The spectrum of epidemiology underlying sudden cardiac death

The effect of age, gender, economic state, and urbanization on the temporal trend in sudden cardiac arrest: a nationwide population-based cohort study

Background

Sudden cardiac arrest (SCA) has not been well studied in Asian countries. This study investigated the temporal trends in the incidence and outcomes of SCA and the impact of age, gender, economic state, and urbanization on SCA using a nationwide population-based sample cohort of South Korea.

Methods

In the Korean National Health Insurance Service—Sample Cohort consisting of one million persons from 2003 through 2013, we identified 5,675 (0.56%) patients with SCA using ICD-10 code I46 and I49.0. We evaluated the impact of the age, gender, household income, and urbanization level on the incidence and outcome of SCA.

Results

During the study period, the overall age- and gender-adjusted annual incidence of SCA increased by 46.9% from 30.9 in 2003 to 45.4 in 2013 (per 100,000 person-years, p < 0.001 for trend). The medical cost per 100,000 person-years also greatly increased about four times (p < 0.001 for trend). The overall adjusted survival to hospital discharge rate increased from 8.9% in 2003 to 13.2% in 2013 (adjusted rate ratio per year 1.05; p < 0.001 for trend). Old age and low household incomes of the population was related to increased SCA and poor survival to hospital discharge rate. The proportion of patients with intensive or advanced therapeutic modalities after SCA greatly increased from 1.6% in 2003 to 10.0% in 2013 (p < 0.001 for trend). This increase was consistent regardless of age, gender, economic state, and urbanization level.

Conclusions

Although the incidence of SCA was increased, the outcome was improved for the decade. However, in the elderly and low-income population, the incidence of SCA continued to rise and survival outcome was not improved.

Harmonization of the definition of sudden cardiac death in longitudinal cohorts of the European Sudden Cardiac Arrest network - towards Prevention, Education, and New Effective Treatments (ESCAPE-NET) consortium

BACKGROUND

The burden of sudden cardiac death (SCD) in the general population is substantial and SCD frequently occurs among people with few or no known risk factors for cardiac disease. Reported incidences of SCD vary due to differences in definitions and methodology between cohorts. This study aimed to develop a method for adjudicating SCD cases in research settings and to describe uniform case definitions of SCD in an international consortium harmonizing multiple longitudinal study cohorts.

METHODS

The harmonized SCD definitions include both case definitions using data from multiple sources (eg, autopsy reports, medical history, eyewitnesses) as well as a method using only information from registers (eg, cause of death registers, ICD-10 codes). Validation of the register-based method was done within the consortium using the multiple sources definition as gold standard and presenting sensitivity, specificity, accuracy and positive predictive value.

RESULTS

Consensus definitions of "definite," "possible" and "probable" SCD for longitudinal study cohorts were reached. The definitions are based on a stratified approach to reflect the level of certainty of diagnosis and degree of information. The definitions can be applied to both multisource and register-based methods. Validation of the method using register-information in a cohort comprising 1335 cases yielded a sensitivity of 74%, specificity of 88%, accuracy of 86%, and positive predictive value of 54%.

CONCLUSIONS

This study demonstrated that a harmonization of SCD classification across different methodological approaches is feasible. The developed classification can be used to study SCD in longitudinal cohorts and to merge cohorts with different levels of information.

N-Terminal Pro-B-Type Natriuretic Peptide in Risk Stratification of Heart Failure Patients With Implantable Cardioverter-Defibrillator

Background

The prognostic value of N-terminal pro-B-type natriuretic peptide (NT-proBNP) in heart failure (HF) is well-established. However, whether it could facilitate the risk stratification of HF patients with implantable cardioverter-defibrillator (ICD) is still unclear.

Objective

To determine the associations between baseline NT-proBNP and outcomes of all-cause mortality and first appropriate shock due to sustained ventricular tachycardia/ventricular fibrillation (VT/VF) in ICD recipients.

Methods and results

N-terminal pro-B-type natriuretic peptide was measured before ICD implant in 500 patients (mean age 60.2 ± 12.0 years; 415 (83.0%) men; 231 (46.2%) Non-ischemic dilated cardiomyopathy (DCM); 136 (27.2%) primary prevention). The median NT-proBNP was 854.3 pg/ml (interquartile range [IQR]: 402.0 to 1,817.8 pg/ml). We categorized NT-proBNP levels into quartiles and used a restricted cubic spline to evaluate its nonlinear association with outcomes. The incidence rates of mortality and first appropriate shock were 5.6 and 9.1%, respectively. After adjusting for confounding factors, multivariable Cox regression showed a rise in NT-proBNP was associated with an increased risk of all-cause mortality. Compared with the lowest quartile, the hazard ratios (HRs) with 95% CI across increasing quartiles were 1.77 (0.71, 4.43), 3.98 (1.71, 9.25), and 5.90 (2.43, 14.30) for NT-proBNP (p for trend &lt; 0.001). A restricted cubic spline demonstrated a similar pattern with an inflection point found at 3,231.4 pg/ml, beyond which the increase in NT-proBNP was not associated with increased mortality (p for nonlinearity &lt; 0.001). Fine-Gray regression was used to evaluate the association between NT-proBNP and first appropriate shock accounting for the competing risk of death. In the unadjusted, partial, and fully adjusted analysis, however, no significant association could be found regardless of NT-proBNP as a categorical variable or log-transformed continuous variable (all p &gt; 0.05). No nonlinearity was found, either (p = 0.666). Interactions between NT-proBNP and predefined factors were not found (all p &gt; 0.1).

Conclusion

In HF patients with ICD, the rise in NT-proBNP is independently associated with increased mortality until it reaches the inflection point. However, its association with the first appropriate shock was not found. Patients with higher NT-proBNP levels might derive less benefit from ICD implant.

Knowledge, Attitude and Decision-making of Nurses in the Resuscitation Team towards Terminating Resuscitation and Do-not-Resuscitate Order

Background

Making appropriate decisions for cardiopulmonary resuscitation (CPR) is very challenging for healthcare providers. This study aimed to evaluate knowledge, attitude, and decision making about do-not-resuscitate (DNR) and termination of resuscitation (ToR) among nurses in the resuscitation team.

Methods

This descriptive cross-sectional study was conducted in April-September 2020. Participants were 128 nurses from the CPR teams of two hospitals in Kermanshah and Hamedan, Iran. A valid and reliable researcher-made instrument was used for data collection. Data were analyzed using the Chi-square, Fisher's exact, and Mann-Whitney U tests, the Spearman's correlation analysis, and the logistic and rank regression analyses.

Results

Only 22.7% and 37.5% of participants had adequate knowledge about ToR and DNR. The significant predictor of DNR and ToR knowledge was educational level and the significant predictors of decision making for CPR were educational level, gender, and history of receiving CPR-related education (P<0.05). When facing a cardiac arrest and indication of DNR or ToR, 12.5% of participants reported that they would not start CPR, 21.5% of them reported that they would terminate CPR, and 14.8% of them reported that they would perform slow code. The DNR decision had significant relationship with educational level, DNR knowledge, and ToR knowledge (P< 0.05), while the ToR decision had significant relationship with educational level and ToR knowledge (P<0.05).

Conclusion

Nurses' limited DNR and ToR knowledge and physicians' conflicting orders and documentation can cause ethical challenges for nurses. Clear guidelines for DNR orders or TOR is necessary for nurses, in order to prevent any potential confusion, legal or psychosocial issues and concerns surrounding CPR and improve their involvement in CPR decision making process.

