Sudden cardiac arrest in infants and children: proposal for a diagnostic workup to identify the etiology. An 18-year multicenter evaluation in the Netherlands.

Sudden cardiac arrest (SCA) studies are often population-based, limited to sudden cardiac death, and excluding infants. To guide prevention opportunities, it is essential to be informed of pediatric SCA etiologies. Unfortunately, etiologies frequently remain unresolved. The objectives of this study were to determine paediatric SCA etiology, and to evaluate the extent of post-SCA investigations and to assess the performance of previous cardiac evaluation in detecting conditions predisposing to SCA. In a retrospective cohort (2002-2019), all children 0-18 years with out-of-hospital cardiac arrest (OHCA) referred to Erasmus MC Sophia Children's Hospital or the Amsterdam UMC (tertiary-care university hospitals), with cardiac or unresolved etiologies were eligible for inclusion. SCA etiologies, cardiac and family history and etiologic investigations in unresolved cases were assessed. The etiology of arrest could be determined in 52% of 172 cases. Predominant etiologies in children ≥ 1 year (n = 99) were primary arrhythmogenic disorders (34%), cardiomyopathies (22%) and unresolved (32%). Events in children < 1 year (n = 73) were largely unresolved (70%) or caused by cardiomyopathy (8%), congenital heart anomaly (8%) or myocarditis (7%). Of 83 children with unresolved etiology a family history was performed in 51%, an autopsy in 51% and genetic testing in 15%. Pre-existing cardiac conditions presumably causative for SCA were diagnosed in 9%, and remained unrecognized despite prior evaluation in 13%. CONCLUSION: SCA etiology remained unresolved in 83 of 172 cases (48%) and essential diagnostic investigations were often not performed. Over one-fifth of SCA patients underwent prior cardiac evaluation, which did not lead to recognition of a cardiac condition predisposing to SCA in all of them. The diagnostic post-SCA approach should be improved and the proposed standardized pediatric post-SCA diagnostics protocol may ensure a consistent and systematic evaluation process increasing the diagnostic yield. WHAT IS KNOWN: • Arrests in infants remain unresolved in most cases. In children > 1 year, predominant etiologies are primary arrhythmia disorders, cardiomyopathy and myocarditis. • Studies investigating sudden cardiac arrest are often limited to sudden cardiac death (SCD) in 1 to 40 year old persons, excluding infants and successfully resuscitated children. WHAT IS NEW: • In patients with unresolved SCA events, the diagnostic work up was often incompletely performed. • Over one fifth of victims had prior cardiac evaluation before the arrest, with either a diagnosed cardiac condition (9%) or an unrecognized cardiac condition (13%).

Ethical use of artificial intelligence to prevent sudden cardiac death: an interview study of patient perspectives.

BACKGROUND: The emergence of artificial intelligence (AI) in medicine has prompted the development of numerous ethical guidelines, while the involvement of patients in the creation of these documents lags behind. As part of the European PROFID project we explore patient perspectives on the ethical implications of AI in care for patients at increased risk of sudden cardiac death (SCD). AIM: Explore perspectives of patients on the ethical use of AI, particularly in clinical decision-making regarding the implantation of an implantable cardioverter-defibrillator (ICD). METHODS: Semi-structured, future scenario-based interviews were conducted among patients who had either an ICD and/or a heart condition with increased risk of SCD in Germany (n = 9) and the Netherlands (n = 15). We used the principles of the European Commission's Ethics Guidelines for Trustworthy AI to structure the interviews. RESULTS: Six themes arose from the interviews: the ability of AI to rectify human doctors' limitations; the objectivity of data; whether AI can serve as second opinion; AI explainability and patient trust; the importance of the 'human touch'; and the personalization of care. Overall, our results reveal a strong desire among patients for more personalized and patient-centered care in the context of ICD implantation. Participants in our study express significant concerns about the further loss of the 'human touch' in healthcare when AI is introduced in clinical settings. They believe that this aspect of care is currently inadequately recognized in clinical practice. Participants attribute to doctors the responsibility of evaluating AI recommendations for clinical relevance and aligning them with patients' individual contexts and values, in consultation with the patient. CONCLUSION: The 'human touch' patients exclusively ascribe to human medical practitioners extends beyond sympathy and kindness, and has clinical relevance in medical decision-making. Because this cannot be replaced by AI, we suggest that normative research into the 'right to a human doctor' is needed. Furthermore, policies on patient-centered AI integration in clinical practice should encompass the ethics of everyday practice rather than only principle-based ethics. We suggest that an empirical ethics approach grounded in ethnographic research is exceptionally well-suited to pave the way forward.

