervention Model to Address Cardiovascular Health Disparities in the Rural Underserved Community of Phillips County Arkansas.

Devastating health-related disparities driven by an entanglement of factors disproportionately impact the underserved, low-wealth, and minority community of Phillips county (PC) in the Arkansas Delta Region (ADR). Cardiovascular disease continues to increase with widespread consequences on the local economy, health care systems, and population. Health care and community-based systems have been unsuccessful in reducing out-of-hospital cardiac death, particularly in the ADR, for many reasons. Herein, we share the strategy behind, planning, and goals of The Arkansas Lincoln Project, a novel neighborhood-based strategy bridging the gap between residents, social resources, and health care services in PC.

Mental Disorders, Substance Use Disorders, and Psychotropic Medication Use Among Sudden-Death Victims.

OBJECTIVE: The authors sought to estimate the prevalence of mental and substance use disorders and psychotropic medication prescriptions among working-age sudden-death victims. METHODS: Using a written protocol, the authors screened for sudden deaths attended by emergency medical services (EMS) in a large metropolitan county in North Carolina from March 1, 2013, to February 28, 2015. Sudden-death cases were adjudicated by three cardiologists. Mental health and chronic disease diagnoses and treatments were abstracted from EMS, medical examiner, toxicology, and autopsy reports and from clinical records for the past 5 years before death. RESULTS: Sudden death was identified for 399 adults ages 18-64 years, 270 of whom had available medical records. Most sudden-death victims were White (63%) and male (65%), had a comorbid condition such as hypertension or respiratory disease, and had a mean±SD age of death of 53.6±8.8 years. Most victims (59%) had at least one mental health or substance use disorder documented in a recent medical record; 76%-78% of victims with a mental disorder had a documented psychotropic medication prescription. However, fewer than one-half (41%) had a documented referral to a mental health professional. The most common diagnostic categories were depressive, anxiety, and alcohol-related disorders. Almost one-half (46%) of the victims had a recent psychotropic prescription, most commonly antidepressants (29%) and benzodiazepines (19%). CONCLUSIONS: Mental illness, substance use disorders, and psychotropic medication prescriptions were prevalent among sudden-death victims. The health care needs of these individuals may be better addressed by collaborative care for general medical and mental disorders.

A case-crossover analysis of the relationship of air pollution with out-of-hospital sudden unexpected death in Wake County, North Carolina (2013-2015).

Out-of-hospital sudden unexpected deaths are non-accidental deaths that occur without obvious underlying causes and may account for 10% of natural deaths before age 65. Short-term exposure to ambient air pollution is associated with all-cause (non-accidental) and cause-specific (e.g., cardiovascular) mortality, and with immediate exposures often yielding the highest magnitude risk estimates. Few studies have focused on short-term exposure to air pollution and sudden unexpected deaths. Using the University of North Carolina Sudden Unexpected Death in North Carolina population, we examine associations between short-term criteria air pollutant exposures with sudden unexpected deaths using a time-stratified case-crossover design, with data on criteria air pollutants from the Environmental Protection Agency's Air Quality System. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using conditional logistic regression with air pollutant exposures scaled to roughly inter-quartile ranges; models were adjusted for average temperature and relative humidity on event day and preceding 3 days. Potential for confounding by co-pollutants were examined in two pollutant models. ORs for PM2.5 at lag day 1 were elevated (adjusted OR for 5 µg/m3 increase: 1.17 (0.98, 1.40)), and were robust to co-pollutant adjustment. Elevated odds were observed for SO2 at lag day 0, and reduced odds for O3 at lag day 0; however, these associations were somewhat attenuated toward the null (SO2) or were not robust (O3) to co-pollutant adjustment. This analysis in a racially and socioeconomically diverse cohort, with a more inclusive definition of sudden unexpected death than is typically employed offers evidence that PM2.5 may be a clinically relevant trigger of sudden unexpected deaths in susceptible individuals.

Under-reporting of sudden unexpected death in epilepsy.