Arrhythmias in Female Patients: Incidence, Presentation and Management

There is a growing appreciation for differences in epidemiology, treatment, and outcomes of cardiovascular conditions by sex. Historically, cardiovascular clinical trials have under-represented females, but findings have nonetheless been applied to clinical care in a sex-agnostic manner. Thus, much of the collective knowledge about sex-specific cardiovascular outcomes result from post hoc and secondary analyses. In some cases, these investigations have revealed important sex-based differences with implications for optimizing care for female patients with arrhythmias. This review explores the available evidence related to cardiac arrhythmia care among females, with emphasis on areas in which important sex differences are known or suggested. Considerations related to improving female enrollment in clinical trials as a way to establish more robust clinical evidence for the treatment of females are discussed. Areas of remaining evidence gaps are provided, and recommendations for areas of future research and specific action items are suggested. The overarching goal is to improve appreciation for sex-based differences in cardiac arrhythmia care as 1 component of a comprehensive plan to optimize arrhythmia care for all patients.

Altered Expression of Zonula occludens-1 Affects Cardiac Na+ Channels and Increases Susceptibility to Ventricular Arrhythmias

Zonula occludens-1 (ZO-1) is an intracellular scaffolding protein that orchestrates the anchoring of membrane proteins to the cytoskeleton in epithelial and specialized tissue including the heart. There is clear evidence to support the central role of intracellular auxiliary proteins in arrhythmogenesis and previous studies have found altered ZO-1 expression associated with atrioventricular conduction abnormalities. Here, using human cardiac tissues, we identified all three isoforms of ZO-1, canonical (Transcript Variant 1, TV1), CRA_e (Transcript Variant 4, TV4), and an additionally expressed (Transcript Variant 3, TV3) in non-failing myocardium. To investigate the role of ZO-1 on ventricular arrhythmogenesis, we generated a haploinsufficient ZO-1 mouse model (ZO-1^+/-). ZO-1^+/- mice exhibited dysregulated connexin-43 protein expression and localization at the intercalated disc. While ZO-1^+/- mice did not display abnormal cardiac function at baseline, adrenergic challenge resulted in rhythm abnormalities, including premature ventricular contractions and bigeminy. At baseline, ventricular myocytes from the ZO-1^+/- mice displayed prolonged action potential duration and spontaneous depolarizations, with ZO-1^+/- cells displaying frequent unsolicited (non-paced) diastolic depolarizations leading to spontaneous activity with multiple early afterdepolarizations (EADs). Mechanistically, ZO-1 deficient myocytes displayed a reduction in sodium current density (I_Na) and an increased sensitivity to isoproterenol stimulation. Further, ZO-1 deficient myocytes displayed remodeling in I_Ca current, likely a compensatory change. Taken together, our data suggest that ZO-1 deficiency results in myocardial substrate susceptible to triggered arrhythmias.

Proteomics-Based Serum Alterations of the Human Protein Expression after Out-of-Hospital Cardiac Arrest: Pilot Study for Prognostication of Survivors vs. Non-Survivors at Day 1 after Return of Spontaneous Circulation (ROSC)

Background: Targeted temperature management (TTM) is considered standard therapy for patients after out-of-hospital cardiac arrest (OHCA), cardiopulmonary resuscitation (CPR), and return of spontaneous circulation (ROSC). To date, valid protein markers do not exist to prognosticate survivors and non-survivors before the end of TTM. The aim of this study is to identify specific protein patterns/arrays, which are useful for prediction in the very early phase after ROSC. Material and Methods: A total of 20 adult patients with ROSC (19 male, 1 female; 69.9 ± 9.5 years) were included and dichotomized in two groups (survivors and non-survivors at day 30). Serum samples were drawn at day 1 after ROSC (during TTM). Three panels (organ failure, metabolic, neurology, inflammation; OLINK, Uppsala, Sweden) were utilised. A total of four proteins were found to be differentially regulated (>2- or <−0.5-fold decrease; t-test). Bioinformatic platforms were utilised to analyse pathways and identify signalling cascades and to screen for potential biomarkers. Results: A total of 276 proteins were analysed and revealed only 11 statistically significant protein alterations (Siglec-9, LAYN, SKR3, JAM-B, N2DL-2, TNF-B, BAMBI, NUCB2, STX8, PTK7, and PVLAB). Following the Bonferroni correction, no proteins were found to be regulated as statistically significant. Concerning the protein fold change for clinical significance, four proteins (IL-1 alpha, N-CDase, IL5, CRH) were found to be regulated in a clinically relevant context. Conclusions: Early analysis at 1 day after ROSC was not sufficiently possible during TTM to prognosticate survival or non-survival after OHCA. Future studies should evaluate protein expression later in the course after ROSC to identify promising protein candidates.

Kynurenine Pathway Metabolites as Potential Clinical Biomarkers in Coronary Artery Disease

Coronary artery disease (CAD) is one of the leading cause of mortality worldwide. Several risk factors including unhealthy lifestyle, genetic background, obesity, diabetes, hypercholesterolemia, hypertension, smoking, age, etc. contribute to the development of coronary atherosclerosis and subsequent coronary artery disease. Inflammation plays an important role in coronary artery disease development and progression. Pro-inflammatory signals promote the degradation of tryptophan via the kynurenine pathway resulting in the formation of several immunomodulatory metabolites. An unbalanced kynurenic pathway has been implicated in the pathomechanisms of various diseases including CAD. Significant improvements in detection methods in the last decades may allow simultaneous measurement of multiple metabolites of the kynurenine pathway and such a thorough analysis of the kynurenine pathway may be a valuable tool for risk stratification and determination of CAD prognosis. Nevertheless, imbalance in the activities of different branches of the kynurenine pathway may require careful interpretation. In this review, we aim to summarize clinical evidence supporting a possible use of kynurenine pathway metabolites as clinical biomarkers in various manifestations of CAD.

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.

The Differences of CPR Duration Between Shockable and Non-shockable Rhythms in Predicting The Benefit of Target Temperature Management

BACKGROUND

Among cardiac arrest (CA) survivors, whether the combination of duration of cardiopulmonary resuscitation (CPR) and shockable/nonshockable rhythms during resuscitation can help predict the benefit of targeted temperature management (TTM) remains un-investigated.

MATERIALS AND METHODS

This multicenter retrospective cohort study enrolled 479 nontraumatic adult CA survivors with TTM and CPR duration <60 min during January 2014 to June 2019 from the TaIwan network of targeted temperature ManagEment for CARDiac arrest (TIMECARD) registry. The differences of CPR duration between shockable and nonshockable rhythms in predicting outcomes in the studied population was evaluated.

RESULTS

We observed that 205 patients (42.8%) survived to hospital discharge and 100 patients (20.9%) presented favorable neurological outcomes at discharge. The enrolled patients were further re-classified into four groups according to shockable/nonshockable rhythms and CPR duration. Patients with shockable rhythms and shorter CPR duration had better survival-to-discharge (adjusted odds ratio [OR] = 2.729, 95% confidence interval [CI] = 1.384-5.383, P = 0.004) and neurological recovery (adjusted OR = 9.029, 95%CI = 3.263-24.983, P < 0.001) than did those with nonshockable rhythms and longer CPR duration.