Validation of the ARIC prediction model for sudden cardiac death in the European population: The ESCAPE-NET project.

BACKGROUND: Sudden cardiac death is responsible for 10% to 20% of all deaths in Europe. The current study investigates how well the risk of sudden cardiac death can be predicted. To this end, we validated a previously developed prediction model for sudden cardiac death from the Atherosclerosis Risk in Communities study (USA). METHODS: Data from participants of the Copenhagen City Heart Study (CCHS) (n=9988) was used to externally validate the previously developed prediction model for sudden cardiac death. The model's performance was assessed through discrimination (C-statistic) and calibration by the Hosmer-Lemeshow goodness-of-fit (HL) statistics suited for censored data and visual inspection of calibration plots. Additional validation was performed using data from the Hoorn Study (N=2045), employing the same methods. RESULTS: During ten years of follow-up of CCHS participants (mean age: 58.7 years, 56.2% women), 425 experienced SCD (4.2%). The prediction model showed good discrimination for sudden cardiac death risk (C-statistic: 0.81, 95% CI: 0.79-0.83). Calibration was robust (HL statistic: P=0.8). Visual inspection of the calibration plot showed that the calibration could be improved. Sensitivity was 89.8%, and specificity was 60.6%. The positive and negative predictive values were 10.1% and 99.2%. Model performance was similar in the Hoorn Study (C-statistic: 0.81, 95% CI: 0.77-0.85 and the HL statistic: 1.00). CONCLUSION: Our study showed that the previously developed prediction model in North American adults performs equally well in identifying those at risk for sudden cardiac death in a general North-West European population. However, the positive predictive value is low.

The opioid tramadol blocks the cardiac sodium channel Nav1.5 in HEK293 cells.

AIMS: Opioids are associated with increased risk of sudden cardiac death. This may be due to their effects on the cardiac sodium channel (Nav1.5) current. In the present study, we aim to establish whether tramadol, fentanyl, or codeine affects Nav1.5 current. METHODS AND RESULTS: Using whole-cell patch-clamp methodology, we studied the effects of tramadol, fentanyl, and codeine on currents of human Nav1.5 channels stably expressed in HEK293 cells and on action potential (AP) properties of freshly isolated rabbit ventricular cardiomyocytes. In fully available Nav1.5 channels (holding potential -120 mV), tramadol exhibited inhibitory effects on Nav1.5 current in a concentration-dependent manner with an IC50 of 378.5 ± 33.2 µm. In addition, tramadol caused a hyperpolarizing shift of voltage-gated (in)activation and a delay in recovery from inactivation. These blocking effects occurred at lower concentrations in partially inactivated Nav1.5 channels: during partial fast inactivation (close-to-physiological holding potential -90 mV), IC50 of Nav1.5 block was 4.5 ± 1.1 µm, while it was 16 ± 4.8 µm during partial slow inactivation. The tramadol-induced changes on Nav1.5 properties were reflected by a reduction in AP upstroke velocity in a frequency-dependent manner. Fentanyl and codeine had no effect on Nav1.5 current, even when tested at lethal concentrations. CONCLUSION: Tramadol reduces Nav1.5 currents, in particular, at close-to-physiological membrane potentials. Fentanyl and codeine have no effects on Nav1.5 current.

Towards trust-based governance of health data research.

