Atrial fibrillation in Sub-Saharan Africa: epidemiology, unmet needs, and treatment options

Outcome of tailored therapy in rheumatic heart disease with persistent atrial fibrillation (RHD-AF)

INTRODUCTION

Rheumatic heart disease with persistent atrial fibrillation (RHD-AF) is associated with increased morbidity. However, there is no standardized approach for the maintenance of sinus rhythm (SR) in them. We aimed to determine the utility of a stepwise approach to achieve SR in RHD-AF.

METHODS

Consecutive patients with RHD-AF from July 2021 to August 2023 formed the study cohort. The stepwise approach included pharmacological rhythm control and/or electrical cardioversion (Central illustration). In patients with recurrence, additional options included AF ablation or pace and ablate strategy with conduction system pacing or biventricular pacing. Clinical improvement, NT-proBNP, 6-Minute Walk Test (6MWT), heart failure (HF) hospitalizations, and thromboembolic complications were documented during follow-up.

RESULTS

Eighty-three patients with RHD-AF (mean age 56.13 ± 9.51 years, women 72.28%) were included. Utilizing this approach, 43 (51.81%) achieved and maintained SR during the study period of 11.04 ± 7.14 months. These patients had improved functional class, lower NT-proBNP, better distance covered for 6MWT, and reduced HF hospitalizations. The duration of AF was shorter in patients who achieved SR, compared to those who remained in AF (3.15 ± 1.29 vs 6.93 ± 5.23, p = 0.041). Thirty-five percent (29) maintained SR after a single cardioversion over the study period. Only one underwent AF ablation. Of the 24 who underwent pace and ablate strategy, atrial lead was implanted in 22 (hybrid approach), and 50% of these achieved and maintained SR. Among these 24, none had HF hospitalizations, but patients who maintained SR had further improvement in clinical and functional parameters.

CONCLUSIONS

RHD-AF patients who could achieve SR with a stepwise approach, had better clinical outcomes and lower HF hospitalizations.

Simple Criteria, Yet the Dearth Utilization-Antithrombotic Management Practice among Atrial Fibrillation Patients at Hawassa University Comprehensive Specialized Hospital, Hawassa, Sidama, Ethiopia

Background

Atrial fibrillation (AF) is associated with significant mortality and morbidity from stroke and thromboembolism. Despite the availability of effective oral anticoagulation medication, AF patients remain at a high risk of stroke if not treated properly. The purpose of this study was to evaluate antithrombotic therapy practices in patients with AF in the adult cardiac clinic at Hawassa University Comprehensive Specialized Hospital (HUCSH).

Methods

It was a retrospective document review study. Total charts of 119 patients who had follow-up at the adult cardiac clinic with a history of documented AF from January 1 to December 30, 2018, were included. Indicators for antithrombotic therapy based on the congestive heart failure, hypertension, age ≥75 (doubled), diabetes, stroke (doubled), vascular disease, age 65 to 74, and sex category (female) (CHA2DS2-VASc) score were recorded. A p value of 0.05 was considered statistically significant. Data analysis was done using SPSS 23 software.

Results

In this study, about 55% of patients with AF were receiving the appropriate antithrombotic treatment. The patients were 48 ± 18.2 years old. Of these, 70% were women. The most frequent underlying cardiac etiology was chronic rheumatic valvular heart disease (50%), followed by cardiomyopathy (14%). In nonvalvular AF, the mean CHA2DS2VASc score was 4.0 ± 1.07. In valvular AF compared to nonvalvular AF, the need for appropriate antithrombotic therapy was substantially greater (p 0.0001). Only 8 (13.6%) of the warfarin-using patients had adequate anticoagulation.

Conclusion

The study's findings in regard to antithrombotic usage and maintenance of appropriate antithrombotics for stroke prevention in our patients revealed a discrepancy between recommendations and practice. Therefore, we demand that patients with AF who meet the criteria utilize antithrombotics properly to prevent stroke. Warfarin-taking patients' subpar optimum anticoagulation has to be addressed. Lastly, we advocate proper CHA2DS2-VASc score utilization for nonvalvular heart disease. A regular INR follow-up is also advised for patients who have started taking warfarin.

[Antithrombotiques oraux et pronostic après un an des patients atteints de fibrillation auriculaire dans un milieu à ressources limitées]

BACKGROUND

Atrial fibrillation is associated with increased risk of morbidity and mortality. There's limited data on the outcomes of atrial fibrillation patients in Africa. We aimed at evaluating the clinical outcomes and their associated factors in patients with atrial fibrillation on antithrombotic therapy in Douala.

METHODS

The Douala atrial fibrillation registry is a prospective, observational cohort study of patients with atrial fibrillation followed by cardiovascular specialists in 3 specialized care centres. From January to April 2018, all patients with electrocardiographic diagnosis of atrial fibrillation, aged 21 years or older, were included in the registry provided their consent. The composite endpoint of heart failure, stroke, major bleeding, hospitalisation and mortality as well as their individual occurrence were assessed at 12 months.

RESULTS

Of 113 participants that were included, 6(5.3%) were lost to follow-up. The mean age was 70 ± 12 years, with a female predominance (68%). After a mean follow-up time of 12.2 ± 0.7 months, 51 patients (47.7%) had at least one outcome. Hospitalisation, all-cause mortality, heart failure, stroke and major bleeding rates were 33.3%, 16.8%, 15.2%, 4.8% and 2.9% respectively. There was no significant difference in the composite outcome and mortality according to the antithrombotic treatment. Previous heart failure [aHR = 3.07, 95% CI (1.48-6.36) p = 0.003], new onset atrial fibrillation [aHR= 4.00, 95% CI (0.96-8.19) p < 0.001] and paroxystic atrial fibrillation [aHR= 3.74, 95% CI (1.33-10.53) p = 0.013] were significant predictors of outcome.

CONCLUSION

Half of patients with atrial fibrillation in this registry developed an outcome after one year of follow-up, with heart failure, new onset and paroxystic atrial fibrillation being the main predicting factors. Diagnosing and managing atrial fibrillation in patients with heart disease should therefore be considered as a key priority.

The Budget Impact Analysis of Adopting Direct Oral Anticoagulants for Stroke Prevention in Nonvalvular Atrial Fibrillation Patients in Malawi

OBJECTIVES

This study aimed to estimate the budget impact of adopting direct oral anticoagulants (DOACs) for stroke prevention in patients with nonvalvular atrial fibrillation in Malawi after the inclusion of DOACs in the World Health Organization's essential medicine list.

