Sudden cardiac death in low- and middle-income countries

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

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

Types and Outcomes of Arrhythmias in a Cardiac Care Unit in Western Kenya: A Prospective Study

Background

Sustained arrhythmias are frequently encountered in cardiac care units (CCU), but their types and outcomes in Africa are unknown. Studies from high-income countries suggest arrhythmias are associated with worse outcomes.

Objectives

To determine the types and proportion of cardiac arrhythmias among patients admitted to the CCU at Moi Teaching and Referral Hospital (MTRH), and to compare 30-day outcomes between patients with and without arrhythmias at the time of CCU admission.

Methods

We conducted a prospective study of a cohort of all patients admitted to MTRH-CCU between March and December 2021. They were stratified on the presence or absence of arrhythmia at the time of CCU admission, irrespective of whether it was the primary indication for CCU care or not. Clinical characteristics were collected using a structured questionnaire. Participants were followed up for 30 days. The primary outcome of interest was 30-day all-cause mortality. Secondary outcomes were 30-day all-cause readmission and length of hospital stay. The 30-day outcomes were compared between the patients with and without arrhythmia, with a p value < 0.05 being considered statistically significant.

Results

We enrolled 160 participants. The median age was 46 years (IQR 31, 68), and 95 (59.4%) were female. Seventy (43.8%) had a diagnosis of arrhythmia at admission, of whom 62 (88.6%) had supraventricular tachyarrhythmias, five (7.1%) had ventricular tachyarrhythmias, and three (4.3%) had bradyarrhythmia. Atrial fibrillation was the most common supraventricular tachyarrhythmia (82.3%). There was no statistically significant difference in the primary outcome of 30-day mortality between those who had arrhythmia at admission versus those without: 32.9% versus 30.0%, respectively (p = 0.64).

Conclusion

Supraventricular tachyarrhythmias were common in critically hospitalized cardiac patients in Western Kenya, with atrial fibrillation being the most common. Thirty-day all-cause mortality did not differ significantly between the group admitted with a diagnosis of arrhythmia and those without.

Cardiac Arrest as a Public Health Issue

Sudden cardiac arrest has a large public health impact, especially, because its incidence continues to increase across the globe. Data for low-to-middle income countries is incomplete. CPR training and automatic external defibrillator availability are important points for focusing future efforts.

Sudden cardiac death in the adolescent population: a narrative review

Background

Death from unexpected circulatory arrest within 60 min of onset of symptom is known as sudden cardiac death (SCD). In spite of the advancement in treatment and prevention strategies, SCD remains the most common cause of death worldwide especially in the young.

Main body

This review focuses on highlighting how different cardiovascular diseases contribute to SCD. We discuss the clinical symptoms that the patient experience prior to sudden cardiac arrest and the treatment strategies including pharmacological and surgical treatment.

Conclusions

We conclude that since there are many causes of SCD and very few treatment options, prevention strategies, early detection, and resuscitation of those at greatest risk is important.

Neglected Tropical Diseases and Sudden Cardiac Death: The NET-Heart Project

Sudden cardiac death (SCD) is responsible for approximately 6% of global mortality and 25% of cardiovascular (CV) deaths. SCD has been traditionally linked to coronary artery disease, valvular heart disease, cardiomyopathies, and genetic arrhythmia disorders. However, advancements in care for these diseases have not translated to a proportional reduction in SCD. This suggests an important role of underrecognized contributing pathologies. Neglected tropical diseases (NTDs) are a group of illnesses prevalent in tropical and sub-tropical regions which have been understudied partially due to their high prevalence in marginalized populations. The relationship between SCD and Chagas disease has been well-established, though emerging literature suggests that other NTDs with CV involvement may lead to fatal arrhythmias. Additionally, specific therapies for a subset of NTDs put patients at increased risk of malignant arrhythmias and other cardiac complications. This review aims to summarize the association between a group of selected NTDs and SCD.

Hyperglycemia Identification Using ECG in Deep Learning Era

A growing number of smart wearable biosensors are operating in the medical IoT environment and those that capture physiological signals have received special attention. Electrocardiogram (ECG) is one of the physiological signals used in the cardiovascular and medical fields that has encouraged researchers to discover new non-invasive methods to diagnose hyperglycemia as a personal variable. Over the years, researchers have proposed different techniques to detect hyperglycemia using ECG. In this paper, we propose a novel deep learning architecture that can identify hyperglycemia using heartbeats from ECG signals. In addition, we introduce a new fiducial feature extraction technique that improves the performance of the deep learning classifier. We evaluate the proposed method with ECG data from 1119 different subjects to assess the efficiency of hyperglycemia detection of the proposed work. The result indicates that the proposed algorithm is effective in detecting hyperglycemia with a 94.53% area under the curve (AUC), 87.57% sensitivity, and 85.04% specificity. That performance represents an relative improvement of 53% versus the best model found in the literature. The high sensitivity and specificity achieved by the 10-layer deep neural network proposed in this work provide an excellent indication that ECG possesses intrinsic information that can indicate the level of blood glucose concentration.