Developments in medical big data analytics may bring societal benefits but are also challenging privacy and other ethical values. At the same time, an overly restrictive data protection regime can form a serious threat to valuable observational studies. Discussions about whether data privacy or data solidarity should be the foundational value of research policies, have remained unresolved. We add to this debate with an empirically informed ethical analysis. First, experiences with the implementation of the General Data Protection Regulation (GDPR) within a European research consortium demonstrate a gap between the aims of the regulation and its effects in practice. Namely, strictly formalised data protection requirements may cause routinisation among researchers instead of substantive ethical reflection, and may crowd out trust between actors in the health data research ecosystem; while harmonisation across Europe and data sharing between countries is hampered by different interpretations of the law, which partly stem from different views about ethical values. Then, building on these observations, we use theory to argue that the concept of trust provides an escape from the privacy-solidarity debate. Lastly, the paper details three aspects of trust that can help to create a responsible research environment and to mitigate the encountered challenges: trust as multi-agent concept; trust as a rational and democratic value; and trust as method for priority setting. Mutual cooperation in research-among researchers and with data subjects-is grounded in trust, which should be more explicitly recognised in the governance of health data research.

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.

Risk of out-of-hospital cardiac arrest in patients with epilepsy and users of antiepileptic drugs.

AIMS: A few studies suggested that epilepsy and antiepileptic drugs with sodium channel-blocking properties were independently associated with out-of-hospital cardiac arrest (OHCA). However, these findings have not yet been replicated. METHODS: Using Danish registries, we conducted a nested case-control study in a cohort of individuals between 1 June 2001 and 31 December 2015. Cases were defined as OHCA from presumed cardiac causes, and were matched with non-OHCA-controls based on sex, and age on the date of OHCA. Exposure of interest was epilepsy or antiepileptic drug use. To study the association between individual antiepileptic drug use and the rate of OHCA, we compared each antiepileptic drug with valproic acid. Cox regression with time-dependent covariates was conducted to calculate hazard ratio (HR) and 95% confidence interval (CI). RESULTS: We identified 35 195 OHCA-cases and 351 950 matched non-OHCA controls. Epilepsy (cases: 3.58%, controls: 1.60%) was associated with increased rate of OHCA compared with the general population (HR: 1.76, 95%CI: 1.64-1.88) when common OHCA risk factors were taken into account. When we studied antiepileptic drug use, we found that 2 antiepileptic drugs without sodium channel blockage, clonazepam (HR: 1.88, 95%CI: 1.45-2.44) and pregabalin (HR: 1.33, 95%CI: 1.05-1.69), were associated with OHCA, whereas none of the antiepileptic drugs with sodium channel blockage were associated with OHCA. CONCLUSION: Epilepsy is associated with increased rate of OHCA. Our findings do not support a possible association between antiepileptic drugs with sodium channel-blocking properties and OHCA.

Opioid use is associated with increased out-of-hospital cardiac arrest risk among 40 000-cases across two countries.

AIMS: Opioid use has substantially increased in the last decade and is associated with overdose mortality, but also with increased mortality from cardiovascular causes. This finding may partly reflect an association between opioids and out-of-hospital cardiac arrest (OHCA). Therefore, we aimed to investigate OHCA-risk of opioids in the community. METHODS: We conducted 2 population-based case-control studies separately in the Netherlands (2009-2018) and Denmark (2001-2015). Cases were individuals who experienced OHCA of presumed cardiac cause. Each case was matched with up to 5 non-OHCA-controls according to age, sex and OHCA-date. Conditional logistic regression analysis was used to calculate odds ratios (ORs) and 95% confidence intervals (CIs). RESULTS: We included 5473 OHCA-cases matched with 21 866 non-OHCA-controls in the Netherlands, and 35 017 OHCA-cases matched with 175 085 non-OHCA-controls in Denmark. We found that use of opioids (the Netherlands: cases: 5.4%, controls: 1.8%; Denmark: cases: 11.9%, controls: 4.4%) was associated with increased OHCA-risk in both regions (the Netherlands: OR 2.1 [95% CI 1.8-2.5]; Denmark: OR 1.8 [95% CI 1.5-2.1]). The association was observed in both sexes, and in individuals with cardiovascular disease (the Netherlands: OR 1.8 [95% CI 1.5-2.1]; Denmark: OR 1.6 [95% CI 1.5-1.7]) or without (the Netherlands: OR 3.4 [95% CI: 2.4-4.8], Pinteraction  < .0001; Denmark: OR 2.3 [95% CI: 2.0-2.5], Pinteraction  < .0001). CONCLUSION: Use of opioids is associated with increased OHCA-risk in both sexes, independently of concomitant cardiovascular disease. These findings should be considered when evaluating the harms and benefits of treatment with opioids.