CONCLUSION

The CPR duration for predicting outcomes differs between CA patients with shockable and nonshockable rhythms. The combination of shockable/nonshockable rhythms and CPR duration may help predict the prognosis in CA survivors undergoing TTM.

Clinical Genetics of Inherited Arrhythmogenic Disease in the Pediatric Population

Sudden death is a rare event in the pediatric population but with a social shock due to its presentation as the first symptom in previously healthy children. Comprehensive autopsy in pediatric cases identify an inconclusive cause in 40-50% of cases. In such cases, a diagnosis of sudden arrhythmic death syndrome is suggested as the main potential cause of death. Molecular autopsy identifies nearly 30% of cases under 16 years of age carrying a pathogenic/potentially pathogenic alteration in genes associated with any inherited arrhythmogenic disease. In the last few years, despite the increasing rate of post-mortem genetic diagnosis, many families still remain without a conclusive genetic cause of the unexpected death. Current challenges in genetic diagnosis are the establishment of a correct genotype-phenotype association between genes and inherited arrhythmogenic disease, as well as the classification of variants of uncertain significance. In this review, we provide an update on the state of the art in the genetic diagnosis of inherited arrhythmogenic disease in the pediatric population. We focus on emerging publications on gene curation for genotype-phenotype associations, cases of genetic overlap and advances in the classification of variants of uncertain significance. Our goal is to facilitate the translation of genetic diagnosis to the clinical area, helping risk stratification, treatment and the genetic counselling of families.

OUP accepted manuscript

Aims

Genetic testing is recommended in specific inherited heart diseases but its role remains unclear and it is not currently recommended in unexplained cardiac arrest (UCA). We sought to assess the yield and clinical utility of genetic testing in UCA using whole-exome sequencing (WES).

Methods and results

Survivors of UCA requiring external defibrillation were included from the Cardiac Arrest Survivor with Preserved Ejection fraction Registry. Whole-exome sequencing was performed, followed by assessment of rare variants in previously reported cardiovascular disease genes. A total of 228 UCA survivors (mean age at arrest 39 ± 13 years) were included. The majority were males (66%) and of European ancestry (81%). Following advanced clinical testing at baseline, the likely aetiology of cardiac arrest was determined in 21/228 (9%) cases. Whole-exome sequencing identified a pathogenic or likely pathogenic (P/LP) variant in 23/228 (10%) of UCA survivors overall, increasing the proportion of ‘explained’ cases from 9% only following phenotyping to 18% when combining phenotyping with WES. Notably, 13 (57%) of the 23 P/LP variants identified were located in genes associated with cardiomyopathy, in the absence of a diagnosis of cardiomyopathy at the time of arrest.

Conclusions

Genetic testing identifies a disease-causing variant in 10% of apparent UCA survivors. The majority of disease-causing variants was located in cardiomyopathy-associated genes, highlighting the arrhythmogenic potential of such variants in the absence of an overt cardiomyopathy diagnosis. The present study supports the use of genetic testing including assessment of arrhythmia and cardiomyopathy genes in survivors of UCA.

The Outcome of Long QT Syndrome, a Korean Single Center Study

Congenital long QT syndrome is an inherited cardiac channelopathy, causing fatal arrhythmia. In this study, we conducted a retrospective cohort study on 105 congenital LQTS patients and its outcome in a tertiary center. The 10-year event free survival rate was 73.2%, and the outcome was different according to the genotypes. With treatment, all survived except one. The genetic analysis and risk stratification may be essential for better outcome and further nationwide and large scaled studies are required.

Background and Objectives

Although long QT syndrome (LQTS) is a potentially life-threatening inherited cardiac channelopathy, studies documenting the long-term clinical data of Korean patients with LQTS are scarce.

Methods

This retrospective cohort study included 105 patients with LQTS (48 women; 45.7%) from a single tertiary center. The clinical outcomes were analyzed for the rate of freedom from breakthrough cardiac events (BCEs), additional treatment needed, and death.

Results

LQTS was diagnosed at a median age of 11 (range, 0.003–80) years. Genetic testing was performed on 90 patients (yield, 71.1%). The proportions of genetically confirmed patients with LQTS types 1, 2, 3, and others were 34.4%, 12.2%, 12.2%, and 12.2%, respectively. In the symptomatic group (n=70), aborted cardiac arrest was observed in 30% of the patients. Treatments included medications in 60 patients (85.7%), implantable cardioverter-defibrillators in 27 (38.6%; median age, 17 years; range, 2–79 years), and left cardiac sympathetic denervation surgery in 7 (10%; median age, 13 years; range, 2–34). The 10-year BCE-free survival rate was 73.2%. By genotype, significant differences were observed in BCEs despite medication (p<0.001). The 10-year BCE-free survival rate was the highest in patients with LQTS type 1 (81.8%) and the lowest in those with multiple LQTS-associated mutations (LQTM). All patients with LQTS survived, except for one patient who had LQTM.

Conclusions

Good long-term outcomes can be achieved by using recently developed genetically tailored management strategies for patients with LQTS.

Association between nationwide introduction of public-access defibrillation and sudden cardiac death in Japan: An interrupted time-series analysis

BACKGROUND

The effectiveness of public-use of automated external defibrillators in reducing the number of sudden cardiac death (SCD) cases at the national level is largely unknown. Our study aimed to evaluate whether the nationwide introduction of public-access-defibrillation (PAD) in 2004 affected the trend of annual sudden cardiac death (SCD) rates in Japan.

METHODS

The number of nationwide SCDs occurring in people aged five years and older was extracted from Japanese demographic statistics (1995-2015). Segmented regression analysis was performed on the interrupted time series data stratified by age and sex to evaluate changes in trends of rates of annual SCDs after the PAD introduction in Japan.

RESULTS

After the PAD introduction in 2004, we observed a significant decrease in trends of annual SCD rates for those aged 5-19 years (the ratio of trends between pre and post PAD introduction (RT) = 0.886, 95%CI: 0.801 to 0.980), 20-34 years (RT = 0.932; 95%CI: 0.906, 0.958), 35-49 years (RT = 0.953; 95%CI: 0.929, 0.977) and 50-64 years (RT = 0.971; 95%CI: 0.971, 0.991). However, the decrease was not observed for those aged 65 years and older. In the age and sex stratified analysis, there was a significant decrease in RT among males aged 5-64 years, and among females 35-49 years.

CONCLUSION

The nationwide trend of annual rate of SCDs between 5 and 64 years old significantly decreased after the introduction of PAD in 2004 in Japan. Further, the reduction was more evident in males.

The Purkinje network plays a major role in low-energy ventricular defibrillation

BACKGROUND

During ventricular fibrillation (VF), targeting the excitable gap (EG) of reentry throughout the myocardium with low-energy surface stimulation shows promise for painless defibrillation. However, the Purkinje network may provide alternative pathways for reentry to evade termination. This study investigates the role of the Purkinje network in painless defibrillation.

METHODS

In a computational human biventricular model featuring a Purkinje network, VF was initiated with 4 Hz epicardial pacing. Defibrillation was attempted by stimulating myocardial surface EG with a low-energy 2 ms duration pulse at 2x stimulus capture, which was administered at coupling intervals incremented by 0.25 s between 0.25 and 5 s after VF initiation. Defibrillation was accomplished if reentry ceased ≤ 1 s after the defibrillation pulse. The protocol was repeated with the Purkinje network and myocardial surface EG stimulated simultaneously, and again after uncoupling the Purkinje network from the myocardium.