METHODS

A model was developed in Microsoft Excel. An eligible population of 201 491 was adjusted with 0.05 % incidence rate and mortality rates yearly according to the treatments. The model estimated the implication of supplementing rivaroxaban or apixaban to the standard treatment mix (also the comparator), thus warfarin and aspirin. The current market share of 43% aspirin and 57% warfarin was adjusted proportionally with 10% DOAC uptake in the first year and 5% annually over the subsequent 4 years. Clinical events of stroke and major bleeding from the ROCKET-AF and ARISTOTLE trials were used because health outcome indicators affect resource utilization. The analysis was conducted solely from the Malawi Ministry of Health perspective and it considered direct costs over 5 years. The sensitivity analysis involved varying drug costs, population, and care costs from both public and private sectors.

RESULTS

The research suggests that despite potential savings of $6 644 141 to $6 930 812 in stroke care because of fewer stroke events, the total Ministry of Health healthcare budget (approximately $260 400 000) may increase by between $42 488 342 to $101 633 644 in 5 years because drug acquisition costs are greater than savings.

CONCLUSIONS

With a fixed budget and current DOACs prices, Malawi can consider using DOACs in patients at the highest risk while waiting for cheaper generic versions.

Heart failure with reduced ejection fraction and atrial fibrillation: a Sub-Saharan African perspective

Cardiovascular diseases are a well-established cause of death in high-income countries. In the last 20 years, Sub-Saharan Africa (SSA) has seen one of the sharpest increases in cardiovascular disease-related mortality, superseding that of infectious diseases, including HIV/AIDS, in South Africa. This increase is evidenced by a growing burden of heart failure and atrial fibrillation (AF) risk factors. AF is a common comorbidity of heart failure with reduced ejection fraction (HFrEF), which predisposes to an increased risk of stroke, rehospitalizations, and mortality compared with patients in sinus rhythm. AF had the largest relative increase in cardiovascular disease burden between 1990 and 2010 in SSA and the second highest (106.4%) increase in disability-adjusted life-years (DALY) between 1990 and 2017. Over the last decade, significant advancements in the management of both HFrEF and AF have emerged. However, managing HFrEF/AF remains a clinical challenge for physicians, compounded by the suboptimal efficacy of guideline-mandated pharmacotherapy in this group of patients. There may be an essential role for racial differences and genetic influence on therapeutic outcomes of HFrEF/AF patients, further complicating our overall understanding of the disease and its pathophysiology. In SSA, the lack of accurate and up-to-date epidemiological data on this subgroup of patients presents a challenge in our quest to prevent and reduce adverse outcomes. This narrative review provides a contemporary overview of the epidemiology of HFrEF/AF in SSA. We highlight important differences in the demographic and aetiological profile and the management of this subpopulation, emphasizing what is currently known and, more importantly, what is still unknown about HFrEF/AF in SSA.

INVICTUS: Vitamin K antagonists remain the standard of care for rheumatic heart disease-associated atrial fibrillation

INTRODUCTION

Rheumatic heart disease (RHD) remains a major healthcare problem. Atrial fibrillation (AF) is the commonest sustained arrhythmia in RHD, leading to major complications and morbidity in a young population. Currently, anticoagulation with vitamin K antagonists (VKA) is the mainstay of therapy for the prevention of thromboembolic adverse events. However, effective use of VKA remains challenging, especially in developing countries, showing a need for alternatives. Novel oral anticoagulants (NOACs), including rivaroxaban, could form a safe and effective alternative to fulfil a major unmet need in RHD patients with AF. However, until recently, no data was available for the use rivaroxaban in patients with rheumatic heart disease associated AF. Study and Results: The INVICTUS trial was conducted to assess efficacy and safety of once-daily rivaroxaban compared with a dose-adjusted VKA for the prevention of cardiovascular events in patients with RHD-associated AF. A total of 4531 patients (age: 50.5 ± 14.6 years) were followed for 3.1 ± 1.2 years in which 560/2292 patients in the rivaroxaban group and 446/2273 in the VKA group had a primary-outcome adverse event. The restricted mean survival time was 1599 days in the rivaroxaban group and 1675 days in the VKA group (difference, -76 days; 95% confidence interval [CI], -121 to -31; P <0.001). A higher incidence of death occurred in the rivaroxaban group than in the VKA group (restricted mean survival time, 1608 days vs. 1680 days; difference, -72 days; 95% CI, -117 to -28). No significant between-group difference in the rate of major bleeding was noted.

LESSONS LEARNED

The INVICTUS trial shows that Rivaroxaban is inferior to Vitamin K-antagonists in patients with RHD associated AF as VKA therapy led to a lower rate of ischemic and lower mortality due to vascular causes, without significantly increasing the rate of major bleeding. The results support current guidelines, which recommend vitamin K antagonist therapy for the prevention of stroke in patients with RHD associated AF.

Electrophysiology practice in low- and middle-income countries: An updated review on access to care and health delivery

Concurrent with the epidemiological transition to cardiovascular diseases in low- and middle-income countries (LMICs), the burden of arrhythmias is increasing significantly. However, registries of electrophysiological disorders and their management in LMICs are limited. The advancement of telemedicine technology can play a distinctive role in providing accurate diagnoses in resource-limited settings. The estimated pacemaker implantation requirements (1 million per year) demand an alternate source of pacemakers, including reused permanent pacemakers and implantable cardioverter-defibrillators. In addition, the majority of supraventricular tachycardias and atrial fibrillation can be managed with radiofrequency ablation, which not only is cost-effective but is curative for most patients.

Prevalence and risk factors for atrial fibrillation in a semi-rural sub-Saharan African population: The hEart oF ethiopia: Focus on Atrial Fibrillation (TEFF-AF) Study

Background

There is a scarcity of reported data on the prevalence of atrial fibrillation (AF) in sub-Saharan Africa.

Objectives

To undertake AF screening in semi-rural Ethiopia.

Methods

The TEFF-AF (The hEart oF Ethiopia: Focus on Atrial Fibrillation) study conducted AF screening using a single-lead electrocardiogram device (KardiaMobile) on willing community participants at the Soddo Christian Hospital, Ethiopia. Participants' clinical parameters and medical history were obtained to characterize their risk factor profile, including calculation of CHARGE-AF (Cohorts for Heart and Aging Research in Genomic Epidemiology Atrial Fibrillation) score.

