A Clinical Perspective on Sudden Cardiac Death

Biomarker Periodic Repolarization Dynamics Indicates Enhanced Risk for Arrhythmias and Sudden Cardiac Death in Myocardial Infarction in Pigs

BACKGROUND

Periodic repolarization dynamics (PRD) is an electrocardiographic biomarker that captures repolarization instability in the low frequency spectrum and is believed to estimate the sympathetic effect on the ventricular myocardium. High PRD indicates an increased risk for postischemic sudden cardiac death (SCD). However, a direct link between PRD and proarrhythmogenic autonomic remodeling has not yet been shown.

METHODS AND RESULTS

We investigated autonomic remodeling in pigs with myocardial infarction (MI)-related ischemic heart failure induced by balloon occlusion of the left anterior descending artery (n=17) compared with pigs without MI (n=11). Thirty days after MI, pigs demonstrated enhanced sympathetic innervation in the infarct area, border zone, and remote left ventricle paralleled by altered expression of autonomic marker genes/proteins. PRD was enhanced 30 days after MI compared with baseline (pre-MI versus post-MI: 1.75±0.30 deg2 versus 3.29±0.79 deg2, P<0.05) reflecting pronounced autonomic alterations on the level of the ventricular myocardium. Pigs with MI-related ventricular fibrillation and SCD had significantly higher pre-MI PRD than pigs without tachyarrhythmias, suggesting a potential role for PRD as a predictive biomarker for ischemia-related arrhythmias (no ventricular fibrillation versus ventricular fibrillation: 1.50±0.39 deg2 versus 3.18±0.53 deg2 [P<0.05]; no SCD versus SCD: 1.67±0.32 deg2 versus 3.91±0.63 deg2 [P<0.01]).

CONCLUSIONS

We demonstrate that ischemic heart failure leads to significant proarrhythmogenic autonomic remodeling. The concomitant elevation of PRD levels in pigs with ischemic heart failure and pigs with MI-related ventricular fibrillation/SCD suggests PRD as a biomarker for autonomic remodeling and as a potential predictive biomarker for ventricular arrhythmias/survival in the context of MI.

Preparticipation Cardiac Evaluation from the Pediatric Perspective

Each year millions of children and adolescents undergo sports preparticipation evaluations (PPEs) before participating in organized sports. A primary aim of the PPE is to screen for risk factors associated with sudden cardiac death. This article is designed to summarize the current thoughts on the PPE with a specific slant toward the pediatric and early adolescent evaluation and how these evaluations may differ from those in adults.

Incidence of Sudden Cardiac Death in Low- and Middle-Income Countries: A Systematic Review of Cohort Studies

Sudden cardiac death (SCD) is a leading cause of mortality worldwide and, in recent years, has become an urgent public health concern in low- and middle-income countries (LMICs). Data from LMICs, however, remains limited. As such, the aim of this article is to systematically review the current literature on the incidence of SCD in LMICs to inform policymakers and identify potential research gaps. A search of PubMed and Embase was utilized to capture the targeted condition, outcome, and setting. Only peer-reviewed cohort studies in LMICs reporting SCD incidence estimates in the general population of individuals aged ≥1 year were eligible for selection. Papers providing incidence data for specific types of SCD, including sudden coronary death or death from sudden cardiac arrest, were also included. After deduplication, 1941 citations were identified and screened. Seven studies representing four countries-Cameroon, China, India, and Iran-met the criteria for inclusion and were considered in our analysis. The crude incidence rate for SCD ranged from 19.9 to 190 cases per 100,000 person-years, while age-adjusted rates ranged from 33.6 to 230 cases per 100,000 person-years. There was notable variability in methods utilized to ascertain SCD cases. These findings suggest that the incidence of all-cause SCD in LMICs and may exceed that of high-income countries; however, observed disparities may be partly attributable to differences in case ascertainment methods. Additional research is needed to better understand the true incidence of SCD in developing countries. It is crucial that future studies across regions utilize standard diagnostic criteria and methodology for identifying SCD, which would provide a framework by which to compare outcomes between settings.

[Forensic medical characteristic of prevalence and structure of sudden juveniles' death in Moscow Region and St. Petersburg]

THE AIM OF THE STUDY

Was to compare the prevalence and structure of sudden death from cardiovascular diseases (CVD) in the structure of nonviolent death in Moscow Region as a representative of the large region and St. Petersburg as a city of federal importance. Frequency and structure of this parameter, as well as its dynamics were analyzed. The comparison of obtained results with data of Federal State Statistics Service was done. Nonparametric analysis of the initial data has been conducted. Clustering and visualization, based on the following parameters of initial sample, have been done: «death rate from CVD in the structure of nonviolent death», «morbidity rate», «incomes» and «unemployment rate». Correlation dependences between death rate from CVD according to the Form №42 and mentioned parameters of medical and social state of the subject have been determined. Dependences between sudden death rate from CDV and a number of medical and social parameters have been established.