The identification and characterization of sudden unexpected deaths in epilepsy (SUDEP) may be improved, helping to optimize prevention and intervention. We set out to assess the frequency and demographic and clinical characteristics of SUDEP cases in a sudden death cohort. All out-of-hospital deaths were investigated from March 1, 2013 to February 28, 2015 in Wake County, NC, attended by the Emergency Medical Services. Cases were screened and adjudicated by three physicians to identify sudden death cases from any cause among free-living adults, aged 18-64. In total, 399 sudden death victims were identified during this two-year period. Seizure history, demographic and clinical characteristics, and healthcare utilization patterns were assessed from death records, emergency response scene reports, and medical records. Sudden death cases with a history of seizures were summarized by an experienced chart abstractor (SC) and adjudicated by an experienced neurologist (OD). We then compared demographic and clinical characteristics and healthcare utilization patterns of neurologist-identified SUDEP cases to other sudden death victims in our population-based registry of sudden death from any cause. SUDEP accounted for 5.3% of sudden deaths. However, seizures or complications of seizures were only considered the primary cause of death on death certificates in 1.5% of sudden deaths. SUDEP cases were more likely to have a history of alcohol abuse. Mental health disorders and a low level of medication compliance and healthcare utilization were common among SUDEP victims. SUDEP accounts for approximately 5.3% of sudden deaths from any cause in individuals aged between 18 and 64. Death certificates underestimate the burden of sudden death in epilepsy, attributing only 1.5% of sudden deaths to seizures or complications of seizures. Accurate documentation of epileptic disorders on death certificates is essential for the surveillance of SUDEP. Further, interventions that promote better use of medical services and patient engagement with healthy living practices may reduce sudden deaths in epilepsy.

Lipid Profiles in Out-of-Hospital Sudden Unexpected Death.

OBJECTIVE: To determine the association between serum lipid measurements and the occurrence of out-of-hospital sudden unexpected death (OHSUD). PATIENTS AND METHODS: We compared 139 OHSUD cases (43 female patients [30.9%]) and 968 controls (539 female patients [55.7%]) from Wake County, North Carolina, from March 1, 2013, through February 28, 2015. Individuals were included if they were aged 18 to 64 years and had lipid measurements in the 5 years before their death (cases) or the most recent health care encounter (controls). Covariates were abstracted from medical records for all subjects, and those with triglyceride (TG) levels greater than 400 mg/dL (to convert to mmol/L, multiply by 0.0259) were excluded for low-density lipoprotein (LDL)-related analyses. RESULTS: By linear regression using age- and sex-adjusted models, cases of OHSUD had lower adjusted mean total cholesterol (170.3±52.2 mg/dL vs 188.9±39.7 mg/dL; P<.001), LDL cholesterol (90.9±39.6 mg/dL vs 109.6±35.2 mg/dL; P<.001), and non-high-density lipoprotein (HDL) (121.6±49.8 mg/dL vs 134.3±39.6 mg/dL; P<.001) levels and a higher adjusted TG/HDL-C ratio (4.7±7 vs 3±2.7; P<.001) than did controls. By logistic regression using age- and sex-adjusted models, the odds of OHSUD were elevated per unit increase in TG/HDL-C ratio (1.08; 95% CI, 1.03-1.12). CONCLUSION: Out-of-hospital sudden unexpected death cases had more favorable levels of total cholesterol, LDL cholesterol, and non-HDL, possibly indicating a lack of association between traditional lipid cardiovascular risk factors and sudden unexpected death. A comparatively elevated TG/HDL-C ratio in cases may corroborate an evolving hypothesis of how vasoactive and prothrombotic remnant-like lipoprotein particles contribute to sudden unexpected death.

Exploring links between greenspace and sudden unexpected death: A spatial analysis.