Results

A total of 3000 Ethiopians (median 31 [interquartile range 25-41] years of age; 65% men) were screened. The participants were generally well educated, from the local region and with a low burden of cardiovascular risk factors. A total of 50 participants had a CHARGE-AF score (5-year AF risk) of ≥2%. AF was detected in 13 (0.43%) individuals (median 50 [interquartile range 36-60] years of age; n = 7 men). The prevalence among participants over 40 years of age was 1% (n = 9 of 930). AF prevalence was higher for older age groups, with ≥70 years of age reaching 6.67% (n = 3 of 45). Population prevalence was estimated to be 234 (95% confidence interval 7-460) per 10,000 persons for ≥60 years of age. Four (31%) of the 13 participants with AF had a CHA₂DS₂-VASc (congestive heart failure, hypertension, age ≥75 years, diabetes mellitus, prior stroke or transient ischemic attack or thromboembolism, vascular disease, age 65-74 years, sex category) score of ≥2, and others likely had rheumatic valvular AF, but only 2 of the 13 participants with AF were on oral anticoagulation therapy.

Conclusion

In this semi-rural Ethiopian community of relatively younger participants, AF prevalence was found to be low but increased with increasing age. Mobile single-lead electrocardiogram technology can be used effectively for AF screening in low-resource settings.

[Atrial fibrillation in three cardiological reference centers in Dakar: Senegal data from the AFRICA register survey]

Introduction

atrial fibrillation (AF) is the most common cardiac rhythm disorder. Its prevalence is underestimated in Africa, hence the initiation of the Atrial Fibrillation Registry In Countries of Africa (AFRICA). The aim of our study was to describe, within the framework of the AFRICA registry, the epidemiological, clinical, paraclinical, therapeutic and evolutionary aspects of atrial fibrillation (AF) in Africa, particularly in Senegal.

Methods

we performed a cross-sectional, retrospective, multicentric study conducted from January 1^st to December 31^st 2017, in three referral cardiology wards in Senegal.

Results

one hundred and sixty-eight patients, with a mean age of 63 years, were selected, representing a hospital prevalence of 5.99%. There was a predominance of women with sex-ratio of 0.69. High blood pressure was the most frequent risk factor (24.4%). Heart failure was the most frequent circumstance of discovery (59.52%). AF was persistent in 52.24% and valvular AF accounted for 31% and was more frequent in young people (p= 0.005). Left ventricular systolic function was impaired in 55.7%, the left atrium was dilated in 70.83%. The strategy to reduce heart rate was the most used. Patients with CHA2DS2VASC ≥ 2 received anticoagulation with LMWH and oral relay maid mostly of VKA. The complications were dominated by heart failure (66.6%) and ischemic stroke cerebral (28%).

Conclusion

atrial fibrillation (AF) is the most frequent cardiac rhythm disorder. It is a major public health concern.

Rivaroxaban in Rheumatic Heart Disease-Associated Atrial Fibrillation

BACKGROUND

Testing of factor Xa inhibitors for the prevention of cardiovascular events in patients with rheumatic heart disease-associated atrial fibrillation has been limited.

METHODS

We enrolled patients with atrial fibrillation and echocardiographically documented rheumatic heart disease who had any of the following: a CHA2DS2VASc score of at least 2 (on a scale from 0 to 9, with higher scores indicating a higher risk of stroke), a mitral-valve area of no more than 2 cm2, left atrial spontaneous echo contrast, or left atrial thrombus. Patients were randomly assigned to receive standard doses of rivaroxaban or dose-adjusted vitamin K antagonist. The primary efficacy outcome was a composite of stroke, systemic embolism, myocardial infarction, or death from vascular (cardiac or noncardiac) or unknown causes. We hypothesized that rivaroxaban therapy would be noninferior to vitamin K antagonist therapy. The primary safety outcome was major bleeding according to the International Society of Thrombosis and Hemostasis.

RESULTS

Of 4565 enrolled patients, 4531 were included in the final analysis. The mean age of the patients was 50.5 years, and 72.3% were women. Permanent discontinuation of trial medication was more common with rivaroxaban than with vitamin K antagonist therapy at all visits. In the intention-to-treat analysis, 560 patients in the rivaroxaban group and 446 in the vitamin K antagonist group had a primary-outcome event. Survival curves were nonproportional. The restricted mean survival time was 1599 days in the rivaroxaban group and 1675 days in the vitamin K antagonist group (difference, -76 days; 95% confidence interval [CI], -121 to -31; P<0.001). A higher incidence of death occurred in the rivaroxaban group than in the vitamin K antagonist group (restricted mean survival time, 1608 days vs. 1680 days; difference, -72 days; 95% CI, -117 to -28). No significant between-group difference in the rate of major bleeding was noted.

CONCLUSIONS

Among patients with rheumatic heart disease-associated atrial fibrillation, vitamin K antagonist therapy led to a lower rate of a composite of cardiovascular events or death than rivaroxaban therapy, without a higher rate of bleeding. (Funded by Bayer; INVICTUS ClinicalTrials.gov number, NCT02832544.).

Warfarin Pharmacogenomics for Precision Medicine in Real-Life Clinical Practice in Southern Africa: Harnessing 73 Variants in 29 Pharmacogenes

Pharmacogenomics is universally relevant for worldwide modern therapeutics and yet needs further development in resource-limited countries. While there is an abundance of genetic association studies in controlled medical settings, there is a paucity of studies with a naturalistic design in real-life clinical practice in patients with comorbidities and under multiple drug treatment regimens. African patients are often burdened with communicable and noncommunicable comorbidities, yet the application of pharmacogenomics in African clinical settings remains limited. Using warfarin as a model, this study aims at minimizing gaps in precision/personalized medicine research in African clinical practice. We present, therefore, pharmacogenomic profiles of a cohort of 503 black Africans (n = 252) and Mixed Ancestry (n = 251) patients from Southern Africa, on warfarin and co-prescribed drugs in a naturalized noncontrolled environment. Seventy-three (n = 73) single nucleotide polymorphisms (SNPs) in 29 pharmacogenes were characterized using a combination of allelic discrimination, Sanger sequencing, restriction fragment length polymorphism, and Sequenom Mass Array. The common comorbidities were hypertension (43-46%), heart failure (39-45%), diabetes mellitus (18%), arrhythmia (25%), and HIV infection (15%). Accordingly, the most common co-prescribed drugs were antihypertensives, antiarrhythmic drugs, antidiabetics, and antiretroviral therapy. We observed marked variation in major pharmacogenes both at interethnic levels and within African subpopulations. The Mixed Ancestry group presented a profile of genetic variants reflecting their European, Asian, and African admixture. Precision medicine requires that African populations begin to capture their own pharmacogenetic SNPs as they cannot always infer with absolute certainty from Asian and European populations. In the current historical moment of the COVID-19 pandemic, we also underscore that the spectrum of drugs interacting with warfarin will likely increase, given the systemic and cardiovascular effects of COVID-19, and the anticipated influx of COVID-19 medicines in the near future. This observational clinical pharmacogenomics study of warfarin, together with past precision medicine research, collectively, lends strong support for incorporation of pharmacogenetic profiling in clinical settings in African patients for effective and safe administration of therapeutics.