Acute Impact of Fine Particulate Air Pollution on Cardiac Arrhythmias in a Population‐Based Sample of Adolescents: The Penn State Child Cohort

Background

Fine particulate (fine particles with aerodynamic diameters ≤2.5 μm [PM 2.5 ]) exposure has been associated with a risk of cardiac arrhythmias in adults. However, the association between PM 2.5 exposure and cardiac arrhythmias in adolescents remains unclear.

Methods and Results

To investigate the association and time course between PM 2.5 exposure with cardiac arrhythmias in adolescents, we analyzed the data collected from 322 adolescents who participated in the PSCC (Penn State Child Cohort) follow‐up examination. We obtained individual‐level 24‐hour PM 2.5 concentrations with a nephelometer. Concurrent with the PM 2.5 measure, we obtained 24‐hour ECG data using a Holter monitor, from which cardiac arrhythmias, including premature atrial contractions and premature ventricular contractions (PVCs), were identified. PM 2.5 concentration and numbers of premature atrial contractions/PVCs were summarized into 30‐minute‐based segments. Polynomial distributed lag models within a framework of a negative binomial model were used to assess the effect of PM 2.5 concentration on numbers of premature atrial contractions and PVCs. PM 2.5 exposure was associated with an acute increase in number of PVCs. Specifically, a 10 μg/m 3 increase in PM 2.5 concentration was associated with a 2% (95% CI, 0.4%–3.3%) increase in PVC counts 0.5 to 1.0, 1.0 to 1.5, and 1.5 to 2.0 hours after the exposure. Cumulatively, a 10 μg/m 3 increment in PM 2.5 was associated with a 5% (95% CI, 1%–10%) increase in PVC counts within 2 hours after exposure. PM 2.5 concentration was not associated with premature atrial contraction.

Conclusions

PM 2.5 exposure was associated with an acute increased number of ventricular arrhythmias in a population‐based sample of adolescents. The time course of the effect of PM 2.5 on ventricular arrhythmia is within 2 hours after exposure.

Burden of influenza in adults with cardiac arrest admissions in Australia

BACKGROUND

Cardiac arrest is the least preventable burden of cardiovascular disease, as treatment depends on timely resuscitation. The incidence of sudden cardiac arrest (SCA) is high, contributing 10-20% of cardiovascular mortality globally. The influenza vaccine reduces the risk of acute cardiovascular events. Little is known about the relationship of influenza infection to cardiac arrest.

METHODS

This study aimed to determine the estimated rate of SCA hospitalisations attributable to influenza in Australian adults. A generalised-additive statistical model was applied in the study. Weekly counts of laboratory-confirmed influenza notifications were used as independent variables in the model.

RESULTS

Our estimates showed that the yearly rate of SCA hospitalisations varied, and a significant association with influenza was observed in some years in older adults aged 65 years and over. On average, the annual estimated SCA hospitalisations rate due to influenza in adults aged 50-64 years and ≥ 65 years were 0.7 (95%CI: 0.4, 1.1) and 5.3 (95%CI: 4.4, 6.2) per 100,000 population, respectively.

CONCLUSION

The association between influenza and SCA is evident in adults and the disease burden is significant in older people. Prevention of influenza by vaccination may reduce SCA.

Pattern of sudden cardiac deaths

BACKGROUND AND OBJECTIVE

Sudden cardiac death can be defined as a sudden, unexpected death caused by loss of heart function. Notwithstanding major developments in the diagnosis and treatment of heart disease, it remains the major contributing factor for deaths. This considers the pattern of sudden cardiac deaths.Methodology: This prospective study was conducted on all cases subjected to medico-legal autopsy in the forensic medicine department at a tertiary care hospital for a period of 18 months. All sudden cardiac deaths satisfying the WHO criteria were included. Unknown cases and bodies in advanced stage of decomposition were excluded.

RESULTS

Sudden cardiac deaths accounted for 55% (82 cases) of 149 cases of sudden natural deaths and 6.5% of total autopsies conducted. The age group most commonly affected by sudden cardiac death ranged from 31 to 50 years. The majority of the cadavers had 90-95% degree of stenosis of left anterior descending artery, 70-80% of right coronary artery and 60-70% left circumflex artery. Coronary insufficiency was the major cause for sudden cardiac deaths with a total of 53 (64.63%) cases.

CONCLUSION

Sudden cardiac deaths accounted for 6.5% of all the autopsies conducted and males outnumbered females with M:F ratio of 10.7:1, with mean age of 44.5 ± 12.63 years. The largest number - 60.97% - were aged between 31 and 50 years. Coronary insufficiency accounted for 64.63% of sudden cardiac deaths.