RESULTS

VF with the Purkinje network coupled and uncoupled had comparable dominant frequency in the left (3.81 ± 0.44 versus 3.77 ± 0.53 Hz) and right (3.80 ± 0.37 versus 3.76 ± 0.48 Hz) ventricles. When uncoupling the Purkinje network, myocardial surface EG stimulation terminated VF for all defibrillation pulses. When coupled, myocardial EG surface stimulation terminated VF for only 55% of the defibrillation pulses, but improved to 100% when stimulated simultaneously with Purkinje network EG. Defibrillation failures were attributed to EG evading stimulation in the Purkinje network.

CONCLUSIONS

Defibrillation that exclusively targets myocardium can fail due to accessory pathways in the Purkinje network that allow for reentrant activity to evade termination and maintain VF. Painless defibrillation strategies should be adapted to include the Purkinje network.

The short-chain fatty acid propionate improved ventricular electrical remodeling in a rat model with myocardial infarction

The short-chain fatty acid (SCFA) propionate (C3), a microorganism metabolite produced by gut microbial fermentation, has parasympathetic-activation effects. The cardiac autonomic rebalancing strategy is considered as an important therapeutic approach to myocardial infarction (MI)-produced ventricular arrhythmias (VAs). Thus, our research was designed to clarify the potential functions of the SCFA propionate in VAs and cardiac electrophysiology in MI rats. A hundred adult Sprague-Dawley rats were allocated to four groups: the sham group (200 mM sodium chloride), the sham + C3 group (200 mM propionate), the MI group (200 mM sodium chloride) and the MI + C3 group (200 mM propionate). In comparison with the sham group, propionate significantly increased the parasympathetic components heart rate variability (HRV) and acetylcholine levels, prolonged cardiac repolarization, induced STAT3 phosphorylation and up-regulated the c-fos expression in nodose ganglia and solitary nucleus. Propionate intake reduced the susceptibility to VAs. MI induced by coronary ligation caused a significant increase in the sympathetic components HRV, abnormal repolarization, global repolarization dispersion, norepinephrine and inflammatory cytokines, reduction and redistribution of Connexin 43 in the infarcted border zone, and activation of NFκB, which were attenuated in the MI + C3 group. Oral propionate supplementation, as a nutritional intervention, protected the heart against MI-induced VAs and cardiac electrophysiology instability partly by parasympathetic activation based on the gut-brain axis.

Cardiac arrest in special circumstances

PURPOSE OF REVIEW

European Resuscitation Council Guidelines for Cardiopulmonary Resuscitation prioritize treatments like chest compression and defibrillation, known to be highly effective for cardiac arrest from cardiac origin. This review highlights the need to modify this approach in special circumstances.

RECENT FINDINGS

Potentially reversible causes of cardiac arrest are clustered into four Hs and four Ts (Hypoxia, Hypovolaemia, Hyperkalaemia/other electrolyte disorders, Hypothermia, Thrombosis, Tamponade, Tension pneumothorax, Toxic agents). Point-of-care ultrasound has its role in identification of the cause and targeting treatment. Time-critical interventions may even prevent cardiac arrest if applied early. The extracorporeal CPR (eCPR) or mechanical CPR should be considered for bridging the period needed to reverse the precipitating cause(s). There is low quality of evidence available to guide the treatment in the majority of situations. Some topics (pulmonary embolism, eCPR, drowning, pregnancy and opioid toxicity) were included in recent ILCOR reviews and evidence updates but majority of recommendations is based on individual systematic reviews, scoping reviews, evidence updates and expert consensus.

SUMMARY

Cardiac arrests from reversible causes happen with lower incidence. Return of spontaneous circulation and neurologically intact survival can hardly be achieved without a modified approach focusing on immediate treatment of the underlying cause(s) of cardiac arrest.

Epidemiology and risk factors of sudden cardiac arrest

PURPOSE OF REVIEW

Sudden cardiac arrest (SCA) remains a major health burden around the globe, most often occurring in the community (out-of-hospital cardiac arrest [OHCA]). SCA accounts for 15-20% of all natural deaths in adults in the USA and Western Europe, and up to 50% of all cardiovascular deaths. To reduce this burden, more knowledge is needed about its key facets such as its incidence in various geographies, its risk factors, and the populations that may be at risk.

RECENT FINDINGS

SCA results from a complex interaction of inherited and acquired causes, specific to each individual. Resolving this complexity, and designing personalized prevention and treatment, requires an integrated approach in which big datasets that contain all relevant factors are collected, and a multimodal analysis. Such datasets derive from multiple data sources, including all players in the chain-of-care for OHCA. This recognition has led to recently started large-scale collaborative efforts in Europe.

SUMMARY

Our insights into the causes of SCA are steadily increasing thanks to the creation of big datasets dedicated to SCA research. These insights may be used to earlier recognize of individuals at risk, the design of personalized methods for prevention, and more effective resuscitation strategies for OHCA.

Diabetes and Risk of Sudden Death in Coronary Artery Disease Patients Without Severe Systolic Dysfunction

OBJECTIVES

This study sought to determine the absolute and relative associations of diabetes mellitus (DM) and hemoglobin A1c (HbA1c) with sudden and/or arrhythmic death (SAD) versus other modes of death in patients with coronary artery disease (CAD) who do not qualify for implantable cardioverter-defibrillators.

BACKGROUND

Patients with CAD and DM are at elevated risk for SAD; however, it is unclear whether these patients would benefit from implantable cardioverter-defibrillators given competing causes of death and/or whether HbA1c might augment SAD risk stratification.

METHODS

In the PRE-DETERMINE study of 5,764 patients with CAD with left ventricular ejection fraction (LVEF) of >30% to 35%, competing risk analyses were used to compare the absolute and relative risks of SAD versus non-SAD by DM status and HbA1c level and to identify risk factors for SAD among 1,782 patients with DM.

RESULTS

Over a median follow-up of 6.8 years, DM and HbA1c were significantly associated with SAD and non-SAD (P < 0.05 for all comparisons); however, the cumulative incidence of non-SAD (19.2%; 95% CI: 17.3%-21.2%) was almost 4 times higher than SAD (4.8%; 95% CI: 3.8%-5.9%) in DM patients. A similar pattern of absolute risk was observed across categories of HbA1c. In analyses limited to patients with DM, HbA1c was not associated with SAD, whereas low LVEF, atrial fibrillation, and electrocardiogram measurements were associated with higher SAD risk.

CONCLUSIONS

In patients with CAD and LVEF of >30% to 35%, patients with DM and/or elevated HbA1c are at much higher absolute risk of dying from non-SAD than SAD. Clinical risk markers, and not HbA1c, were associated with SAD risk in patients with DM. (PRE-DETERMINE: Biologic Markers and MRI SCD Cohort Study; NCT01114269).

A Review of the Commercially Available ECG Detection and Transmission Systems-The Fuzzy Logic Approach in the Prevention of Sudden Cardiac Arrest

Sudden cardiac death (SCD) constitutes a major clinical and public health problem, whose death burden is comparable to the current worldwide pandemic. This comprehensive review encompasses the following topics: available rescue systems, wearable electrocardiograms (ECG), detection and transmission technology, and a newly developed fuzzy logic algorithm (FA) for heart rhythm classification which is state-of-the art in the field of SCD prevention. Project "PROTECTOR", the Polish Rapid Transtelephonic ECG to Obtain Resuscitation for development of a rapid rescue system for patients at risk of sudden cardiac arrest (SCA), is presented. If a lethal arrhythmia is detected on the basis of FA, the system produces an alarm signal audible for bystanders and transmits the alarm message along with location to the emergency medical center. Phone guided resuscitation can be started immediately because an automated external defibrillator (AED) localization map is available. An automatic, very fast diagnosis is a unique feature of the PROTECTOR prototype. The rapid detection of SCA is based on a processor characterized by 100% sensitivity and 97.8% specificity (as measured in the pilot studies). An integrated circuit which implements FA has already been designed and a diagnosis is made within few seconds, which is extremely important in ischemic brain damage prophylaxis. This circuit could be implemented in smart implants (Sis).