The prevalence, management, and thirty-day outcomes of symptomatic atrial fibrillation in a Tanzanian emergency department

Introduction

Data describing atrial fibrillation (AF) care in emergency centres (ECs) in sub-Saharan Africa is lacking. We sought to describe the prevalence and outcomes of AF in a Tanzanian EC.

Methods

In a prospective, observational study, adults presenting with chest pain or shortness of breath to a Tanzanian EC were enrolled from January through October 2019. Participants underwent electrocardiogram testing which were reviewed by two independent physician judges to determine presence of AF. Participants were asked about their medical history and medication use at enrollment, and a follow-up questionnaire was administered via telephone thirty days later to assess mortality, interim stroke, and medication use.

Results

Of 681 enrolled patients, 53 (7.8%) had AF. The mean age of participants with AF was 68.1, with a standard deviation (sd) of 21.1 years, and 23 of the 53 (43.4%) being male. On presentation, none of the participants found to have AF reported a previous history of AF. The median CHADS-VASC score among participants was 4 with an interquartile range (IQR) of 2-4. No participants were taking an anticoagulant at baseline. On index presentation, 49 (92.5%) participants with AF were hospitalised with 52 (98.1%) participants completing 30-day follow-up. 18 (34%) participants died, and 5 (9.6%) suffered a stroke. Of the surviving 31 participants with AF and a CHADS-VASC score ≥ 2, none were taking other anti-coagulants at 30 days. Compared to participants without AF, participants with AF were more likely to be hospitalised (OR 5.25, 95% CI 2.10-17.95, p < 0.001), more likely to die within thirty days (OR 1.93, 95% CI 1.03-3.50, p = 0.031), and more likely to suffer a stroke within thirty days (OR 5.91, 95% CI 1.76-17.28, p < 0.001).

Discussion

AF is common in a Tanzanian EC, with thirty-day mortality being high, but use of evidence-based therapies is rare. There is an opportunity to improve AF care and outcomes in Tanzania.

•

In a Tanzanian emergency centre, atrial fibrillation was common but patient awareness of their condition was low

•

Use of anticoagulants among patients with atrial fibrillation was rare both before and after hospital presentation

•

Following hospital presentation, thirty-day mortality and stroke rates among patients with atrial fibrillation were high

Profiling of warfarin pharmacokinetics-associated genetic variants: Black Africans portray unique genetic markers important for an African specific warfarin pharmacogenetics-dosing algorithm

BACKGROUND

Warfarin dose variability observed in patients is attributed to variation in genes involved in the warfarin metabolic pathway. Genetic variation in CYP2C9 and VKORC1 has been the traditional focus in evaluating warfarin dose variability, with little focus on other genes.

OBJECTIVE

We set out to evaluate 27 single nucleotide polymorphisms (SNPs) in the CYP2C cluster loci and 8 genes (VKORC1, ABCB1, CYP2C9, CYP2C19, CYP2C8, CYP1A2, CYP3A4, and CYP3A5) involved in pharmacokinetics of warfarin.

PATIENTS/METHODS

503 participants were recruited among black Africans and Mixed Ancestry population groups, from South Africa and Zimbabwe, and a blood sample taken for DNA. Clinical parameters were obtained from patient medical records, and these were correlated with genetic variation.

RESULTS

Among black Africans, the SNPs CYP2C rs12777823G>A, CYP2C9 c.449G>A (*8), CYP2C9 c.1003C>T (*11) and CYP2C8 c.805A>T (*2) were significantly associated with warfarin maintenance dose. Conversely, CYP2C9 c.430C>T (*2), CYP2C8 c.792C>G (*4) and VKORC1 g.-1639G>A were significantly associated with maintenance dose among the Mixed Ancestry. The presence of CYP2C8*2 and CYP3A5*6 alleles was associated with increased mean warfarin maintenance dose, whereas CYP2C9*8 allele was associated with reduced warfarin maintenance dose.

CONCLUSION

African populations present with a diversity of variants that are important in predicting pharmacogenetics-based warfarin dosing in addition to those reported in CYP2C9 and VKORC1. It is therefore important, to include African populations in pharmacogenomics studies to be able to identify all possible biomarkers that are potential predictors for drug response.

Racial and Ethnic Differences in the Management of Atrial Fibrillation

Atrial fibrillation (AF) is the most common clinical arrhythmia, and it results in adverse outcomes and increased healthcare costs. Racial and ethnic differences in AF management, although recognized, are poorly understood. This review summarizes racial differences in AF epidemiology, genetics, clinical presentation, and management. In addition, it highlights the underrepresentation of racial and ethnic populations in AF clinical trials, especially trials focused on stroke prevention. Specific strategies are proposed for future research and initiatives that have potential to eliminate racial and ethnic differences in the care of patients with AF. Addressing racial and ethnic disparities in healthcare access, enrollment in clinical trials, resource allocation, prevention, and management will likely narrow the gaps in the care and outcomes of racial and ethnic minorities suffering from AF.

The Diagnostic Yield of Routine Electrocardiography in Hypertension and Implications for Care in a Southwestern Nigerian Practice

BACKGROUND

Nigeria, like other developing nations, has an increasing burden of hypertension. Electrocardiography is an integral part of the diagnostic work-up for the newly diagnosed hypertensive subjects. The aim of this study was to determine the diagnostic yield of electrocardiography in hypertensive patients of a southwestern Nigerian hospital.

PATIENTS AND METHODS

This was a retrospective descriptive study of electrocardiographs of hypertensive patients over a six-year period. Electrographic variables of interest were cardiac rhythm and rate, left ventricular hypertrophy (LVH), left atrial enlargement (LAE), T wave abnormalities, cardiac axis, blocks, complexes, QT segment abnormalities, atrial fibrillation (AF)/flutter, supraventricular tachycardia and pre-excitation syndrome. The Pearson's chi square was used to test for differences across age groups (15-44yrs, 45-64yrs and >65yrs) and between male and female subjects with the significance level set at 5% (p< 0.05).

RESULTS

Hypertension was the indication for 40% of electrocardiographs completed and comprised of 3713 electrocardiograms (ECG) over a six-year period. The commonest abnormalities were left axis deviation (LAD) (32.2%), LVH (20.7%), rhythm abnormalities (16.7%) and LAE (14.5%). The diagnostic yield (presence of at least one electrographic abnormality) was 51% in 15-44 yrs age group, 64% in middle aged and 76.5% in the >65 yrs age group. While the male subjects in this study had a slightly increased likelihood of having an abnormal finding (odds ratio 1.18: 95% CI 1.02-1.35), the odds ratio for an abnormal ECG in subjects younger than 45 years was 0.48 (95% CI 0.41-0.57).