A Systematic Review of the Spectrum of Cardiac Arrhythmias in Sub-Saharan Africa

Major structural cardiovascular diseases are associated with cardiac arrhythmias, but their full spectrum remains unknown in sub-Saharan Africa (SSA), which we addressed in this systematic review. Atrial fibrillation/atrial flutter (AF/AFL) prevalence is 16-22% in heart failure, 10-28% in rheumatic heart disease, 3-7% in cardiology admissions, but <1% in the general population. Use of oral anticoagulation is heterogenous (9-79%) across SSA. The epidemiology of sudden cardiac arrest/death is less characterized in SSA. Cardiopulmonary resuscitation is challenging, owing to low awareness and lack of equipment for life-support. About 18% of SSA countries have no cardiac implantable electronic devices services, leaving hundreds of millions of people without any access to treatment for advanced bradyarrhythmias, and implant rates are more than 200-fold lower than in the western world. Management of tachyarrhythmias is largely non-invasive (about 80% AF/AFL via rate-controlled strategy only), as electrophysiological study and catheter ablation centers are almost non-existent in most countries.

Highlights

- Atrial fibrillation/flutter prevalence is 16-22% in heart failure, 10-28% in rheumatic heart disease, 3-7% in cardiology admissions, and <1% in the general population in sub-Saharan Africa (SSA).- Rates of oral anticoagulation use for CHA2DS2VASC score ≥2 are very diverse (9-79%) across SSA countries.- Data on sudden cardiac arrest are scant in SSA with low cardiopulmonary resuscitation awareness.- Low rates of cardiac implantable electronic devices insertions and rarity of invasive arrhythmia treatment centers are seen in SSA, relative to the high-income countries.

Cardiac arrest and sudden cardiac death registries: a systematic review of global coverage

Background

Sudden cardiac death (SCD) is a major global health problem, accounting for up to 20% of deaths in Western societies. Clinical quality registries have been shown in a range of disease conditions to improve clinical management, reduce variation in care and improve outcomes.

Aim

To identify existing cardiac arrest (CA) and SCD registries, characterising global coverage and methods of data capture and validation.

Methods

Biomedical and public search engines were searched with the terms ‘registry cardio*’; ‘sudden cardiac death registry’ and ‘cardiac arrest registry’. Registries were categorised as either CA, SCD registries or ‘other’ according to prespecified criteria. SCD registry coordinators were contacted for contemporaneous data regarding registry details.

Results

Our search strategy identified 49 CA registries, 15 SCD registries and 9 other registries (ie, epistries). Population coverage of contemporary CA and SCD registries is highly variable with registries densely concentrated in North America and Western Europe. Existing SCD registries (n=15) cover a variety of age ranges and subpopulations, with some enrolling surviving patients (n=8) and family members (n=5). Genetic data are collected by nine registries, with the majority of these (n=7) offering indefinite storage in a biorepository.

Conclusions

Many CA registries exist globally, although with inequitable population coverage. Comprehensive multisource surveillance SCD registries are fewer in number and more challenging to design and maintain. Challenges identified include maximising case identification and case verification.

Trial registration number

CRD42019118910.

Arrhythmia care in Africa

Data on cardiovascular disease, including arrhythmias, in Africa is limited. However, the burden of cardiovascular disease appears to be on the rise. Recent global data suggests an increase in atrial fibrillation rates despite declining rates of rheumatic heart disease. Atrial fibrillation is also associated with increased mortality in Africa. Current management with medical therapy is sub-optimal and ablation procedures, inaccessible. Atrial fibrillation is also an independent risk factor for death in patients with rheumatic heart disease. Sudden cardiac deaths from ventricular arrhythmias are under-recognized and inadequately treated with very high rates out of hospital cardiac arrest due to poor education of the general public on cardiopulmonary resuscitation skills and lack of essential healthcare infrastructure. Use of cardiac devices such as implantable defibrillators and pacemakers is low with significant regional variations and is almost non-existent in sub-Saharan Africa. There is a great unmet need for arrhythmia diagnosis and management in Africa. Governments and healthcare stakeholders need to include cardiovascular disease as a healthcare priority given the rising burden of disease and associated mortality.

Amiodarone versus other pharmacological interventions for prevention of sudden cardiac death

BACKGROUND

Sudden cardiac death (SCD) is one of the main causes of cardiac death. There are two main strategies to prevent it: managing cardiovascular risk factors and reducing the risk of ventricular arrhythmias. Implantable cardiac defibrillators (ICDs) constitute the standard therapy for both primary and secondary prevention; however, they are not widely available in settings with limited resources. The antiarrhythmic amiodarone has been proposed as an alternative to ICD.