The role of metabolic syndrome in sudden cardiac death risk: Recent evidence and future directions

Metabolic syndrome (MetS) is a frequent condition whose deleterious effects on the cardiovascular system are often underestimated. MetS is nowadays considered a real pandemic with an estimated prevalence of 25% in general population. Individuals with MetS are at high risk of sudden cardiac death (SCD) as this condition accounts for 50% of all cardiac deaths in such a population. Of interest, recent studies demonstrated that individuals with MetS show 70% increased risk of SCD even without previous history of coronary heart disease (CHD). However, little is known about the interplay between the two conditions. MetS is a complex disease determined by genetic predisposition, unhealthy lifestyle and ageing with deleterious effects on different organs. MetS components trigger a systemic chronic low-grade pro-inflammatory state, associated with excess of sympathetic activity, cardiac hypertrophy, arrhythmias and atherosclerosis. Thus, MetS has an important burden on the cardiovascular system as demonstrated by both preclinical and clinical evidence. The aim of this review is to summarize recent evidence concerning the association between MetS and SCD, showing possible common aetiological processes, and to indicate prospective for future studies and therapeutic targets.

Utilization and cost-effectiveness of school and community center AED deployment models in Canadian cities

BACKGROUND

The optimal locations and cost-effectiveness of placing automated external defibrillators(AEDs) for out-of-hospital cardiac arrest(OHCAs) in urban residential neighbourhoods are unclear.

METHODS

We used prospectively collected data from 2016 to 2018 from the British Columbia OHCA Registry to examine the utilization and cost-effectiveness of hypothetical AED deployment in municipalities with a population of over 100 000. We geo-plotted OHCA events using seven hypothetical deployment models where AEDs were placed at the exteriors of public schools and community centers and fetched by bystanders. We calculated the "radius of effectiveness" around each AED within which it could be retrieved and applied to an individual prior to EMS arrival, comparing automobile and pedestrian-based retrieval modes. For each deployment model, we estimated the number of OHCAs within the "radius of effectiveness".

RESULTS

We included 4017 OHCAs from ten urban municipalities. The estimated radius of effectiveness around each AED was 625 m for automobile and 240m for pedestrian retrieval. With AEDs placed outside each school and community center, 2567(64%) and 605(15%) of OHCAs fell within the radii of effectiveness for automobile and pedestrian retrieval, respectively. For each AED, there was an average of 1.20-2.66 and 0.25-0.61 in-range OHCAs per year for automobile retrieval and pedestrian retrieval, respectively, depending on the deployment model. All of our proposed surpassed the cost-effectiveness threshold of 0.125 OHCA/AED/year provided >5.3-11.6% in-range AEDs were brought-to-scene.

CONCLUSIONS

The systematic deployment of AEDs at schools and community centers in urban neighbourhoods may result in increased application and be a cost-effective public health intervention.

Upper extremity dysfunctions in patients with cardiac implantable electronic devices: a systematic review

Background/Aims

The prevalence of cardiac implantable electronic devices has risen considerably during recent years. This has revolutionised the treatment of cardiac arrhythmias, which in turn reduced the incidence of sudden cardiac death. There are several complications associated with cardiac implantable electronic device implantation. Upper extremity dysfunction is one of the complications associated with this procedure and it should be addressed, since it can affect activities of daily living. This systematic review analysed the prevailing evidence pertaining to the common upper extremity dysfunctions associated with receiving a cardiac implantable electronic device.

Methods

A comprehensive literature search was conducted using PubMed, Cochrane Central Register of Controlled Trials, EMBASE (through Cochrane) and Google Scholar for original research published in the English language. The Rayyan QCRI web application was used for study selection and the decision-making process. PRISMA guidelines were used to conduct and report this review. The methodological quality of the included studies was appraised using the Newcastle–Ottawa Scale and Joanna Briggs Institute critical appraisal tool for analytic cross-sectional studies and case reports.

Results

This systematic review included eight studies with a total of 696 participants. The most common upper extremity dysfunctions associated with receiving a cardiac implantable electronic device were pain and limitation of shoulder range of motion. Limitation of range of motion could be persisted even in the long term after having a cardiac implantable electronic device implanted.

Conclusions

Contributing factors of upper extremity dysfunctions included size of the device, pectoral site of implantation and upper extremity immobilisation practices. Upper extremity dysfunction is an overlooked complication, as it received a relatively low priority, although it may negatively impact quality of life.