CONCLUSION

The diagnostic yield of electrocardiography in this study was considerable, although lowest in subjects younger than 45 years and increased with age. This may reflect an increased burden and earlier onset of hypertension and its complications. This should also engender prompt and aggressive management of hypertension, especially in the elderly in whom the cardiovascular complications from hypertension is most severe.

Epidemiological characteristics, management, and outcomes of atrial fibrillation in TUNISIA: Results from the National Tunisian Registry of Atrial Fibrillation (NATURE-AF)

BACKGROUND

Contemporary registries on atrial fibrillation (AF) are scare in North African countries.

HYPOTHESIS

In the context of the epidemiological transition, prevalence of valvular AF in Tunisia has decreased and the quality of management is still suboptimal.

METHODS

NATURE-AF is a prospective Tunisian registry, involving consecutive patients with AF from March 1, 2017 to May 31, 2017, with a one-year follow-up period. All the patients with an Electrocardiogram-documented AF, confirmed in the year prior to enrolment were eligible. The epidemiological characteristics and outcomes were described.

RESULTS

A total of 915 patients were included in this study, with a mean age of 64.3 ± 22 years and a male/female sex ratio of 0.93. Valvular AF was identified in 22.4% of the patients. The mean CHA₂ DS₂ VASC score in nonvalvular AF was 2.4 ± 1.6. Monotherapy with antiplatelet agents was prescribed for 13.8% of the patients. However, 21.7% of the subjects did not receive any antithrombotic agent. Oral anticoagulants were prescribed for half of the patients with a low embolic risk score. In 341 patients, the mean time in therapeutic range was 48.87 ± 28.69%. Amiodarone was the most common antiarrhythmic agent used (52.6%). During a 12-month follow-up period, 15 patients (1.64%) had thromboembolism, 53 patients (5.8%) had major hemorrhage, and 52 patients (5.7%) died.

CONCLUSIONS

NATURE-AF has provided systematic collection of contemporary data regarding the epidemiological and clinical characteristics as well as the management of AF by cardiologists in Tunisia. Valvular AF is still prevalent and the quality of anticoagulation was suboptimal.

Improving anticoagulation in sub-Saharan Africa: What are the challenges and how can we overcome them?

Patients in sub-Saharan Africa generally have poor anticoagulation control. We review the potential reasons for this poor control, as well as the potential solutions. Challenges include the affordability and centralisation of anticoagulation care, problems with access to medicines and international normalised ratio monitoring, the lack of locally validated standardized dosing protocols, and low levels of anticoagulation knowledge among healthcare workers and patients. Increasing numbers of patients will need anticoagulation in the future because of the increasing burden of noncommunicable disease in the region. We propose that locally developed "warfarin care bundles" which address multiple anticoagulation challenges in combination may be the most appropriate solution in this setting currently.

Very Low Prevalence and Incidence of Atrial Fibrillation among Bolivian Forager-Farmers

Background

Atrial fibrillation is the most common arrhythmia in post-industrialized populations. Older age, hypertension, obesity, chronic inflammation, and diabetes are significant atrial fibrillation risk factors, suggesting that modern urban environments may promote atrial fibrillation.

Objective

Here we assess atrial fibrillation prevalence and incidence among tropical horticulturalists of the Bolivian Amazon with high levels of physical activity, a lean diet, and minimal coronary atherosclerosis, but also high infectious disease burden and associated inflammation.

Methods

Between 2005-2019, 1314 Tsimane aged 40-94 years (52% female) and 534 Moseten Amerindians aged 40-89 years (50% female) underwent resting 12-lead electrocardiograms to assess atrial fibrillation prevalence. For atrial fibrillation incidence assessment, 1059 (81% of original sample) Tsimane and 310 Moseten (58%) underwent additional ECGs (mean time to follow up 7.0, 1.8 years, respectively).

Findings

Only one (male) of 1314 Tsimane (0.076%) and one (male) of 534 Moseten (0.187%) demonstrated atrial fibrillation at baseline. There was one new (female) Tsimane case in 7395 risk years for the 1059 participants with >1 ECG (incidence rate = 0.14 per 1,000 risk years). No new cases were detected among Moseten, based on 542 risk years.

Conclusion

Tsimane and Moseten show the lowest levels of atrial fibrillation ever reported, 1/20 to ~1/6 of rates in high-income countries. These findings provide additional evidence that a subsistence lifestyle with high levels of physical activity, and a diet low in processed carbohydrates and fat is cardioprotective, despite frequent infection-induced inflammation. Findings suggest that atrial fibrillation is a modifiable lifestyle disease rather than an inevitable feature of cardiovascular aging.

Pragmatic Recommendations for the Management of Anticoagulation and Venous Thrombotic Disease for Hospitalized Patients with COVID-19 in Low- and Middle-Income Countries

New studies of COVID–19 are constantly updating best practices in clinical care. Often, it is impractical to apply recommendations based on high-income country investigations to resource limited settings in low- and middle-income countries (LMICs). We present a set of pragmatic recommendations for the management of anticoagulation and thrombotic disease for hospitalized patients with COVID-19 in LMICs. In the absence of contraindications, we recommend prophylactic anticoagulation with either low molecular weight heparin (LMWH) or unfractionated heparin (UFH) for all hospitalized COVID-19 patients in LMICs. If available, we recommend LMWH over UFH for venous thromboembolism (VTE) prophylaxis to minimize risk to healthcare workers. We recommend against the use of aspirin for VTE prophylaxis in hospitalized COVID-19 and non–COVID-19 patients in LMICs. Because of limited evidence, we suggest against the use of “enhanced” or “intermediate” prophylaxis in COVID-19 patients in LMICs. Based on current available evidence, we recommend against the initiation of empiric therapeutic anticoagulation without clinical suspicion for VTE. If contraindications exist to chemical prophylaxis, we recommend mechanical prophylaxis with intermittent pneumatic compression (IPC) devices or graduated compression stockings (GCS) for hospitalized COVID-19 patients in LMICs. In LMICs, we recommend initiating therapeutic anticoagulation for hospitalized COVID-19 patients, in accordance with local clinical practice guidelines, if there is high clinical suspicion for VTE, even in the absence of testing. If available, we recommend LMWH over UFH or Direct oral anticoagulants for treatment of VTE in LMICs to minimize risk to healthcare workers. In LMIC settings where continuous intravenous UFH or LMWH are unavailable or not feasible to use, we recommend fixed dose heparin, adjusted to body weight, in hospitalized COVID-19 patients with high clinical suspicion of VTE. We suggest D-dimer measurement, if available and affordable, at the time of admission for risk stratification, or when clinical suspicion for VTE is high. For hospitalized COVID-19 patients in LMICs, based on current available evidence, we make no recommendation on the use of serial D-dimer monitoring for the initiation of therapeutic anticoagulation. For hospitalized COVID-19 patients in LMICs receiving intravenous therapeutic UFH, we recommend serial monitoring of partial thromboplastin time or anti-factor Xa level, based on local laboratory capabilities. For hospitalized COVID-19 patients in LMICs receiving LMWH, we suggest against serial monitoring of anti-factor Xa level. We suggest serial monitoring of platelet counts in patients receiving therapeutic anticoagulation for VTE, to assess risk of bleeding or development of heparin induced thrombocytopenia.