Stress, the autonomic nervous system, and sudden death

The existence of an important relationship between stress, the autonomic nervous system, and sudden cardiac death (SCD) has been long recognized. In the present essay we review the large number of conditions, acting at individual or at population level, that have been causally associated to SCD and discuss the mechanistic and translational value of the studies exploring such associations. These conditions include external stressors (earthquakes, wars) and internal stressors (anger, fear, loss of a loved one) and emotions of even opposite sign. Most situations confirm the time-honored view that increases in sympathetic activity are proarrhythmic whereas increases in vagal activity are protective; however, we will also show and discuss a condition in which the culprit appears to be the excess of vagal activity. The physiologic rationale underlying the most typical situations is on one hand the profibrillatory effect of the increase in the heterogeneity of repolarization secondary to the release of norepinephrine, and on the other the combined effect of acetylcholine to lower heart rate and to antagonize the cardiac effects of norepinephrine at ventricular level. An interesting facet of this potentially lethal relationship is that the elements involved are by no means always exceptional, and they can actually represent part of our everyday life.

Organized Structure of Ventricular Fibrillation during Prolonged Heart Perfusion in Dogs

The aim of the study was to identify the organized ventricular fibrillation (VF) activity in the dog heart and characterize its quantitative parameters during prolonged heart perfusion.

Forensic significance of intracardiac heme oxygenase-1 expression in acute myocardial ischemia

Heme oxygenase-1 (HO-1), an inducible stress-response protein, exerts anti-oxidant and anti-apoptotic effects. However, its significance in forensic diagnosis of acute ischemic heart diseases (AIHD) such as myocardial infarction (MI) is still unknown. We examined the immunohistochemical expression of HO-1 in the heart samples to discuss their forensic significance to determine acute cardiac ischemia. The heart samples were obtained from 23 AIHD cases and 33 non-AIHD cases as controls. HO-1 positive signals in cardiomyocyte nuclear were detected in 78.2% of AIHD cases, however, that were detected in only 24.2% control cases with statistical difference between AIHD and non-AIHD groups. In contrast to HO-1 protein expression, there was no significant difference in the appearance of myoglobin pallor regions and leukocyte infiltration in the hearts between AIHD and non-AIHD groups. From the viewpoints of forensic pathology, intracardiac HO-1 expression would be considered a valuable marker to diagnose AIHD as the cause of death.

Understanding Circadian Mechanisms of Sudden Cardiac Death: A Report From the National Heart, Lung, and Blood Institute Workshop, Part 1: Basic and Translational Aspects

Sudden cardiac death (SCD), the unexpected death due to acquired or genetic cardiovascular disease, follows distinct 24-hour patterns in occurrence. These 24-hour patterns likely reflect daily changes in arrhythmogenic triggers and the myocardial substrate caused by day/night rhythms in behavior, the environment, and endogenous circadian mechanisms. To better address fundamental questions regarding the circadian mechanisms, the National Heart, Lung, and Blood Institute convened a workshop, Understanding Circadian Mechanisms of Sudden Cardiac Death. We present a 2-part report of findings from this workshop. Part 1 summarizes the workshop and serves to identify research gaps and opportunities in the areas of basic and translational research. Among the gaps was the lack of standardization in animal studies for reporting environmental conditions (eg, timing of experiments relative to the light dark cycle or animal housing temperatures) that can impair rigor and reproducibility. Workshop participants also pointed to uncertainty regarding the importance of maintaining normal circadian rhythmic synchrony and the potential pathological impact of desynchrony on SCD risk. One related question raised was whether circadian mechanisms can be targeted to reduce SCD risk. Finally, the experts underscored the need for studies aimed at determining the physiological importance of circadian clocks in the many different cell types important to normal heart function and SCD. Addressing these gaps could lead to new therapeutic approaches/molecular targets that can mitigate the risk of SCD not only at certain times but over the entire 24-hour period.

Reduced Serum Zinc Ion Concentration Is Associated with Coronary Heart Disease

Imbalances in trace element concentrations in the blood as a result of poor nutrition may affect the development of coronary heart disease. To study the relationship between zinc ion concentration in the peripheral blood and coronary heart disease, we performed multiple logistic regression and hierarchical analyses on blood measurements of 3541 patients. The experimental group comprised 1253 patients diagnosed with coronary heart disease, and the control group included 2288 healthy patients. The zinc ion concentrations were measured by a color rendering method, and the results were analyzed using SPSS software. Fifteen laboratory quality evaluation samples from the Clinical Laboratory Center of the Chinese Ministry of Health were selected for analysis. The mean values and average bias were calculated. The estimated qualified judgment standard was < 1/2 TEa (the allowable total error for zinc). A hierarchical analysis of risk factors, including smoking, age, sex, and menopause in women, was performed. The results revealed that non-smoking, aging (especially postmenopausal women), and low blood zinc concentrations were independent risk factors for the development of coronary heart disease (P ≤ 0.05, zinc ion concentration less than 13.82 ± 2.91). The findings strongly suggest that decreased zinc ion concentrations in the peripheral blood can be used as an independent risk factor for the prediction of coronary heart disease, especially in older patients, non-smokers, and women, in particular, postmenopausal women.

Understanding Circadian Mechanisms of Sudden Cardiac Death: A Report From the National Heart, Lung, and Blood Institute Workshop, Part 2: Population and Clinical Considerations

Sudden cardiac death (SCD) is the sudden, unexpected death due to abrupt loss of heart function secondary to cardiovascular disease. In certain populations living with cardiovascular disease, SCD follows a distinct 24-hour pattern in occurrence, suggesting day/night rhythms in behavior, the environment, and endogenous circadian rhythms result in daily spans of increased vulnerability. The National Heart, Lung, and Blood Institute convened a workshop, Understanding Circadian Mechanisms of Sudden Cardiac Death to identify fundamental questions regarding the role of the circadian rhythms in SCD. Part 2 summarizes research gaps and opportunities in the areas of population and clinical research identified in the workshop. Established research supports a complex interaction between circadian rhythms and physiological responses that increase the risk for SCD. Moreover, these physiological responses themselves are influenced by several biological variables, including the type of cardiovascular disease, sex, age, and genetics, as well as environmental factors. The emergence of new noninvasive biotechnological tools that continuously measure key cardiovascular variables, as well as the identification of biomarkers to assess circadian rhythms, hold promise for generating large-scale human data sets that will delineate which subsets of individuals are most vulnerable to SCD. Additionally, these data will improve our understanding of how people who suffer from circadian disruptions develop cardiovascular diseases that increase the risk for SCD. Emerging strategies to identify new biomarkers that can quantify circadian health (eg, environmental, behavioral, and internal misalignment) may lead to new interventions and therapeutic targets to prevent the progression of cardiovascular diseases that cause SCD.