Mediterranean Diet Score, Dietary Patterns, and Risk of Sudden Cardiac Death in the REGARDS Study

Background

Sudden cardiac death (SCD) is a common cause of death in the United States. Few previous studies have investigated the associations of diet scores and dietary patterns with risk of SCD. We investigated the associations of the Mediterranean diet score and various dietary patterns with risk of SCD in participants in the REGARDS (Reasons for Geographic and Racial Differences in Stroke) study cohort.

Methods and Results

Diet was assessed with a food frequency questionnaire administered at baseline in REGARDS. The Mediterranean diet score was derived based on the consumption of specific food groups considered beneficial or detrimental components of that diet. Dietary patterns were derived previously using factor analysis, and adherence to each pattern was scored. SCD events were ascertained through regular contacts. Cox proportional hazards regression was used to examine the risk of SCD events associated with the Mediterranean diet score and adherence to each of the 5 dietary patterns overall and stratifying on history of coronary heart disease at baseline. The analytic sample included 21 069 participants with a mean 9.8±3.8 years of follow‐up. The Mediterranean diet score showed a trend toward an inverse association with risk of SCD after multivariable adjustment (hazard ratio [HR] comparing highest with lowest group, 0.74; 95% CI, 0.55–1.01; P_trend=0.07). There was a trend toward a positive association of the Southern dietary pattern with risk of SCD (HR comparing highest with lowest quartile of adherence, 1.46; 95% CI, 1.02–2.10; P_trend=0.06).

Conclusions

In REGARDS participants, we identified trends toward an inverse association of the Mediterranean diet score and a positive association of adherence to the Southern dietary pattern with risk of SCD.

Testing a nurse-led, pre-implantation educational intervention for primary prevention implantable cardioverter-defibrillator candidates: a randomized feasibility trial

AIMS

Implantable cardioverter-defibrillators (ICDs) deliver therapy for life-threatening arrhythmias. Evidence suggests that ICD candidates have misconceptions regarding ICD therapy and unmet information needs. We undertook a pilot feasibility trial comparing a nurse-led educational intervention plus standard care, vs. standard pre-ICD implantation care. Secondary aims included examination of anxiety, quality of life, and shock anxiety.

METHODS AND RESULTS

Implantable cardioverter-defibrillator candidates were consented and randomized to standard pre-ICD implantation care vs. standard care plus a nurse-led educational intervention. The primary feasibility outcomes included: recruitment rate, consent rate, randomization rate, proportion of participants able to complete all questionnaires, time to deliver intervention, and intervention topics completion. At baseline, demographic and Patient-Reported Outcomes Measurement Information System (PROMIS) anxiety scores were collected. Four weeks post-ICD implantation, participants completed the PROMIS, Florida Patient Acceptance Survey (FPAS), and Florida Shock Anxiety Scale (FSAS). Twenty patients consented (10 per group). Feasibility targets were achieved for all but two outcomes: consent rate was 87% vs. 95% target, and completion of data collection measures was 85% vs. 90% target. Consent rate was lower than expected as one patient declined, and two could not be approached. Completion rate was lower than expected as two patients were lost to follow-up, and one did not receive an ICD during the study period, leading to incomplete post-implantation survey collections.

CONCLUSION

The results demonstrate the feasibility of conducting a trial comparing a nurse-led pre-implantation educational intervention to standard care in an outpatient setting. Further study to evaluate the effectiveness of this intervention on patient-reported outcomes is warranted.

Cardiac arrest in a patient with trichorhinophalangeal syndrome and dilated cardiomyopathy

A 44-year-old woman with known trichorhinophalangeal syndrome presented with an unheralded out of hospital cardiac arrest. Transthoracic echocardiography showed severe left ventricular systolic dysfunction with an ejection fraction <25% and cardiac MRI confirmed a diagnosis of congenital non-ischaemic dilated cardiomyopathy. The case highlights a very rare syndrome, it is previously unknown association with dilated cardiomyopathy and the possible benefit of cardiac screening for patients with known trichorhinophalangeal syndrome.

Availability and Utilization of Automated External Defibrillators in New York State Schools

Background: Use of automated external defibrillators (AEDs) in out-of-hospital cardiac arrests (OHCAs) improve survival. Professional health organizations recommend that AEDs be available in crowded places, including schools but currently only 18 US states require them. Sudden cardiac arrest (SCA) research in the school-age population has largely focused on school sub-groups, leaving out the majority of US students and adults working in schools. New York State (NYS) has one of the largest student populations in the US. Our objective was to gain epidemiologic data on SCA across a variety of school levels and examine the availability and utilization of AEDs in a state that requires them. Methods: This was an observational, cross-sectional study utilizing an electronic survey. We included NYS school nurses and collected electronic surveys in January-March, 2018. We analyzed demographic data of school characteristics, SCA occurrences and AED use and availability. Results: Of 876 respondents (36.1% response rate), 71 (8.2%) reported SCAs, with 41 occurring in adults. AEDs were deployed in 59 of 71 (84.3%) events, 40 individuals had long-term survival. Most SCAs occurred in middle-schools. School size or number of AEDs/school had no bearing on short-term or long-term survival. AEDs were widely available in private schools, though this was not required by state law. Conclusions: Our data suggest a need for more comprehensive examination of SCA in US schools. Research comparing the availability and utilization of school AEDs between states that do and do not require them is needed and may have important clinical and policy implications for SCA emergency preparedness in US schools.