Greenspace has been increasingly recognized as having numerous health benefits. However, its effects are unknown concerning sudden unexpected death (SUD), commonly referred to as sudden cardiac death, which constitutes a large proportion of mortality in the United States. Because greenspace can promote physical activity, reduce stress and buffer air pollutants, it may have beneficial effects for people at risk of SUD, such as those with heart disease, hypertension, and diabetes mellitus. Using several spatial techniques, this study explored the relationship between SUD and greenspace. We adjudicated 396 SUD cases that occurred from March 2013 to February 2015 among reports from emergency medical services (EMS) that attended out-of-hospital deaths in Wake County (central North Carolina, USA). We measured multiple greenspace metrics in each census tract, including the percentages of forest, grassland, average tree canopy, tree canopy diversity, near-road tree canopy and greenway density. The associations between SUD incidence and these greenspace metrics were examined using Poisson regression (non-spatial) and Bayesian spatial models. The results from both models indicated that SUD incidence was inversely associated with both greenway density (adjusted risk ratio [RR] = 0.82, 95% credible/ confidence interval [CI]: 0.69-0.97) and the percentage of forest (adjusted RR = 0.90, 95% CI: 0.81-0.99). These results suggest that increases in greenway density by 1 km/km2 and in forest by 10% were associated with a decrease in SUD risk of 18% and 10%, respectively. The inverse relationship was not observed between SUD incidence and other metrics, including grassland, average tree canopy, near-road tree canopy and tree canopy diversity. This study implies that greenspace, specifically greenways and forest, may have beneficial effects for people at risk of SUD. Further studies are needed to investigate potential causal relationships between greenspace and SUD, and potential mechanisms such as promoting physical activity and reducing stress.

Relation of Household Income to Incidence of Sudden Unexpected Death in Wake County, North Carolina.

The incidence of out-of-hospital sudden unexpected death (OHSUD) in a racially and socioeconomically diverse population has been inadequately studied. We collated all OHSUDs over a 24-month period among 18- to 64-year olds in Wake County, North Carolina, to investigate geographic and socioeconomic disparity in incidence of OHSUD. An electronic query of Wake County Emergency Medical Services (EMS) identified all EMS attended out-of-hospital deaths. After excluding trauma, expected deaths, and deaths occurring in non-free-living subjects, medical records and medical examiner's reports were reviewed by a committee of cardiologists to make the determination of OHSUD. Victims were geocoded to census tracts, and demographic and socioeconomic data were obtained from the 2014 American Community Survey and 2010 US Census. Incidence was examined by sociodemographic group with univariate analysis and multivariable regression. There were 397 OHSUDs, and 53% of census tracts had >1 event. The incidence of OHSUD was 64 of 100,000; 107 of 100,000 among blacks; and 60 of 100,000 among whites. Census tracts with >1 OHSUD had a higher population of blacks, a greater proportion unmarried, a lower median household income, and a greater proportion residing in a rural area. Only median household income remained a significant predictor of OHSUD after adjustment in multivariable analysis. Low median household income of a community portends a higher incidence of sudden death. In conclusion, interventions to reduce the incidence of sudden death need to be developed with these specific communities in mind.

Estimated incidence and risk factors of sudden unexpected death.

OBJECTIVE: In this manuscript, we estimate the incidence and identify risk factors for sudden unexpected death in a socioeconomically and racially diverse population in one county in North Carolina. Estimates of the incidence and risk factors contributing to sudden death vary widely. The Sudden Unexpected Death in North Carolina (SUDDEN) project is a population-based investigation of the incidence and potential causes of sudden death. METHODS: From 3 March 2013 to 2 March 2014, all out-of-hospital deaths in Wake County, North Carolina, were screened to identify presumed sudden unexpected death among free-living residents between the ages of 18 and 64 years. Death certificate, public and medical records were reviewed and adjudicated to confirm sudden unexpected death cases. RESULTS: Following adjudication, 190 sudden unexpected deaths including 122 men and 68 women were identified. Estimated incidence was 32.1 per 100 000 person-years overall: 42.7 among men and 22.4 among women. The majority of victims were white, unmarried men over age 55 years, with unwitnessed deaths at home. Hypertension and dyslipidaemia were common in men and women. African-American women dying from sudden unexpected death were over-represented. Women who were under age 55 years with coronary disease accounted for over half of female participants with coronary artery disease. CONCLUSIONS: The overall estimated incidence of sudden unexpected death may account for approximately 10% of all deaths classified as 'natural'. Women have a lower estimated incidence of sudden unexpected death than men. However, we found no major differences in age or comorbidities between men and women. African-Americans and young women with coronary disease are at risk for sudden unexpected death.

Minimally Symptomatic Atrial Fibrillation Patients Derive Significant Symptom Relief Following Rate Control or Rhythm Control Therapy.