Risk of out-of-hospital cardiac arrest in antidepressant drug users.

Conflicting results have been reported regarding the association between antidepressant use and out-of-hospital cardiac arrest (OHCA) risk. We investigated whether the use of antidepressants is associated with OHCA. METHODS: We conducted a nationwide nested case-control study to assess the association of individual antidepressant drugs within drug classes with the hazard of OHCA. Cases were defined as OHCA from presumed cardiac causes. Cox regression with time-dependent exposure and time-dependent covariates was conducted to calculate hazard ratios (HR) and 95% confidence intervals (95% CIs) overall and in subgroups defined by established cardiac disease and cardiovascular risk factors. Also, we studied antidepressants with and without sodium channel blocking or potassium channel blocking properties separately. RESULTS: During the study period from 2001 to 2015 we observed 10 987 OHCA cases, and found increased OHCA rate for high-dose citalopram (>20 mg) and high-dose escitalopram (>10 mg; HR:1.46 [95% CI:1.27-1.69], HR:1.43 [95% CI:1.16-1.75], respectively) among selective serotonin reuptake inhibitors (reference drug sertraline), and for high-dose mirtazapine (>30; HR:1.59 [95% CI:1.18-2.14]) among the serotonin-norepinephrine reuptake inhibitors or noradrenergic and specific serotonergic antidepressants (reference drug duloxetine). Among tricyclic antidepressants (reference drug amitriptyline), no drug was associated with significantly increased OHCA rate. Increased OHCA rate was found for antidepressants with known potassium channel blocking properties (HR:1.14 [95% CI:1.05-1.23]), but for not those with sodium channel blocking properties. Citalopram, although not statistically significant, and mirtazapine were associated with increased OHCA rate in patients without cardiac disease and cardiovascular risk factors. CONCLUSION: Our findings indicate that careful titration of citalopram, escitalopram and mirtazapine dose may have to be considered due to drug safety issues.

Out-of-hospital cardiac arrest and differential risk of cardiac and non-cardiac QT-prolonging drugs in 37 000 cases.

AIMS: Drugs that prolong the QT interval, either by design (cardiac QT-prolonging drugs: anti-arrhythmics) or as off-target effect (non-cardiac QT-prolonging drugs), may increase the risk of ventricular arrhythmias and out-of-hospital cardiac arrest (OHCA). Risk mitigation measures were instituted, in particular, surrounding prescription of cardiac QT-prolonging drugs. We studied OHCA risk of both drug types in current clinical practice. METHODS: Using data from large population-based OHCA registries in the Netherlands and Denmark, we conducted two independent case-control studies. OHCA cases with presumed cardiac causes were matched on age/sex/index date with up to five non-OHCA controls. We calculated odds ratios (ORs) for the association of cardiac or non-cardiac QT-prolonging drugs with OHCA risk using conditional logistic regression analyses. RESULTS: We identified 2503 OHCA cases and 10 543 non-OHCA controls in the Netherlands, and 35 017 OHCA cases and 175 085 non-OHCA controls in Denmark. Compared to no use of QT-prolonging drugs, use of non-cardiac QT-prolonging drugs (Netherlands: cases: 3.0%, controls: 1.9%; Denmark: cases: 14.9%, controls: 7.5%) was associated with increased OHCA risk (Netherlands: OR 1.37 [95% CI: 1.03-1.81]; Denmark: OR 1.63 [95% CI: 1.57-1.70]). The association between cardiac QT-prolonging drugs (Netherlands: cases: 4.0%, controls: 2.5%; Denmark: cases: 2.1%, controls: 0.9%) and OHCA was weaker (Netherlands: OR 1.17 [95% CI: 0.92-1.50]; Denmark: OR 1.21 [95% CI: 1.09-1.33]), although users of cardiac QT-prolonging drugs had more medication use and comorbidities associated with OHCA risk than users of non-cardiac QT-prolonging drugs. CONCLUSION: In clinical practice, cardiac QT-prolonging drugs confer lower OHCA risk than non-cardiac QT-prolonging drugs, although users of the former have higher a priori risk. This is likely due to risk mitigation measures surrounding prescription of cardiac QT-prolonging drugs.