Epidemiology of Atrial Fibrillation: Geographic/Ecological Risk Factors, Age, Sex, Genetics

Atrial fibrillation is the most common arrhythmia globally. The global prevalence of atrial fibrillation is positively correlated with the sociodemographic index of different regions. Advancing age, male sex, and Caucasian race are risk factors; female sex is correlated with higher atrial fibrillation mortality worldwide likely owing to thromboembolic risk. African American ethnicity is associated with lower atrial fibrillation risk, same as Asian and Hispanic/Latino ethnicities compared with Caucasians. Atrial fibrillation may be heritable, and more than 100 genetic loci have been identified. A polygenic risk score and clinical risk factors are feasible and effective in risk stratification of incident disease.

Appropriate use of anti-thrombotic therapy in patients with atrial fibrillation at single-center experience, Northwest Ethiopia

BACKGROUND

Atrial fibrillation (AF) is the commonest clinically significant ECG-evidenced sustained cardiac arrhythmia in clinical practice. Disability and mortality attributed to AF is high in low-income regions like sub-Saharan Africa. The risk of stroke/TIA in patients with AF can be significantly reduced with anti-thrombotic therapy. Despite the existing evidence of its benefit, significant percentages of AF patients eligible for anti-thrombotic therapy are undertreated in the region.

METHODS

A hospital-based cross-sectional study was conducted to determine the appropriate use of anti-thrombotic therapy in patients with AF between December 1, 2018 and September 30, 2019 at Cardiac Clinic, University of Gondar hospital, Northwest Ethiopia. Consecutive sampling method was used to recruit 210 study subjects. Patients were interviewed to obtain socio-demographic data. Relevant medical history and laboratory parameters were obtained from patients' records. Diagnosis of atrial fibrillation was based on detection of irregular arterial pulse and presence of 'f' waves on 12-lead ECG tracing. Clinical evaluation, echocardiography, chest X-ray and blood chemistry were used to diagnose underlying causes of AF. Data was entered into EPI Info version 4.4.1 and analyzed using SPSS version 20. Bi-variate and multi-variate logistic regression analyses were used to identify associated factors with appropriate use of anti-thrombotic therapy in patients with atrial fibrillation. P-values < 0.05 were used to declare significant association.

RESULTS

A total of 210 patients were included in the study. The mean age of patients was 51.29 ± 17.2 years. Two-thirds (145/210) of participants were females. Seventy-four (35%) had valvular AF, while 136/210 (65%) had non-valvular AF. Sixty-six percent (139/210) of study subjects were appropriately treated with anti-thrombotic therapy. Appropriately treated subjects in valvular AF group and non-valvular AF group were 58/74 (78%) and 81/136 (60%) respectively. On multi-variate analysis, 'can afford for regular INR monitoring' (AOR = 2.60 95% CI: 1.10-6.10, P = 0.001) was significantly associated with appropriate use of anti-thrombotic therapy.

CONCLUSION

Sixty-six percent of AF patients eligible for anti-thrombotic therapy were appropriately treated. Intervention program to access 'regular INR monitoring' should be practiced to escalate utilization rate of anti-thrombotic therapy (warfarin) in eligible AF patients.

Moving towards ideal and appropriate models of anticoagulation management service

It is now known that thrombotic disorders such as venous thromboembolism, ischemic stroke, and myocardial infarction contribute significantly to global morbidity and mortality. Anticoagulation service must respond to this new development. Warfarin has continued to provide the backbone for anticoagulation service for decades but with considerable drawbacks. The introduction of nonVitamin K oral anticoagulants (NOACs) has created new challenges. This article seeks to discuss how the establishment of appropriate models of anticoagulation could contain the draw backs of the old anticoagulants and improve on the compliance, availability, affordability, and accessibility of newer anticoagulants. Successful anticoagulation has always been defined by a scientific balancing of the risk of thrombosis and the complication of hemorrhage. To be able to maintain such optimal anticoagulation requires rational drug prescription (physician factor), institutelization of monitoring of therapy (anticoagulation clinic factor) as well as active participation of patients receiving therapy (patient factor). New models of service can be created out of this triad in a bid to replace the old routine medical care model. New models of anticoagulation service should include appropriately trained professionals such as Physicians, Pharmacists, Clinical Pharmacologists, Nurses, and Laboratory Scientists who are knowledgeable in diagnostic, management, and monitoring of anticoagulation. The different models of anticoagulation service discussed in this article clearly demonstrate the need for restructuring of this life saving service particularly in the era of NOAC. Newer models of care that should provide safe, efficacious, and cost-effective services are needed.

Meta-Analysis of the Incidence, Prevalence, and Correlates of Atrial Fibrillation in Rheumatic Heart Disease

Objective:

To estimate the incidence, prevalence, and correlates of atrial fibrillation (AF) in a global population with rheumatic heart disease (RHD).

Methods:

Bibliographic databases were searched to identify all published studies providing data on AF in patients with RHD. Random-effects meta-analysis method was used to pool estimates.

Results:

Eighty-three studies were included, reporting data from 75,637 participants with RHD in 42 countries. The global prevalence of AF in RHD was 32.8% (range: 4.3%–79.9%). It was higher in severe valvular disease (30.8% vs 20.7%, p = 0.009), in severe mitral valve disease compared to severe aortic disease (30.4% vs 6.3%, p = 0.038). The global cumulative incidence of AF in patients with RHD was 4.8%, 11.4%, 13.2%, and 30.8% at 1, 2, 5, and 10 years of follow-up, respectively. From comparison between patients with and without AF, AF was associated with increased age (mean difference [MD]: 9.5 years; 95% CI: 7.8–1.3), advanced heart failure (odds ratio [OR]: 4.4; 95% CI 2.1–9.3), tricuspid valve involvement (OR: 4.0; 95% CI: 3.0–5.3), history of thromboembolism (OR: 6.2; 95% CI: 3.4–11.4), highly sensitive C-reactive protein (MD: 5.5 mg/dL; 95% CI: 1.2–9.8), systolic pulmonary arterial pressure (MD: 3.6 mmHg; 95% CI: 0.8–6.3), right atrium pressure (MD: 1.5 mmHg; 95% CI: 1.0–2.0), and left atrium diameter (MD: 8.1 mm; 95% CI: 5.5–10.7).