BACKGROUND: It can be challenging to convince asymptomatic to minimally symptomatic patients to pursue treatment of their atrial fibrillation (AF). We hypothesized that once in sinus rhythm, asymptomatic to minimally symptomatic patients would realize they were compensating for moderate symptoms, and that we could quantify this via the Canadian Cardiovascular Society Severity of AF (CCS-SAF) score. METHODS: All patients in our study come from the Symptom Mitigation in Atrial Fibrillation (SMART) study. Upon enrollment all patients were assigned a CCS-SAF score. Patients receiving a CCS-SAF score of 0 or 1 that elected to pursue intervention were contacted by phone and asked about their symptoms post-intervention as compared to pre-intervention. Paired t-test was used for analysis. RESULTS: Out of 800 patients in the SMART study to date, 48 patients have qualified for our phone survey and presented for follow-up in our clinic. In our cohort, the revised pre-intervention CCS-SAF score was 1.69 ± 1.36 and the post-intervention CCS-SAF score was 0.52 ± 0.80. Thirty-seven patients reported symptom improvement; those who improved were on average 72.4% improved from baseline. CONCLUSIONS: We conclude asymptomatic to minimally symptomatic AF patients benefit from therapy and should be offered intervention despite lack of symptoms.

Accuracy of patient perception of their prevailing rhythm: a comparative analysis of monitor data and questionnaire responses in patients with atrial fibrillation.

BACKGROUND: Atrial fibrillation (AF) guidelines recommend that symptom relief be a primary goal in management. However, patient perception of their prevailing rhythm is often inaccurate, complicating symptom-targeted treatment. OBJECTIVE: The purpose of this study was to evaluate the accuracy of patient perception of their prevailing rhythm and identify factors that predict inaccuracies. METHODS: Demographic and health status data were captured by questionnaires for 458 outpatients with documented AF. AF burden (%) was captured by 1-week continuous heart monitors. Patients estimated the length and frequency of their AF episodes by completing the AF Symptom Severity questionnaire. Patient reports were compared to AF burden, and outliers were identified and broken into 2 groups: patients with AF burden <10% who indicated near-continuous AF (overestimators) and patients with AF burden >90% who estimated little to no AF (underestimators). Multinomial logistic regression was used to identify predictors of inaccuracies (over- or underestimators). RESULTS: By continuous monitor, 15% of patients were found to be over- or underestimators. Persistent AF, female sex, older age, anxiety, and depression were predictive of inaccurate patient perception. Persistent AF, female sex, and older age were predictive of underestimating, while mood disorders (anxiety and depression) were predictive of overestimating. The prevalence of underestimators was nearly twice that of overestimators. CONCLUSION: Sex, age, and mood disorders are among factors that lead to inaccurate patient perception of their prevailing rhythm in patients with AF. Such modulating factors should be considered when evaluating treatment strategies. Consideration should be given to more liberal use of heart monitors in these patient populations to better target therapy.

Effectiveness of atrial fibrillation monitor characteristics to predict severity of symptoms of atrial fibrillation.

The goal of treatment for atrial fibrillation (AF) is often to control symptoms. It remains unclear whether targets for treatment such as AF rate or AF burden are correlated with AF symptom severity. Two hundred eighty-six patients completed a questionnaire of their general health and well-being, including a detailed AF symptom assessment immediately followed by a 7-day continuous monitor. AF characteristics assessed from the monitor included AF burden, AF rate, sinus rhythm rate, frequency and severity of pauses, and premature atrial contraction or premature ventricular contraction burden. Characteristics were analyzed separately for patients with paroxysmal or persistent AF. Symptom severity was assessed using the University of Toronto Atrial Fibrillation Severity Scale. Monitor characteristics were compared with AF symptom severity. The mean age of the cohort was 61.8 years and the majority of subjects were male (65.4%). Co-morbidities included hypertension (64.5%), sleep apnea (38.4%), congestive heart failure (19.6%), and diabetes (16.4%). In those with persistent or paroxysmal AF, there were no significant predictors of AF symptom severity. Specifically, heart rate in AF or sinus rhythm, AF burden, or premature atrial contraction or premature ventricular contraction burden was not predictive of AF symptom severity. After adjusting for potential cofounders (including age, gender, and co-morbidities), these findings persisted. In conclusion, there is no value in using AF monitor characteristics to predict symptoms in patients with AF.

Evaluation of an integrated bipolar and unipolar ablation device.