Multiple categories of non-cardiac QT-prolonging drugs are associated with increased risk of out-of-hospital cardiac arrest: real-world data from a population-based study.

AIM: Drugs causing QT-prolongation as off-target effect [non-cardiac QT-prolonging drugs (QT-drugs)] increase the risk of out-of-hospital cardiac arrest (OHCA). Such drugs are categorized in multiple clinically widely used CredibleMeds.org lists. Category 1 ('known risk of Torsade de Pointes') and category 2 ('possible risk of Torsade de Pointes') are of particular clinical relevance. However, a category-stratified analysis of OHCA-risk is presently unavailable. METHODS AND RESULTS: We conducted a case-control study with OHCA-cases from presumed cardiac causes included from the ARREST registry in the Netherlands (2009-2018) that was specifically designed to study OHCA, and age/sex/OHCA-date matched non-OHCA-controls. Adjusted odds ratios for OHCA (ORadj) of QT-drugs from categories 1 or 2 were calculated, using conditional logistic regression. Stratified analysis was performed according to sex, age, and presence of cardiovascular drugs (proxy for cardiovascular disease). We included 5473 OHCA-cases (68.8 years, 69.9% men) and matched them to 20 866 non-OHCA-controls. Compared with no use of non-cardiac QT-drugs, drugs of both categories were associated with increased OHCA-risk, but seemingly weaker for category 2 {category 1: case 3.2%, control 1.4%, ORadj 1.7 [95% confidence interval (CI): 1.3-2.1]}; [category 2: case 7.3%, control 4.0%, ORadj 1.4 (95% CI: 1.2-1.6)]. The increased risk occurred in men and women, at all ages (highest in patients aged ≤50 years), and both in the presence or absence of cardiovascular drug use. CONCLUSION: Both category 1 and category 2 QT-drugs are associated with increased OHCA-risk in both sexes, at all ages, and in patients taking or not taking cardiovascular drugs.

Is the Association Between Education and Sympathovagal Balance Mediated by Chronic Stressors?

BACKGROUND: This study investigated whether raised chronic stress in low education groups contributes to education differences in cardiovascular disease by altering sympathovagal balance. METHODS: This study included cross-sectional data of 10,202 participants from the multi-ethnic, population-based HELIUS-study. Sympathovagal balance was measured by baroreflex sensitivity (BRS), the standard deviation of the inter-beat interval (SDNN) and the root mean square of successive differences between normal heartbeats (RMSSD). The associations between chronic stressors (work, home, psychiatric, financial, negative life events, lack of job control and perceived discrimination) in a variety of domains and BRS, SDNN and RMSSD were assessed using linear regression, adjusted for age, ethnicity, waist-to-hip ratio and pack-years smoked. Mediation analysis was used to assess the contribution of chronic stress to the association between education and sympathovagal balance. RESULTS: Modest but significant associations were observed between financial stress and BRS and SDNN in women, but not in RMSSD nor for any outcome measure in men. Women with the highest category of financial stress had 0.55% lower BRS (ms/mmHg; ß = -0.055; CI = -0.098, -0.011) and 0.61% lower SDNN (ms; ß = -0.061; CI = -0.099, -0.024) than those in the lowest category. Financial stress in women contributed 7.1% to the association between education and BRS, and 13.8% to the association between education and SDNN. CONCLUSION: No evidence was found for the hypothesized pathway in which sympathovagal balance is altered by chronic stress, except for a small contribution of financial stress in women.

Socioeconomic Differences in Sympathovagal Balance: The Healthy Life in an Urban Setting Study.