Circadian Rhythms of Early Afterdepolarizations and Ventricular Arrhythmias in a Cardiomyocyte Model

Sudden cardiac arrest is a malfunction of the heart's electrical system, typically caused by ventricular arrhythmias, that can lead to sudden cardiac death (SCD) within minutes. Epidemiological studies have shown that SCD and ventricular arrhythmias are more likely to occur in the morning than in the evening, and laboratory studies indicate that these daily rhythms in adverse cardiovascular events are at least partially under the control of the endogenous circadian timekeeping system. However, the biophysical mechanisms linking molecular circadian clocks to cardiac arrhythmogenesis are not fully understood. Recent experiments have shown that L-type calcium channels exhibit circadian rhythms in both expression and function in guinea pig ventricular cardiomyocytes. We developed an electrophysiological model of these cells to simulate the effect of circadian variation in L-type calcium conductance. In our simulations, we found that there is a circadian pattern in the occurrence of early afterdepolarizations (EADs), which are abnormal depolarizations during the repolarization phase of a cardiac action potential that can trigger fatal ventricular arrhythmias. Specifically, the model produces EADs in the morning, but not at other times of day. We show that the model exhibits a codimension-2 Takens-Bogdanov bifurcation that serves as an organizing center for different types of EAD dynamics. We also simulated a two-dimensional spatial version of this model across a circadian cycle. We found that there is a circadian pattern in the breakup of spiral waves, which represents ventricular fibrillation in cardiac tissue. Specifically, the model produces spiral wave breakup in the morning, but not in the evening. Our computational study is the first, to our knowledge, to propose a link between circadian rhythms and EAD formation and suggests that the efficacy of drugs targeting EAD-mediated arrhythmias may depend on the time of day that they are administered.

Evaluating the Utility of Toxicologic Analysis in Pediatric Out-of-Hospital Cardiac Arrest

BACKGROUND

The cause of a pediatric out-of-hospital cardiac arrest (OHCA) may go unexplained in the emergency department setting but can be secondary to a toxicologic etiology. It is unclear how toxicologic screens are used in the postarrest period after a pediatric OHCA.

OBJECTIVES

The primary objectives are to describe 1) when the toxicology screen (urine and serum) is used, 2) patient characteristics, and 3) toxicology screen results. We hypothesized that toxicology screens are frequently used but that positive results are uncommon.

METHODS

This was a retrospective study of pediatric OHCA patients admitted to the Penn State Health Children's Hospital pediatric intensive care unit as transfers from the emergency department between January 1, 2011 and May 31, 2018. We reviewed the electronic health record and evaluated for toxicology screen completion, patient characteristics, and toxicology screen results.

RESULTS

One hundred forty-one patients had a pediatric OHCA. Sixty-three (44.7%) patients did not have a toxicology screen completed. A toxicology screen had a higher completion rate for children >11 years of age (n = 26 [78.8%]; p = 0.0024), and in unwitnessed arrests (n = 48 [66.7%]; p = 0.0052). Four cases (5.1%) revealed the presence of substances that were not administered by a medical provider or were illicit.

CONCLUSION

Our study found that in pediatric OHCA, toxicologic screens were completed but were not routinely sent in our institution. There may be factors such as clinician bias or the severity of a patient's illness that impact the approach to toxicologic screening in pediatric OHCA. In addition to the history and physical examination, emergency physician and pediatric intensivists should consider routinely sending toxicologic screens to assist in uncovering any accidental or malicious explanation for the event.

Assessment of Tp-e interval and Tp-e/QT ratio in patients with human immunodeficiency virus

OBJECTIVE

Sudden cardiac death (SCD) plays an important part in all-cause mortality in patients infected with human immunodeficiency virus (HIV). The T-peak to T-end (Tp-e) interval, corrected Tp-e (Tp-ec) interval, and Tp-e/QT ratio on the ECG are parameters used to stratify risk for SCD. The objective of this study was to investigate the differences between HIV-infected patients and healthy individuals in terms of Tp-e interval, Tp-ec interval, and Tp-e/QT ratio, as well as other influencing factors.