OBJECTIVE: Bipolar lesion creation is accepted as the most effective method to create transmural atrial ablations. However, the creation of an ablation pattern on the left and the right atrium with current bipolar devices is difficult on the beating heart. We have evaluated a novel integrated ablation device that creates both bipolar and unipolar lesions in a linear pattern on the beating porcine heart. METHODS: Using six porcine models, we evaluated the effectiveness of creating beating heart ablation lesions by transmurality and conduction block. Isolating lesions were created on the left and right atria of the beating porcine heart. After we created sequential bipolar and unipolar lesions, we confirmed conduction block and examined the lesion depth histologically. RESULTS: Linear lesions were created successfully on the surface of the beating porcine heart. Conduction block at 20 mV was confirmed at all isolated areas, and 96.4% of the lesion sections had full thickness and were transmural at histology. CONCLUSIONS: This device enables unipolar and bipolar lesion creation in a linear and low-profile manner, enabling effective creation of a biatrial lesion pattern on the epicardial surface of the beating heart.

Effect of left ventricular diastolic dysfunction on outcomes of atrial fibrillation ablation.

Left ventricular diastolic dysfunction (LVDD) is an important pathogenic factor for atrial fibrillation (AF). There are few data on the effect of LVDD on recurrence of AF after catheter ablation. A cohort of 124 patients (59.9 ± 11.7 years, 73.9% male, and 55% with paroxysmal AF) with recalcitrant AF and normal left ventricular systolic function (left ventricular ejection fraction ≥50%) undergoing ablation was studied. Each patient underwent transthoracic echocardiography, and LVDD was meticulously graded using rhythm-independent (AF or sinus rhythm) transmitral and tissue Doppler parameters. Patients underwent catheter ablation of AF using a stepwise protocol. All patients were followed up at 3, 6, and 12 months with recurrent AF (>30 seconds) captured by electrocardiography and/or 7-day monitor. Kaplan-Meier survival analysis and Cox proportional hazards model were used. There was no LVDD in 72 patients (58%), whereas 33 (26.6%), 10 (8.1%), and 9 (7.3%) patients had grades 1, 2, and 3 LVDD, respectively. AF recurred in 49 patients (39.5%) with median time to recurrence of 248 days. Patients with higher grade of LVDD were increasingly more likely to have recurrence (37.5% for no LVDD and 30.3%, 60%, and 66.7% for grades 1, 2, and 3 LVDD, respectively). Significant LVDD (grade 2 or 3) was an independent predictor of recurrence (hazard ratio 2.6, p = 0.009) after adjusting for persistent (vs paroxysmal) AF and left atrial volume. In conclusion, patients with more severe LVDD have a higher risk of AF recurrence after catheter ablation. These patients may derive less benefit from ablation or may require a more extensive ablation approach.

Sudden Unexpected Death in North Carolina (SUDDEN): methodology review and screening results.

OBJECTIVES: This paper describes the methodology for a prospective, community-based study of sudden unexpected death in Wake County, North Carolina. METHODS: From 1 March to 29 June 2013, data of presumed cardiac arrest cases were captured from Wake County Emergency Medical Services. Participants were screened into the presumed sudden unexpected death group based on specific and sequential screening criteria, and medical and public records were collected for each participant in this group. A committee of independent cardiologists reviewed all data to determine final inclusion/exclusion of each participant into registry. RESULTS: We received 398 presumed cardiac arrest referrals. Of these, 105 participants, age 18-65 years old, were identified as presumed sudden unexpected deaths. The primary reason for exclusion was survival to hospital (38%). Ninety-five per cent of participants in the presumed sudden unexpected death group experienced an unwitnessed death. Hypertension was present in almost 50%, while dyslipidaemia and diabetes mellitus were present in almost 25% of the same group. In addition, the presumed sudden unexpected death group includes 67.6% males (95% CI 58 to 76) whereas the control group only included 58.9% (95% CI 46 to 55) males. CONCLUSIONS: Participant identification and data collection processes identify presumed sudden unexpected death cases and secure medical and public data for screening and final adjudication. The study infrastructure developed in Wake County will allow its expansion to other counties in North Carolina. Preliminary data indicate the study presently focuses on a population demographically representative of North Carolina.