OBJECTIVE: Alterations in sympathovagal balance are associated with cardiovascular disease. If sympathovagal balance differs across socioeconomic groups, it may reflect a mechanism through which disparities in cardiovascular disease occur. We therefore assessed the association between education and occupation with measures of sympathovagal balance in a large multiethnic sample. METHODS: We included cross-sectional data of 10,202 South Asian Surinamese, African Surinamese, Ghanaian, Turkish, Moroccan, and Dutch-origin participants from the Healthy Life in an Urban Setting study. Sympathovagal balance was measured by baroreflex sensitivity (BRS) and the standard deviation of the interbeat interval, calculated from changes in blood pressure and interbeat intervals, from 5-minute recordings. We calculated geometric means and estimated the relative index of inequality, using age- and ethnicity-adjusted linear regression, to quantify the association between education and occupation and sympathovagal balance. In addition, we assessed whether the association was consistent across ethnic groups. RESULTS: The geometric means of BRS ranged from 8.16 ms/mm Hg (confidence interval [CI] = 7.91-8.43 ms/mm Hg) in low-educated to 14.00 ms/mm Hg (CI = 13.53-14.48 ms/mm Hg) in highly educated women, and from 8.32 ms/mm Hg (CI, 7.97-8.69 ms/mm Hg) in low-educated to 12.25 ms/mm Hg (CI = 11.86-12.66 ms/mm Hg) in highly educated men. High education and occupation were statistically significantly associated with higher BRS and standard deviation of the interbeat interval. Compared with the participants of Dutch origin, a pattern of weaker associations was found in the Surinamese and Ghanaian ethnic groups, but not the Turkish and Moroccan groups. CONCLUSIONS: There is a clear socioeconomic gradient in measures of sympathovagal balance, indicating that sympathovagal balance may play a role in socioeconomic disparities in cardiovascular morbidity and mortality.

Sulfonylurea antidiabetics are associated with lower risk of out-of-hospital cardiac arrest: Real-world data from a population-based study.

AIMS: Out-of-hospital cardiac arrest (OHCA) mostly results from ventricular tachycardia/ventricular fibrillation (VT/VF), often triggered by acute myocardial infarction (AMI). Sulfonylurea (SU) antidiabetics can block myocardial ATP-regulated K+ channels (KATP channels), activated during AMI, thereby modulating action potential duration (APD). We studied whether SU drugs impact on OHCA risk, and whether these effects are related to APD changes. METHODS: We conducted a population-based case-control study in 219 VT/VF-documented OHCA cases with diabetes and 697 non-OHCA controls with diabetes. We studied the association of SU drugs (alone or in combination with metformin) with OHCA risk compared to metformin monotherapy, and of individual SU drugs compared to glimepiride, using multivariable logistic regression analysis. We studied the effects of these drugs on APD during simulated ischaemia using patch-clamp studies in human induced pluripotent stem cell-derived cardiomyocytes. RESULTS: Compared to metformin, use of SU drugs alone or in combination with metformin was associated with reduced OHCA risk (ORSUdrugs-alone 0.6 [95% CI 0.4-0.9], ORSUdrugs + metformin 0.6 [95% CI 0.4-0.9]). We found no differences in OHCA risk between SU drug users who suffered OHCA inside or outside the context of AMI. Reduction of OHCA risk compared to glimepiride was found with gliclazide (ORadj 0.5 [95% CI 0.3-0.9]), but not glibenclamide (ORadj 1.3 [95% CI 0.6-2.7]); for tolbutamide, the association with reduced OHCA risk just failed to reach statistical significance (ORadj 0.6 [95% CI 0.3-1.002]). Glibenclamide attenuated simulated ischaemia-induced APD shortening, while the other SU drugs had no effect. CONCLUSIONS: SU drugs were associated with reduced OHCA risk compared to metformin monotherapy, with gliclazide having a lower risk than glimepiride. The differential effects of SU drugs are not explained by differential effects on APD.

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.

The ß-angle can help guide clinical decisions in the diagnostic work-up of patients suspected of Brugada syndrome: a validation study of the ß-angle in determining the outcome of a sodium channel provocation test.