Conclusions:

About one-third of patients with RHD have AF, with an incidence which almost triples every five years after diagnosis. Factors associated with AF include age, advanced heart failure, thromboembolism, and few cardiac hemodynamics parameters.

The Genetics of Warfarin Dose-Response Variability in Africans: An Expert Perspective on Past, Present, and Future

Coumarins such as warfarin are prescribed for prevention and treatment of thromboembolic disorders. Warfarin remains the most widely prescribed and an anticoagulant of choice in Africa. Warfarin use is, however, limited by interindividual variability in pharmacokinetics and a narrow therapeutic index. The difference in patients' pharmacodynamic responses to warfarin has been attributed to genetic variation in warfarin metabolism and molecular targets (e.g., CYP2C9 and VKORC1) and host-environment interactions. This expert review offers a synthesis of human genetics studies in Africans with respect to pharmacogenetics-informed warfarin dosing. We identify areas that need future research attention or could benefit from harnessing existing pharmacogenetics knowledge toward rational and optimal therapeutics with warfarin in African patients. A literature search was conducted until January 2019. A total of 343 articles were retrieved from nine African countries: Botswana, Ethiopia, Egypt, Ghana, Kenya, South Africa, Sudan, Tanzania, and Mozambique. We found 19 studies on genetics of warfarin treatment specifically among Africans. Genes examined included CYP2C9, VKORC1, CYP4F2, APOE, CALU, GGCX, and EPHX1. CYP2C9*2 and *3 alleles were highly frequent among Egyptians, while rare in other African populations. CYP2C9*5, *8, *9, and *11, and VKORC1 Asp36Tyr genetic variants explained warfarin variability in Africans better, compared to CYP2C9*2 and *3. In Africa, there is limited pharmacogenetics data on warfarin. Therefore, future research and funding commitments should be prioritized to ensure safe and effective use of warfarin in Africa. Lessons learned in Africa from the science of pharmacogenetics would inform rational therapeutics in hematology, cardiology, and surgical specialties worldwide.

Cardiac arrhythmias in low- and middle-income countries

Many low- and middle-income countries (LMICs) are undergoing an epidemiological transition. With an improvement in socioeconomic conditions and an aging population, cardiovascular diseases (CVDs), like cardiac arrhythmias, are expected to increase in these countries. However, there are limited studies on the epidemiology and management of cardiac arrhythmias in LMICs. This review will highlight the unique challenges and opportunities that these countries face when managing cardiac arrhythmias.

A review of the epidemiology of atrial fibrillation in sub-Saharan Africa

This systematic review summarizes the data on the prevalence, risk factors, complications, and management of atrial fibrillation (AF) in sub-Saharan Africa (SSA). Bibliographic databases were searched from inception to 31 May 2019, to identify all published studies providing data on AF in populations living in SSA. A total of 72 studies were included. The community-based prevalence of AF was 4.3% and 0.7% in individuals aged ≥40 years and aged ≥70 years, respectively. The prevalence of AF ranged between 6.7% and 34.8% in patients with ischemic stroke, between 9.5% and 46.8% in those with rheumatic heart disease (RHD), between 5% and 31.5% in patients with dilated cardiomyopathy. The main risk factors for AF were hypertension, affecting at least one-third of patients with AF, and valvular heart disease (12.3%-44.4%) and cardiomyopathy (~20%). Complications of AF included heart failure in about two thirds and stroke in 10% to 15% of cases. The use of anticoagulation for stroke prevention was suboptimal. Rate control was the most frequent therapeutic strategy, used in approximately 65% to 95% of AF patients, with approximately 80% of them achieving rate control. The management of AF was associated with exorbitant cost. In conclusion, AF seems to have a higher prevalence in the general population than previously thought and is mostly associated with hypertension, cardiomyopathy, and RHD in SSA. It is associated with a high incidence of heart failure and stroke. The management of AF is suboptimal in SSA, especially with a low uptake of oral anticoagulation.

Epidemiology and long-term prognosis of atrial fibrillation in rural African patients

BACKGROUND

Few studies have addressed the pattern of atrial fibrillation (AF) in rural Africa. The purpose of the study was to assess the epidemiology and long-term prognosis of AF in rural African patients in the Regional Hospital Center (RHC) of Tenkodogo, Burkina Faso.

RESULTS

Overall, 107 of 1805 cardiac cases presented with AF (prevalence of 5.9%). Six patients were excluded. Mean age was 66.56 ± 14.92 years, and 53.47% were female. Hypertension was the most prevalent cardiovascular risk factor (59.41%). Congestive heart failure (HF) was reported in 85.15% of the study patients at presentation. Most of the study population presented with severe underlying heart disease (93.1%), and hypertensive heart disease was the most prevalent with 45.54% of the cases. The mean CHA₂DS₂VASc score in patients with non-valvular heart disease (n = 91) was 3.33 ± 1.25 (extremes 1-6) while the risk of bleeding was low (HAS-BLED score ≤ 1) in 82 patients (81.2%). Oral anticoagulation was prescribed in few cases (5.26%). During a follow-up period of 74.43 ± 23.94 weeks, acute HF and stroke occurred in respectively 43 and 6 patients. Forty-one patients (40.59%) died. The overall survival rate was 69% at 6-month and 59.4% at 1-year follow-up. Patients with idiopathic dilated cardiomyopathy were at higher risk of death than other patients (log-rank test = 11.88, p < 0.001) over time.

CONCLUSION

AF is not rare in rural African patients and is associated with an increased long-term risk of HF, stroke, and mortality.

Pattern of stroke in a rural Kenyan hospital

Background

The pattern of stroke in rural population differs from that in urban ones. Although there are many studies on this condition in sub-Saharan Africa, few studies about stroke pattern in a Kenyan rural area exist.. This study therefore aims at describing the characteristics of stroke in a rural Kenyan hospital.

Patients and Methods

The study was conducted on 227 consecutive patients admitted with a World Health Organization (WHO) diagnosis of stroke in Kangundo Hospital, a level IV facility in Machakos, Eastern Kenya, between April 2015 and September 2016. The sub-type and anatomical distribution of stroke as well as the age, gender of the patients were recorded prospectively. Diagnosis was made through physical neurological examination and confirmed by Computerized Tomography (CT) scan imaging. Only those with complete bio-data, past medical and social history, clinical and physical findings of the patients and imaging results were included. The data were entered into a pre-formatted questionnaire, analysed for means, standard deviations and frequencies, and are presented in tables and bar charts.