OBJECTIVES

To evaluate the effectiveness of amiodarone for primary or secondary prevention in SCD compared with placebo or no intervention or any other antiarrhythmic drugs in participants at high risk (primary prevention) or who have recovered from a cardiac arrest or a syncope due to Ventricular Tachycardia/Ventricular Fibrillation, or VT/VF (secondary prevention).

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE (OVID), EMBASE (OVID), CINAHL (EBSCO) and LILACS on 26 March 2015. We reviewed reference lists of included studies and selected reviews on the topic, contacted authors of included studies, screened relevant meetings and searched in registers for ongoing trials. We applied no language restrictions.

SELECTION CRITERIA

Randomised and quasi-randomised trials assessing the efficacy of amiodarone versus placebo, no intervention, or other antiarrhythmics in adults. For primary prevention we considered participants at high risk for SCD. For secondary prevention we considered participants recovered from cardiac arrest or syncope due to ventricular arrhythmias.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed the trials for inclusion and extracted relevant data. We contacted trial authors for missing data. We performed meta-analyses using a random-effects model. We calculated risk ratios (RR) for dichotomous outcomes with 95% confidence intervals (CIs). Three studies included more than one comparison.

MAIN RESULTS

We included 24 studies (9,997 participants). Seventeen studies evaluated amiodarone for primary prevention and six for secondary prevention. Only three studies used an ICD concomitantly with amiodarone for the comparison (all of them for secondary prevention).For primary prevention, amiodarone compared to placebo or no intervention (17 studies, 8383 participants) reduced SCD (RR 0.76; 95% CI 0.66 to 0.88), cardiac mortality (RR 0.86; 95% CI 0.77 to 0.96) and all-cause mortality (RR 0.88; 95% CI 0.78 to 1.00). The quality of the evidence was low.Compared to other antiarrhythmics (three studies, 540 participants), amiodarone reduced SCD (RR 0.44; 95% CI 0.19 to 1.00), cardiac mortality (RR 0.41; 95% CI 0.20 to 0.86) and all-cause mortality (RR 0.37; 95% CI 0.18 to 0.76). The quality of the evidence was moderate.For secondary prevention, amiodarone compared to placebo or no intervention (two studies, 440 participants) appeared to increase the risk of SCD (RR 4.32; 95% CI 0.87 to 21.49) and all-cause mortality (RR 3.05; 1.33 to 7.01). However, the quality of the evidence was very low. Compared to other antiarrhythmics (four studies, 839 participants) amiodarone appeared to increase the risk of SCD (RR 1.40; 95% CI 0.56 to 3.52; very low quality of evidence), but there was no effect in all-cause mortality (RR 1.03; 95% CI 0.75 to 1.42; low quality evidence).Amiodarone was associated with an increase in pulmonary and thyroid adverse events.

AUTHORS' CONCLUSIONS

There is low to moderate quality evidence that amiodarone reduces SCD, cardiac and all-cause mortality when compared to placebo or no intervention for primary prevention, and its effects are superior to other antiarrhythmics.It is uncertain if amiodarone reduces or increases SCD and mortality for secondary prevention because the quality of the evidence was very low.

Delta opioid receptor agonist BW373U86 attenuates post-resuscitation brain injury in a rat model of asphyxial cardiac arrest

OBJECTIVE

The aim of this study was to investigate whether the DOR agonist BW373U86 conferred neuroprotection following ACA when given after resuscitation and to determine the long-term effects of chronic BW373U86 treatment on ACA-elicited brain injury.

METHODS

Animals were divided into acute and chronic treatment groups. Each group consisted of four sub-groups, including Sham, ACA, BW373U86 (BW373U86+ACA), and Naltrindole groups (Naltrindole and BW373U86+ACA). The DOR antagonist Naltrindole was used to confirm the possible receptor-dependent effects of BW373U86. ACA was induced by 8min of asphyxiation followed by resuscitation. All drugs were administered either immediately after the restoration of spontaneous circulation (ROSC) in acute-treatment groups or over 6 consecutive days in chronic-treatment groups. Alterations of cAMP response element-binding protein (CREB) and phosphorylated CREB (pCREB) were analyzed by western blot and immunohistochemistry. Neurological functions were assessed by neurological deficit score (NDS) and Morris Water Maze performance. Neurodegeneration was monitored by immunofluorescence and Nissl staining.

RESULTS

ACA induced massive neuron loss and serious neurological function deficits. BW373U86 significantly reduced both of these negative effects and increased CREB and pCREB expression in the hippocampus; these effects were reversed with acute Naltrindole treatment. The protective effects of BW373U86 persisted until 28d post-ROSC with chronic treatment, but these effects were not reversed by Naltrindole.

CONCLUSIONS

BW373U86 attenuates global cerebral ischemic injury induced by ACA through both DOR-dependent and DOR-independent mechanisms. CREB might be an important molecule in mediating these neuroprotective effects.