AIMS: In patients with Brugada syndrome (BrS) but without spontaneous Type-1 electrocardiogram, several electrocardiographic characteristics have been studied, including the ß-angle. Previous studies suggested that the ß-angle might be useful in distinguishing BrS-patients from patients with only suggestive repolarization patterns without performing sodium channel blocker provocation testing. In this study, we aimed to determine the diagnostic value of the ß-angle in patients suspected of BrS. METHODS AND RESULTS: A large cohort (n = 1430) of consecutive patients who underwent provocation testing was evaluated. ß-angles were measured in leads V1, V2, and their corresponding positions over the second and third intercostal space. Receiver-operating characteristic curves were constructed and the diagnostic accuracy of previously reported ß-angle cut-offs were calculated and evaluated. The importance of the ß-angle for predicting the provocation test outcome was determined using a prediction model constructed with logistic regression. The optimum ß-angle cut-off in our cohort for ruling out a positive provocation test was 15°; sensitivities were 80-98% and negative predictive values were 79-96% among the right precordial leads. Previously reported ß-angle cut-offs performed less well, indicated by lower Youden indices. In the optimism-corrected prediction model [C-statistic: 0.78 (95% CI: 0.75-0.81)], the ß-angle had large value (Z-score: 2.1-10.3) and aided construction of a nomogram to predict test outcome. CONCLUSION: To predict the outcome of provocation testing for BrS, the ß-angle alone does not demonstrate strong diagnostic characteristics. However, the ß-angle is an important variable to predict provocation test outcome and thus has added value.

Health data research on sudden cardiac arrest: perspectives of survivors and their next-of-kin.

BACKGROUND: Consent for data research in acute and critical care is complex as patients become at least temporarily incapacitated or die. Existing guidelines and regulations in the European Union are of limited help and there is a lack of literature about the use of data from this vulnerable group. To aid the creation of a patient-centred framework for responsible data research in the acute setting, we explored views of patients and next-of-kin about the collection, storage, sharing and use of genetic and health-related data for observational research. METHODS: We conducted qualitative interviews (n = 19) with Dutch sudden cardiac arrest survivors who donated clinical and socio-economic data and genetic samples to research. We also interviewed their next-of-kin. Topics were informed by ethics literature and we used scenario-sketches to aid discussion of complex issues. RESULTS: Sudden cardiac arrest survivors displayed limited awareness of their involvement in health data research and of the content of their given consent. We found that preferences regarding disclosure of clinically actionable genetic findings could change over time. When data collection and use were limited to the medical realm, patients trusted researchers to handle data responsibly without concern for privacy or other risks. There was no consensus as to whether deferred consent should be explicitly asked from survivors. If consent is asked, this would ideally be done a few months after the event when cognitive capacities have been regained. Views were divided about the need to obtain proxy consent for research with deceased patients' data. However, there was general support for the disclosure of potentially relevant post-mortem genetic findings to relatives. CONCLUSIONS: Sudden cardiac arrest patients' donation of data for research was grounded in trust in medicine overall, blurring the boundary between research and care. Our findings also highlight questions about the acceptability of a one-time consent and about responsibilities of patients, researchers and ethics committees. Finally, further normative investigation is needed regarding the (continued) use of participants' data after death, which is of particular importance in this setting. Our findings are thought to be of relevance for other acute and life-threatening illnesses as well.

Left Axis Deviation in Brugada Syndrome: Vectorcardiographic Evaluation during Ajmaline Provocation Testing Reveals Additional Depolarization Abnormalities.

Patients with Brugada syndrome (BrS) can show a leftward deviation of the frontal QRS-axis upon provocation with sodium channel blockers. The cause of this axis change is unclear. In this study, we aimed to determine (1) the prevalence of this left axis deviation and (2) to evaluate its cause, using the insights that could be derived from vectorcardiograms. Hence, from a large cohort of patients who underwent ajmaline provocation testing (n = 1430), we selected patients in whom a type-1 BrS-ECG was evoked (n = 345). Depolarization and repolarization parameters were analyzed for reconstructed vectorcardiograms and were compared between patients with and without a >30° leftward axis shift. We found (1) that the prevalence of a left axis deviation during provocation testing was 18% and (2) that this left axis deviation was not explained by terminal conduction slowing in the right ventricular outflow tract (4th QRS-loop quartile: +17 ± 14 ms versus +13 ± 15 ms, nonsignificant) but was associated with a more proximal conduction slowing (1st QRS-loop quartile: +12[8;18] ms versus +8[4;12] ms, p < 0.001 and 3rd QRS-loop quartile: +12 ± 10 ms versus +5 ± 7 ms, p < 0.001). There was no important heterogeneity of the action potential morphology (no difference in the ventricular gradient), but a left axis deviation did result in a discordant repolarization (spatial QRS-T angle: 122[59;147]° versus 44[25;91]°, p < 0.001). Thus, although the development of the type-1 BrS-ECG is characterized by a terminal conduction delay in the right ventricle, BrS-patients with a left axis deviation upon sodium channel blocker provocation have an additional proximal conduction slowing, which is associated with a subsequent discordant repolarization. Whether this has implications for risk stratification is still undetermined.