METHODS

Ninety-eight HIV-infected patients and 62 healthy controls were included in this prospective case-control study. Tp-e interval, Tp-ec interval, and Tp-e/QT ratio were measured in all participants. Echocardiographic examination and routine laboratory analysis were performed. In addition, CD4 T-cell count and HIV RNA levels were assessed in HIV-infected patients.

RESULTS

All baseline characteristics were comparable in both groups. The median survival of those living with HIV was 20.63 months; 53% of them had controlled viral load, and 74% were receiving antiretroviral therapy. Mean baseline CD4 T-cell count was 409. In HIV-infected patients, the Tp-e interval and Tp-ec interval were prolonged, and the Tp-e/QT ratio was higher (p<0.001, p<0.001 and p=0.021, respectively). In bivariate and partial correlation analyses, there was a negative correlation between CD4 T-cell level and Tp-e interval, Tp-ec interval, and Tp-e/QT ratio.

CONCLUSION

Tp-e interval, Tp-ec interval, and Tp-e/QT ratio were greater in HIV-infected patients compared with healthy individuals. HIV-infected patients, particularly those with low baseline CD4 T-cell counts, should be closely monitored due to risk of SCD.

Relationship between SNP rs1764391 and Susceptibility, Risk Factors, Gene-environment Interactions of Acute Myocardial Infarction in Guangxi Han Chinese Population

BACKGROUND

Large-scale population studies showed that the SNP rs1764391 of Connexin37 gene also known as Cx37 gene may play a pivotal role in the occurrence and development of acute myocardial infarction (AMI). Published results, however, are highly controversial.

OBJECTIVE

This study aimed to examine the association between SNP rs1764391 of Cx37 and diseasesusceptibility, several risk factors, and gene-environment interactions of AMI in Guangxi Han Chinese population.

METHODS

In this study, 344 healthy controls and 344 AMI patients of Han Chinese population were enrolled. The TaqMan assay was implemented to identify genotypes of Cx37 and allele frequencies of SNP rs1764391 in both the AMI and control groups.

RESULTS

Significant differences were detected in TT genotype frequencies of SNP rs1764391 between the AMI and control groups (P < 0.05). In the context of gender stratification, the result was also statistically different in women (P < 0.05). Each variable such as age, BMI, diabetes, high blood pressure, smoking and TC was a risk factor and correlated significantly (P < 0.05) with the development of AMI. HDL-C correlated negatively with the risk of AMI (P < 0.001). BMI, smoking or alcohol consumed interacts significantly (P < 0.017) with the presence of the SNP rs1764391 CC genotype.

CONCLUSION

Evidences were presented that Cx37 rs1764391 variation may contribute to the risk for AMI, especially in women and this genetic variant may prove to be a potential biomarker for AMI risk stratification and may prove to be a useful target for therapeutic intervention to further improve prognosis in high-risk patients.

Arm-ECG Wireless Sensor System for Wearable Long-Term Surveillance of Heart Arrhythmias

This article presents the devising, development, prototyping and assessment of a wearable arm-ECG sensor system (WAMECG1) for long-term non-invasive heart rhythm monitoring, and functionalities for acquiring, storing, visualizing and transmitting high-quality far-field electrocardiographic signals. The system integrates the main building blocks present in a typical ECG monitoring device such as the skin surface electrodes, front-end amplifiers, analog and digital signal conditioning filters, flash memory and wireless communication capability. These are integrated into a comfortable, easy to wear, and ergonomically designed arm-band ECG sensor system which can acquire a bipolar ECG signal from the upper arm of the user over a period of 72 h. The small-amplitude bipolar arm-ECG signal is sensed by a reusable, long-lasting, Ag–AgCl based dry electrode pair, then digitized using a programmable sampling rate in the range of 125 to 500 Hz and transmitted via Wi-Fi. The prototype comparative performance assessment results showed a cross-correlation value of 99.7% and an error of less than 0.75% when compared to a reference high-resolution medical-grade ECG system. Also, the quality of the recorded far-field bipolar arm-ECG signal was validated in a pilot trial with volunteer subjects from within the research team, by wearing the prototype device while: (a) resting in a chair; and (b) doing minor physical activities. The R-peak detection average sensibilities were 99.66% and 94.64%, while the positive predictive values achieved 99.1% and 92.68%, respectively. Without using any additional algorithm for signal enhancement, the average signal-to-noise ratio (SNR) values were 21.71 and 18.25 for physical activity conditions (a) and (b) respectively. Therefore, the performance assessment results suggest that the wearable arm-band prototype device is a suitable, self-contained, unobtrusive platform for comfortable cardiac electrical activity and heart rhythm logging and monitoring.