Autonomic manifestations of epilepsy: emerging pathways to sudden death?

Epileptic networks are intimately connected with the autonomic nervous system, as exemplified by a plethora of ictal (during a seizure) autonomic manifestations, including epigastric sensations, palpitations, goosebumps and syncope (fainting). Ictal autonomic changes might serve as diagnostic clues, provide targets for seizure detection and help us to understand the mechanisms that underlie sudden unexpected death in epilepsy (SUDEP). Autonomic alterations are generally more prominent in focal seizures originating from the temporal lobe, demonstrating the importance of limbic structures to the autonomic nervous system, and are particularly pronounced in focal-to-bilateral and generalized tonic-clonic seizures. The presence, type and severity of autonomic features are determined by the seizure onset zone, propagation pathways, lateralization and timing of the seizures, and the presence of interictal autonomic dysfunction. Evidence is mounting that not all autonomic manifestations are linked to SUDEP. In addition, experimental and clinical data emphasize the heterogeneity of SUDEP and its infrequent overlap with sudden cardiac death. Here, we review the spectrum and diagnostic value of the mostly benign and self-limiting autonomic manifestations of epilepsy. In particular, we focus on presentations that are likely to contribute to SUDEP and discuss how wearable devices might help to prevent SUDEP.

Thyroid Hormone Plays an Important Role in Cardiac Function: From Bench to Bedside

Thyroid hormones (THs) are synthesized in the thyroid gland, and they circulate in the blood to regulate cells, tissues, and organs in the body. In particular, they exert several effects on the cardiovascular system. It is well known that THs raise the heart rate and cardiac contractility, improve the systolic and diastolic function of the heart, and decrease systemic vascular resistance. In the past 30 years, some researchers have studied the molecular pathways that mediate the role of TH in the cardiovascular system, to better understand its mechanisms of action. Two types of mechanisms, which are genomic and non-genomic pathways, underlie the effects of THs on cardiomyocytes. In this review, we summarize the current knowledge of the action of THs in the cardiac function, the clinical manifestation and parameters of their hemodynamics, and treatment principles for patients with hyperthyroid- or hypothyroid-associated heart disease. We also describe the cardiovascular drugs that induce thyroid dysfunction and explain the mechanism underlying the thyroid toxicity of amiodarone, which is considered the most effective antiarrhythmic agent. Finally, we discuss the recent reports on the involvement of thyroid hormones in the regulation of myocardial regeneration and metabolism in the adult heart.

Low-energy, single-pulse surface stimulation defibrillates large mammalian ventricles

BACKGROUND

Strong electric shocks are the gold standard for ventricular defibrillation but are associated with pain and tissue damage. We hypothesized that targeting the excitable gap (EG) of reentry with low-energy surface stimulation is a less damaging and painless alternative for ventricular defibrillation.

OBJECTIVE

The purpose of this study was to determine the conditions under which low-energy surface stimulation defibrillates large mammalian ventricles.

METHODS

Low-energy surface stimulation was delivered with five electrodes that were 7 cm long and placed 1-2 cm apart on the endocardial and epicardial surfaces of perfused pig left ventricle (LV). Rapid pacing (>4 Hz) was used to induce reentry from a single electrode. A 2 ms defibrillation pulse ≤0.5 A was delivered from all electrodes with a varied time delay from the end of the induction protocol (0.1-5 seconds). Optical mapping was performed and arrhythmia dynamics analyzed. For mechanistic insight, simulations of the VF induction and defibrillation protocols were performed in silico with an LV model emulating the experimental conditions and electrodes placed 0.25-2 cm apart.

RESULTS

In living LV, reentry was induced with varying complexity and dominant frequencies ranging between 3.5 to 6.2 Hz over 8 seconds postinitiation. Low-energy defibrillation was achieved with energy <60 mJ and electrode separations up to 2 cm for less complex arrhythmia. In simulations, defibrillation consistently occurred when stimulation captured >75% of the EG, which blocked reentry <2.9 mm in front of the leading reentrant wavefront.

CONCLUSION

Defibrillation with low-energy, single-pulse surface stimulation is feasible with energies below the human pain threshold (100 mJ). Optimal defibrillation occurs when arrhythmia complexity is minimal and electrodes capture >75% of the EG.

Endoplasmic reticulum stress-related secretory proteins as biomarkers of early myocardial ischemia-induced sudden cardiac deaths

Early myocardial ischemia-induced sudden cardiac deaths (EMI-SCD) remain a great diagnostic challenge for forensic pathologists due to no gross or non-specific histological pathology. The goal of this study was to assess whether three secretory proteins, related with cellular endoplasmic reticulum stress, can be applied in forensic diagnosis of EMI-SCD. These markers included LMAN2, CAPN-1, and VCP and were compared with two clinically used markers (CK-MB and cTnI). A total of 21 EMI-SCD cases with a mean age of 53.0 (± 10.5) years and a mean ischemia interval of < 2.77 (± 2.56) hours were collected. Another 23 cases (mean 44.6 ± 15.0 year old) that died from non-cardiac causes served as control. Enzyme-linked immunosorbent assay (ELISA) was performed to detect target proteins' serum concentrations in the EMI-SCD and control groups. We found that LMAN2, CAPN-1, and VCP were all significantly increased in the EMI-SCD group as compared with control serum, with the fold changes ranging from 1.48 (p = 0.0022, LMAN2), 1.33 (p = 0.041, CAPN-1), to 1.26 (p = 0.021, VCP), respectively. The concentrations of these proteins remained highly stable within 6 h and were not affected by death time, postmortem interval (< 4 h), age, and month at death. Receiver operating characteristic (ROC) curves showed that the areas under the curve (AUC) were 0.8178 (LMAN2), 0.6988 (CAPN-1), and 0.7267 (VCP), all of which were higher than CK-MB (AUC 0.5590) and cTn-I (AUC 0.5911). The diagnostic specificity (all above 60%) was obviously higher than CK-MB (43.48%) and cTnI (34.78%). In conclusion, LMAN-2, CAPN-1, and VCP could be stable serological biomarkers for diagnosis of EMI-SCD cases.

Inhibitory G-protein-mediated modulation of slow delayed rectifier potassium channels contributes to increased susceptibility to arrhythmogenesis in aging heart

BACKGROUND

Slow delayed rectifier potassium current (I_Ks) is an important component of repolarization reserve during sympathetic nerve excitement. However, little is known about age-related functional changes of I_Ks and its involvement in age-dependent arrhythmogenesis.

OBJECTIVE

The purpose of this study was to investigate age-related alteration of the I_Ks response to β-adrenergic receptor (βAR) activation.

METHODS

Dunkin-Hartley guinea pigs were used. Whole-cell patch-clamp recording was used to record K⁺ currents. Optical mapping of membrane potential was performed in ex vivo heart.

RESULTS

There was no difference in I_Ks density in ventricular cardiomyocytes between young and old guinea pigs. However, in contrast to I_Ks potentiation in young hearts, isoproterenol (ISO) evoked an acute inhibition on I_Ks in a concentration-dependent manner in old guinea pig hearts. The β₂AR antagonist, but not β₁AR antagonist, reversed the inhibitory response. Preincubation of cardiomyocytes with the inhibitory G protein (Gi) inhibitor pertussis toxin (PTX) also reversed the inhibitory response. In HEK293 cells cotransfected with cloned I_Ks channel and β₂AR, ISO enhanced the current but reduced it when cells were cotransfected with Gi2, and PTX restored the ISO-induced excitatory response. Moreover, in aging cardiomyocytes, Gβγ inhibitor gallein, PLC inhibitor U73122, or protein kinase C inhibitor Bis-1 prevented the reduction of I_Ks by ISO. Furthermore, cardiac-specific Gi2 overexpression in young guinea pigs predisposed the heart to ventricular tachyarrhythmias. PTX pretreatment protected the hearts from ventricular arrhythmias.