High haemoglobin A1c level is a possible risk factor for ventricular fibrillation in sudden cardiac arrest among non-diabetic individuals in the general population.

AIMS: This study aimed to establish whether higher levels of glycated haemoglobin (HbA1c) are associated with increased sudden cardiac arrest (SCA) risk in non-diabetic individuals. METHODS AND RESULTS: Case-control study in non-diabetic individuals (HbA1c < 6.5%) in the Netherlands. Cases were SCA patients with electrocardiogram (ECG)-documented ventricular fibrillation (VF, the predominant cause of SCA) and HbA1c measurements immediately after VF, prospectively included in September 2009-December 2012. Controls (up to 10 per case) were age/sex-matched non-SCA individuals, included in July 2006-November 2007. We studied 306 cases (56.4 ± 6.8 years, 79.1% male) and 1722 controls (54.0 ± 6.8 years, 64.8% male). HbA1c levels were higher in cases than in controls (5.8 ± 0.3% vs. 5.4 ± 0.3%, P < 0.001). The proportion of increased HbA1c (≥5.7%) was 63.1% in cases and 19.3% in controls (P < 0.001). Multivariate regression models indicated that increased HbA1c was associated with a > six-fold increased VF risk [adjusted odds ratio (ORadj) 6.74 (5.00-9.09)] and that 0.1% increase in HbA1c level was associated with 1.4-fold increase in VF risk, independent of concomitant cardiovascular risk factors. Increased VF risk at higher HbA1c is associated with acute myocardial infarction (MI) as cause of VF [OR 1.14 (1.04-1.24)], but the association between HbA1c and VF was similar in non-MI patients [OR 1.32 (1.21-1.44)] and MI patients [OR 1.47 (1.37-1.58)]. CONCLUSION: Among non-diabetic individuals, risk of VF increased with rising HbA1c levels, independent of concomitant cardiovascular disease. Future studies should establish whether HbA1c level may be used as biomarker to recognize individuals at risk for VF.

Association of beta-blockers and first-registered heart rhythm in out-of-hospital cardiac arrest: real-world data from population-based cohorts across two European countries.

AIMS: Conflicting results have been reported regarding the effect of beta-blockers on first-registered heart rhythm in out-of-hospital cardiac arrest (OHCA). We aimed to establish whether the use of beta-blockers influences first-registered rhythm in OHCA. METHODS AND RESULTS: We included patients with OHCA of presumed cardiac cause from two large independent OHCA-registries from Denmark and the Netherlands. Beta-blocker use was defined as exposure to either non-selective beta-blockers, ß1-selective beta-blockers, or α-ß-dual-receptor blockers within 90 days prior to OHCA. We calculated odds ratios (ORs) for the association of beta-blockers with first-registered heart rhythm using multivariable logistic regression. We identified 23 834 OHCA-patients in Denmark and 1584 in the Netherlands: 7022 (29.5%) and 519 (32.8%) were treated with beta-blockers, respectively. Use of non-selective beta-blockers, but not ß1-selective blockers, was more often associated with non-shockable rhythm than no use of beta-blockers [Denmark: OR 1.93, 95% confidence interval (CI) 1.48-2.52; the Netherlands: OR 2.52, 95% CI 1.15-5.49]. Non-selective beta-blocker use was associated with higher proportion of pulseless electrical activity (PEA) than of shockable rhythm (OR 2.38, 95% CI 1.01-5.65); the association with asystole was of similar magnitude, although not statistically significant compared with shockable rhythm (OR 2.34, 95% CI 0.89-6.18; data on PEA and asystole were only available in the Netherlands). Use of α-ß-dual-receptor blockers was significantly associated with non-shockable rhythm in Denmark (OR 1.21; 95% CI 1.03-1.42) and not significantly in the Netherlands (OR 1.37; 95% CI 0.61-3.07). CONCLUSION: Non-selective beta-blockers, but not ß1-selective beta-blockers, are associated with non-shockable rhythm in OHCA.