Early whole-body CT for treatment guidance in patients with return of spontaneous circulation after cardiac arrest

PURPOSE

Non-traumatic cardiac arrest (CA) and return of spontaneous circulation (ROSC) after cardiopulmonary resuscitation (CPR) are often associated with multiple pathologies. Expecting a high prevalence of important findings, a whole-body CT (WBCT) could be of relevance for therapy. The aim of this study is to investigate the feasibility and diagnostic yield of an early WBCT in this setting.

METHODS

This single-center retrospective study included 100 consecutive patients (27 female; 73 male; mean age 68.5± 12.57 years) with non-traumatic, in- and out-of-hospital CA and ROSC following CPR, who underwent a contrast-enhanced WBCT within 6 h after ROSC over 12 months. CT findings were determined corresponding to anatomical region.

RESULTS

Early WBCT was successfully carried out in 100% of the patients with CA and ROSC after CPR. Acute pathologies were found not only in the chest but also in the head (15%) and the abdomen (6%). Early global brain edema (n = 12), acute stroke (n = 3), pulmonary embolism (n = 10), pneumothorax (26%), acute abdominal pathologies (n = 6), iatrogenic bleeding (4%), and CPR-related injuries (93%) were detected by CT right from the beginning of the post-cardiac arrest care.

CONCLUSIONS

An early WBCT is feasible and provides added diagnostic value for patients with ROSC after non-traumatic CA.

Extracorporeal cardiopulmonary resuscitation in out-of-hospital cardiac arrest: Ethical considerations

Out-of-hospital cardiac arrest (OHCA) continues to be a leading cause of mortality worldwide. In Canada over 40,000 cardiac arrests that occur each year, a majority occur unexpectedly outside of the hospital setting. However, the reality is that without rapid and appropriate treatment within minutes, most victims will die before reaching the hospital. In the late 1980s case reports identifying favorable outcomes with the use of extracorporeal cardiopulmonary resuscitation (eCPR) in out-of-hospital cardiac arrest (OHCA) began to be reported. Since then case reports, observational studies, propensity analysis, and a systematic review of international practices continues to suggest eCPR as a feasible intervention for refractory ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT) in select adult patients. However, in spite of this mounting base of evidence, clinicians continue to report concerns over a paucity of robust data showing definitive eCPR effectiveness compared with conventional resuscitation. This review will explore the ethical issues related to the impact eCPR might have on the orthodoxy pertaining to current resuscitation strategies, the impact of shifting decision-making on families particularly in dealing with a "bridge to nowhere" scenario, a call to accounting for greater data integrity and improved outcome reporting to assess eCPR effectiveness, and addressing the "Should we just do it" question. A recommendation is proposed for the creation of an ethics consultation service to assist families and staff in dealing with the invariable value conflicts and stresses likely to arise.

Mutational and phenotypic spectra of KCNE1 deficiency in Jervell and Lange-Nielsen Syndrome and Romano-Ward Syndrome

KCNE1 encodes a regulatory subunit of the KCNQ1 potassium channel-complex. Both KCNE1 and KCNQ1 are necessary for normal hearing and cardiac ventricular repolarization. Recessive variants in these genes are associated with Jervell and Lange-Nielson syndrome (JLNS1 and JLNS2), a cardio-auditory syndrome characterized by congenital profound sensorineural deafness and a prolonged QT interval that can cause ventricular arrhythmias and sudden cardiac death. Some normal-hearing carriers of heterozygous missense variants of KCNE1 and KCNQ1 have prolonged QT intervals, a dominantly inherited phenotype designated Romano-Ward syndrome (RWS), which is also associated with arrhythmias and elevated risk of sudden death. Coassembly of certain mutant KCNE1 monomers with wild-type KCNQ1 subunits results in RWS by a dominant negative mechanism. This paper reviews variants of KCNE1 and their associated phenotypes, including biallelic truncating null variants of KCNE1 that have not been previously reported. We describe three homozygous nonsense mutations of KCNE1 segregating in families ascertained ostensibly for nonsyndromic deafness: c.50G>A (p.Trp17*), c.51G>A (p.Trp17*), and c.138C>A (p.Tyr46*). Some individuals carrying missense variants of KCNE1 have RWS. However, heterozygotes for loss-of-function variants of KCNE1 may have normal QT intervals while biallelic null alleles are associated with JLNS2, indicating a complex genotype-phenotype spectrum for KCNE1 variants.

Beta-Blockers and ACE Inhibitors Are Associated with Improved Survival Secondary to Ventricular Tachyarrhythmia

OBJECTIVE

The study sought to assess the impact of treatment with beta-blocker (BB) or ACE inhibitor/angiotensin receptor blocker (ACEi/ARB) on secondary survival in patients presenting with ventricular tachyarrhythmia.