CONCLUSION

βAR activation acutely induces an inhibitory I_Ks response in aging guinea pig hearts through β₂AR-Gi signaling, which contributes to increased susceptibility to arrhythmogenesis in aging hearts.

Brain injury in extracorporeal cardiopulmonary resuscitation: translational to clinical research

The addition of extracorporeal membrane oxygenation (ECMO) to conventional cardiopulmonary resuscitation (CPR), termed extracorporeal cardiopulmonary resuscitation (ECPR), has significantly improved survival in selected patient populations. Despite this advancement, significant neurological impairment persists in approximately half of survivors. ECPR represents a potential advancement for patients who experience refractory cardiac arrest (CA) due to a reversible etiology and do not regain spontaneous circulation. Important risk factors for acute brain injury (ABI) in ECPR include lack of perfusion, reperfusion, and altered cerebral autoregulation. The initial hypoxic-ischemic injury caused by no-flow and low-flow states after CA and during CPR is compounded by reperfusion, hyperoxia during ECMO support, and nonpulsatile blood flow. Additionally, ECPR patients are at risk for Harlequin syndrome with peripheral cannulation, which can lead to preferential perfusion of cerebral vessels with deoxygenated blood. Lastly, the oxygenator membrane is prothrombotic and requires systemic anticoagulation. The two competing phenomena result in thrombus formation, hemolysis, and thrombocytopenia, increasing the risk of ischemic and hemorrhagic ABI. In addition to clinical studies, we assessed available ECPR animal models to identify the mechanisms underlying ABI at the cellular level. Standardized multimodal neurological monitoring may facilitate early detection of and intervention for ABI. With the increasing use of ECPR, it is critical to understand the pathophysiology of ABI, its prevention, and the management strategies for improving the outcomes of ECPR. Translational and clinical research focusing on acute ABI immediately after ECMO cannulation and its short- and long-term neurological outcomes are warranted.

[Clinical and anamnestic characteristics of patients with an implanted cardioverter-defibrillator in real clinical practice (data from the Kuzbass register)]

Aim      To study the consistency of the practice of management, selection and routing of patients at high risk of sudden cardiac death (SCD) selected for cardioverter-defibrillator implantation (CDI) with current clinical guidelines and to evaluate the quality of subsequent outpatient follow-up and treatment based on a retrospective analysis of clinical amnestic data from the Kuzbass Registry of Patients with CDI.Material and methods  The study was based on the Registry of Patients with Implanted Cardioverter Defibrillator and included successive data of 28 patients hospitalized to the Kizbass Cardiological Center from 2015 through 2019. Social and clinical amnestic characteristics, indications for CVI, and concomitant drug therapy were analyzed retrospectively. Statistical analyses were performed with the Statistica 10.0 software (Statsoft, USA).Results Median age of patients was 59 (53; 66) years; 239 (83.6 %) men were included; 29 (10.1%) people were employed, CHI was performed in 182 (63.6 %) patients for prevention of SCC, and for secondary prevention in 104 (36.4 %) patients. 208 (72.7 %) patients were diagnosed with ischemic heart disease (IHD), and 145 (67.9 %) of them underwent myocardial revascularization. Noncoronarogenic diseases were found in 78 (27.3 %) patients, and most of them were diagnosed with dilated cardiomyopathy. All patients had chronic heart failure (CHF); half of them had stage IIA CHF. Median left ventricular ejection fraction was 30 (25; 36,5) % according to echocardiography using the Simpson method. Comorbidity was found in 151 (52.8 %) patients. 128 (44.8%) patients received a triple neurohormonal blockade for CHF treatment; titration to target doses was not performed in any of them. Antiarrhythmics were administered to 150 (52.4 %) patients.Conclusion      According to the data from the Kuzbass Registry of CVI, the main patient cohort consisted of men of pension age with IHD and CHF. Before CVI, more than a half of them had not received an optimum drug therapy and not all of them had received target lesion revascularization. Creating and analysis of Registries of CHI patients is an effective method for identifying existing problems in patient management before CVI and for optimizing their subsequent follow-up and treatment.

Mito-targeted antioxidant prevents cardiovascular remodelling in spontaneously hypertensive rat by modulation of energy metabolism

Hypertension induced left ventricular hypertrophy (LVH) augments the risk of cardiovascular anomalies. Mitochondrial alterations result in oxidative stress, accompanied by decrease in fatty acid oxidation, leading to the activation of the hypertrophic program. Targeted antioxidants are expected to reduce mitochondrial reactive oxygen species more effectively than general antioxidants. This study was designed to assess whether the mito-targeted antioxidant, Mito-Tempol (Mito-TEMP) is more effective than the general oxidant, Tempol (TEMP) in reduction of hypertension and hypertrophy and prevention of shift in cardiac energy metabolism. Spontaneously hypertensive rats were administered either TEMP (20 mg/kg/day) or Mito-TEMP (2 mg/kg/day) intraperitoneally for 30 days. Post treatment, animals were subjected to 2D-echocardiography. Myocardial lysates were subjected to RPLC - LTQ-Orbitrap-MS analysis. Mid-ventricular sections were probed for markers of energy metabolism and fibrosis. The beneficial effect on cardiovascular structure and function was significantly higher for Mito-TEMP. Increase in mitochondrial antioxidants and stimulation of fatty acid metabolism; with significant improvement in cardiovascular function was apparent in spontaneously hypertensive rats (SHR) treated with Mito-TEMP. The study indicates that Mito-TEMP is superior to its non- targeted isoform in preventing hypertension induced LVH, and the beneficial effects on heart are possibly mediated by reversal of metabolic remodelling.

Potential role of an athlete-focused echocardiogram in sports eligibility

Sudden cardiac death (SCD) of an athlete is a rare but tragic event and sport activity might play a trigger role in athletes with underlying structural or electrical heart diseases. Preparticipation screenings (PPs) have been conceived for the potential to prevent SCD in young athletes by early identification of cardiac diseases. The European Society of Cardiology protocol for PPs includes history collection, physical examination and baseline electrocardiogram, while further examinations are reserved to individuals with abnormalities at first-line evaluation. Nevertheless, transthoracic echocardiography has been hypothesized to have a primary role in the PPs. This review aims to describe how to approach an athlete-focused echocardiogram, highlighting what is crucial to focus on for the different diseases (cardiomyopathies, valvulopathies, congenital heart disease, myocarditis and pericarditis) and when is needed to pay attention to overlap diagnostic zone ("grey zone") with the athlete's heart. Once properly tested, focused echocardiography by sports medicine physicians may become standard practice in larger screening practices, potentially available during first-line evaluation.