BACKGROUND

Data regarding outcome of patients presenting with ventricular tachyarrhythmia treated with BB and ACEi/ARB is limited.

METHODS

A large retrospective registry was used including consecutive patients presenting with ventricular tachycardia and fibrillation from 2002 to 2016 on admission. Applying propensity-score matching for harmonization, the impact of "BB" and "ACEi/ARB" was comparatively evaluated. The primary prognostic outcome was long-term all-cause death at 3 years.

RESULTS

A total of 972 matched patients were included. Both patients with BB (long-term mortality rate 18 versus 27%; log rank p = 0.041; HR = 0.661; 95% CI = 0.443-0.986; p = 0.043) and with ACEi/ARB (long-term mortality rate 13 versus 23%; log rank p = 0.004; HR = 0.544; 95% CI = 0.359-0.824; p = 0.004) revealed better secondary survival compared to patients without after presenting with ventricular tachyarrhythmia on admission. The prognostic benefit of BB was comparable to ACEi/ARB (long-term mortality rate 21 versus 26%; log rank p = 0.539).

CONCLUSION

BB and ACEi/ARB were associated with improved secondary survival in patients surviving ventricular tachyarrhythmia on admission.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT02982473.

Sudden cardiac death due to primary malignant pericardial mesothelioma: Brief report and literature review

Sudden cardiac death is an unexpected clinical condition that typically occurs due to a cardiac cause, generally within 1 h of symptom onset, in people with known or unknown cardiac disease. Primary malignant pericardial mesothelioma, as a cause of sudden death, is an uncommon consequence of a rare disease. Herein, we present a case of cardiac tamponade due to a primary pericardial mesothelioma. Cytological, histopathology and gross post-mortem findings, in a previously asymptomatic 46-old-year man, are reported. The medical literature regarding this topic is also reviewed.

Pathophysiology, incidence, management, and consequences of cardiac arrhythmia in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension

Arrhythmias are increasingly recognized as serious, end-stage complications of pre-capillary pulmonary hypertension, including pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). Although arrhythmias contribute to symptoms, morbidity, in-hospital mortality, and possibly sudden death in PAH/CTEPH, there remains a paucity of epidemiologic, pathophysiologic, and outcome data to guide management of these patients. This review summarizes the most current evidence on the topic: from the molecular mechanisms driving arrhythmia in the hypertrophied or failing right heart, to the clinical aspects of epidemiology, diagnosis, and management.

Coronary Artery Abnormalities as the Cause of Sudden Cardiac Death: A 20-Year Review

In this case series, we delve into the database of medicolegal cases of the Forensic Pathology Department at Hamilton Health Sciences in Hamilton Ontario from the last 20 years (1996-2017), and review cases of sudden cardiac death due to coronary artery abnormalities. We found 17 cases that fit the criteria, which gave us an incidence of 1.34 per 1000 cases. These cases were further audited for age, sex, type of coronary artery abnormality, symptoms before demise, circumstances of death, presence of significant atherosclerotic disease, and toxicology. Two more recent cases underwent postmortem genetic testing, and we reported on the result of one of these molecular studies. In our case series, the most commonly affected coronary artery was the right coronary artery, with the most common anomaly being abnormal origin from the left sinus of Valsalva. Although the literature maintains that left coronary artery from the opposite sinus is associated with higher incidence of SCD, our study shows that RCAs from the opposite aortic sinus, including those deemed to be low risk by classification, can be causes of SCD.

High-Fat-Diet-Induced Obesity Produces Spontaneous Ventricular Arrhythmias and Increases the Activity of Ryanodine Receptors in Mice

Ventricular arrhythmias are a common cause of sudden cardiac death, and their occurrence is higher in obese subjects. Abnormal gating of ryanodine receptors (RyR2), the calcium release channels of the sarcoplasmic reticulum, can produce ventricular arrhythmias. Since obesity promotes oxidative stress and RyR2 are redox-sensitive channels, we investigated whether the RyR2 activity was altered in obese mice. Mice fed a high fat diet (HFD) became obese after eight weeks and exhibited a significant increase in the occurrence of ventricular arrhythmias. Single RyR2 channels isolated from the hearts of obese mice were more active in planar bilayers than those isolated from the hearts of the control mice. At the molecular level, RyR2 channels from HFD-fed mice had substantially fewer free thiol residues, suggesting that redox modifications were responsible for the higher activity. Apocynin, provided in the drinking water, completely prevented the appearance of ventricular arrhythmias in HFD-fed mice, and normalized the activity and content of the free thiol residues of the protein. HFD increased the expression of NOX4, an isoform of NADPH oxidase, in the heart. Our results suggest that HFD increases the activity of RyR2 channels via a redox-dependent mechanism, favoring the appearance of ventricular arrhythmias.