Sex Disparities in Sudden Cardiac Death

The overall incidence of sudden cardiac death is considerably lower among women than men, reflecting significant and often under-recognized sex differences. Women are older at time of sudden cardiac death, less likely to have a prior cardiac diagnosis, and less likely to have coronary artery disease identified on postmortem examination. They are more likely to experience their death at home, during sleep, and less likely witnessed. Women are also more likely to present in pulseless electrical activity or systole rather than ventricular fibrillation or ventricular tachycardia. Conversely, women are less likely to receive bystander cardiopulmonary resuscitation or receive cardiac intervention post-arrest. Underpinning sex disparities in sudden cardiac death is a paucity of women recruited to clinical trials, coupled with an overall lack of prespecified sex-disaggregated evidence. Thus, predominantly male-derived data form the basis of clinical guidelines. This review outlines the critical sex differences concerning epidemiology, cause, risk factors, prevention, and outcomes. We propose 4 broad areas of importance to consider: physiological, personal, community, and professional factors.

Discrete sites of frequent premature ventricular complexes cluster within the infarct border zone and coincide with high frequency of delayed afterdepolarizations under adrenergic stimulation

BACKGROUND

Sympathetic activation in ischemic heart disease can cause lethal arrhythmias. These often are preceded by premature ventricular complexes (PVCs), which at the cellular level could result from delayed afterdepolarizations.

OBJECTIVE

The purpose of this study was to identify and map vulnerable areas for arrhythmia initiation after myocardial infarction (MI) and to explore the link between PVCs and cellular events.

METHODS

Anterior-septal wall MI was induced by 120 minutes of coronary occlusion followed by reperfusion (27 MI and 16 sham pigs). After 4 weeks, EnSite™ electroanatomic mapping combined with imaging was performed to precisely locate PVC sites of origin and subsequently record monophasic action potentials. Cardiomyocytes were isolated from different regions to study regional cellular remodeling. Isoproterenol was used as a surrogate for adrenergic stimulation both in vivo and in cardiomyocytes.

RESULTS

PVCs originated from the MI border zone (BZ) and occurred at discrete areas with clusters of PVCs within the BZ. At these sites, frequent delayed afterdepolarizations and occasional associated spontaneous action potentials translating to a PVC were present. Cardiomyocytes isolated from the MI BZ exhibited more spontaneous action potentials than cardiomyocytes from remote regions. Sensitivity to adrenergic stimulation was increased in MI, in vivo and in cardiomyocytes. In awake, freely moving MI animals, frequent PVCs, ventricular arrhythmia, and sudden cardiac death occurred spontaneously at moderately elevated heart rates.

CONCLUSION

Post-MI, arrhythmias initiate from discrete vulnerable areas within the BZ, where delayed afterdepolarizations, related to increased adrenergic response of BZ cardiomyocytes, can generate PVCs.

Selvester score predicts implantable cardioverter defibrillator shocks in patients with non-ischemic cardiomyopathy

BACKGROUND

The implantable cardiac defibrillator is the cornerstone of prevention of sudden cardiac death in non-ischemic cardiomyopathy. The Selvester score, which is frequently investigated in ischemic cardiomyopathy, has not been investigated in the field of non-ischemic cardiomyopathy.

AIM

The aim of this study was to evaluate the Selvester score for determining appropriate implantable cardiac defibrillator shocks in non-ischemic cardiomyopathy patients.

MATERIALS AND METHODS

In all, 131 non-ischemic cardiomyopathy patients were included in the study. A simplified Selvester score was calculated from ECG data. Patients were divided into two groups according to whether they received ICD shock.

RESULTS

Of the patients, 28.2% received appropriate implantable cardiac defibrillator shock. The Selvester score was significantly higher in patients receiving appropriate shock when compared to patients with no implantable cardiac defibrillator shocks (8.8 ± 4.6 vs 7.2 ± 3.3, P = .040). The median QRS duration was significantly longer in patients receiving appropriate shock than in patients with no shocks (130.14 ± 35.08 ms vs 120.12 ± 20.57 ms, P = .045). We determined that the cutoff value for the Selvester score to predict ICD shocks was 6.5 with a sensitivity of 72.0% and a specificity of 83% (AUC = 0.717; %95 GA: 0.627-0.807, P < .001).

CONCLUSION

Selvester score was higher in patients receiving appropriate shock than in patients who did not receive any implantable cardiac defibrillator shock. From this study, the Selvester score is associated with the risk of ventricular tachycardia/ventricular fibrillation in non-ischemic cardiomyopathy so that careful attention is necessary to manage the patients with high Selvester score.

Coronary angiography in patients after cardiac arrest without ST-elevation myocardial infarction : A retrospective cohort analysis

BACKGROUND

Coronary artery disease (CAD) is the most common cause of sudden cardiac arrest (SCA). Although coronary angiography (CAG) should be performed also in the absence of ST-elevation (STE) after sustained return of spontaneous circulation (ROSC), this recommendation is not well implemented in daily routine.

METHODS

A retrospective database analysis was conducted in a tertiary care center between January 2005 and December 2014. We included all SCA patients aged ≥ 18 years with presumed cardiac cause and sustained ROSC in the absence of STE at hospital admission. The rate and timing of CAG were defined as the primary endpoints. As secondary endpoints, the reasons pro and contra CAG were analyzed. Furthermore, we observed if the signs and symptoms used for decision making occurred more often in patients with treatable CAD.

RESULTS

We included 645 (53.6%) of the 1203 screened patients, CAG was performed in 343 (53.2%) patients with a diagnosis of occlusive CAD in 214 (62.4%) patients. Of these, 151 (71.0%) patients had occlusive CAD treated with coronary intervention, thrombus aspiration, or coronary artery bypass grafting. In an adjusted binomial logistic regression analysis, age ≥ 70 years, female sex, non-shockable rhythms, and cardiomyopathy were associated with withholding of CAG. In patients diagnosed and treated with occlusive CAD, initially shockable rhythms, previously diagnosed CAD, hypertension, and smoking were found more often.

CONCLUSION

Although selection bias is unavoidable due to the retrospective design of this study, a high proportion of the examined patients had occlusive CAD. The criteria used for patient selection may be suboptimal.

Rethinking adherence to home care in heart failure: the lessons learned from Diego Maradona's death

Heart failure (HF) is complex and prevalent cardiac condition associated with high hospitalization rates and mortality. Early recognition and risk categorization of vulnerable patients is essential prior to discharge. Following the recent death of Diego A. Maradona, the 60 year old universally known soccer player, we highlighted critical aspects of ambulatory home care after hospital discharge. We raised three relevant clinical questions regarding home care services: its effectiveness in patients with HF while also providing practical summary tables for the identification of high-risk patients with HF and critical elements for an effective ambulatory home care delivery. A comprehensive home care program for high-risk patients with HF requires the coordination of multiple health services, including personal and nursing care, cardiac monitoring, physio- and occupational therapy, pharmacists, as well as nutritional and emotional support to avoid recurrent hospitalizations while improving clinical outcomes.

[Sudden death in school-aged children at physical exercise: forensic diagnosis]

OBJECTIVE

Acomprehensive forensic study of cases of sudden death of school-age children during physical exertion and sports. Investigated 9 cases of sudden death of children aged 8 to 17 years that occurred during exercise. It was studied anthropometric indicators, histological and biochemical studies to identify changes in internal organs and the cardiovascular system. The forensic medical characteristics of sudden death cases of schoolchildren are given. Along with the constitutional features, the characteristic changes in some tissues and internal organs in particular the heart and blood vessels were determined. The data obtained make it possible to develop an algorithm and propose a methodological approach for diagnosing sudden death of school-age children. The results of the study can be used as additional forensic criteria for assessing the risk of sudden death of children during physical activity.