Results

Out of 3200 medical admissions, 227 (7.09%) had a confirmed diagnosis of stroke. Ischaemic stroke was more common (67.4%) than haemorrhagic stroke (32.6%). It affected mainly the anterior circulation, especially the middle cerebral artery (39%). The mean age of patients was 68.8 years, (Range 32–96). It was more common in females (62%) than in males (38%). Hypertension was the most common (74%) risk factor followed by alcohol abuse (63%), tobacco smoking (48%) and diabetes mellitus (42%).

Conclusion

Ischaemic stroke was the more common major cause of morbidity in the rural hospital studied in Kenya. It occurred most commonly among elderly females, with the most frequent comorbidities being hypertension. In addition, modifiable lifestyle factors like alcohol abuse and cigarette smoking contributed to the prevalence; hence we recommend the control of blood pressure and glucose as well as lifestyle modification to reduce the scourge in our studied population.

Prevalence and risk factors for atrial fibrillation and its anticoagulant requirement in adults aged ≥40 in Jimma Town, Southwest Ethiopia: A community based cross-sectional study

BACKGROUND

There is no information on the prevalence and incidence of atrial fibrillation in Ethiopia. We aimed to investigate the prevalence, risk factors and anticoagulant requirements of atrial fibrillation in an elderly Jimma population.

METHODS

In a community-based cross-sectional study in 634 adult (≥40 years) Jimma population, we performed cardiovascular health examinations including a 12-lead electrocardiogram to estimate AF prevalence. A standardized questionnaire was used to collect information on medical history, lifestyle and use of medications. Stroke risk stratification was done using CHA2DS2-VASc score. We used logistic regressions to determine the potential risk factors of AF.

RESULTS

The overall prevalence of AF was 4.3%. AF was associated with sex, current smoking, hypertension and BMI. Nineteen out of twenty seven participants with AF were in need of anticoagulation to prevent risk of stroke.

CONCLUSION

The prevalence of AF is high and common risk factors were sex, current smoking, hypertension, and higher BMI in this cohort. More than two-third of study participants with AF were at higher need of oral anticoagulants.

Atrial fibrillation among adults with heart failure in sub-Saharan Africa - prevalence, incidence and all-cause mortality: a systematic review and meta-analysis protocol

INTRODUCTION

Heart failure (HF) remains a major non-communicable disease in sub-Saharan Africa (SSA) associated with high rates of readmission, mortality and loss of economic productivity as it affects mostly young and economically active adults. Atrial fibrillation (AFib) is a major determinant of mortality among patients with HF in SSA. Meanwhile, the use of anti-arrhythmic medications in the region remains unacceptably low. This review aims to evaluate the prevalence and incidence of AFib in adult patients with HF in SSA, and the all-cause mortality rate among patients with HF and AFib.

METHODS AND ANALYSIS

The Preferred Reporting Items for Systematic Reviews and Meta-Analyses for Protocols 2015 statement was used to prepare this protocol. All eligible studies from database inception to December, 31 2018 in MEDLINE, Embase, Google Scholar, Web of science and Africa-specific databases (AFROLIB, African Index Medicus and African Journals Online) will be included without language restrictions. The process of study screening, selection, data extraction and assessment of risk of bias will be conducted independently by two reviewers. Disagreements will be arbitrated by a third reviewer. Study-specific estimates will be pooled using random-effect meta-analysis and summary measures obtained will be presented in forest plots. The χ2 test on Cochrane's Q and the I2 statistics will be used to assess and quantify heterogeneity, respectively. The Egger's test and funnel plots will be used to assess publication bias.

ETHICS AND DISSEMINATION

Since our review will be based on already published data, an ethical approval is not required. The findings of this review will be presented in conferences and peer-reviewed journals and shared on social media such as Researchgate, Facebook, WhatsApp and Twitter.

PROSPERO REGISTRATION NUMBER

CRD42018087564.

Warfarin Dose and CYP2C Gene Cluster: An African Ancestral-Specific Variant Is a Strong Predictor of Dose in Black South African Patients

Warfarin is a widely prescribed anticoagulant with a narrow therapeutic index. The rs12777823G>A single-nucleotide polymorphism (SNP) in the CYP2C gene cluster has been shown to influence optimal warfarin doses in African Americans. We report here effects of rs12777823G>A SNP on warfarin dose requirements in two South African population groups, black Africans (BA) and mixed ancestry (MA). A total of 425 participants on warfarin treatment were enrolled in the study. The age group of the studied population ranged between 44 and 66 years, with 69% females enrolled. Genetic characterization of the rs12777823G>A was done using the TaqMan SNP genotyping assay. To further compare effects of rs12777823G>A to those of other SNPs, VKORC1 g.-1639G>A and 4 SNPs in CYP2C9 gene (i.e., CYP2C9 c.430C>T, c.1075A>C, c.449G>A, and c.1003C>T) were analyzed. The rs12777823A variant allele frequencies were 0.28 and 0.25 in the BA and MA, respectively. The rs12777823A/A genotype was associated with significantly (p = 0.002) reduced mean warfarin dosage (27 ± 5.3 mg/week) compared with the G/G genotype (45 ± 16.1 mg/week) among BA, but not among the MA. The rs12777823G>A is located in a nongenomic region, suggesting that this SNP might be in linkage disequilibrium with another, likely causal SNP that is present in BA only. Given ongoing worldwide efforts to identify clinically relevant human genetic variation impacting on optimal warfarin dose selection, the African ancestry-specific genetic variant in the CYP2C cluster and others warrant further research and consideration in development of future warfarin dosing algorithms for precision medicine guidelines.

Design and Rationale of the National Tunisian Registry of Atrial Fibrillation: Protocol for a Prospective, Multicenter Trial

Background

Atrial fibrillation (AF) is an important health problem in Tunisia. A significant change in the epidemiological pattern of heart disease has been seen in the last 3 decades; however, no large prospective multicenter trial reflecting national data has been published so far. Robust data on the contemporary epidemiological profile and management of AF patients in Tunisia are limited.

Objective

The aim of this study is to analyze, follow, and evaluate patients with AF in a large multicenter nationwide trial.

Methods

A total of 1800 consecutive patients with AF by electrocardiogram, reflecting all populations of all geographical regions of Tunisia, will be included in the study, with the objective of describing the epidemiological pattern of AF. Patients will be officially enrolled in the National Tunisian Registry of Atrial Fibrillation (NATURE-AF) only if an electrocardiogram diagnosis (12-lead, 24-hour Holter, or other electrocardiographic documentation) confirming AF is made. The qualifying episode of AF should have occurred within the last year, and patients do not need to be in AF at the time of enrollment. Patients will be followed for 1 year. Incidence of stroke or transient ischemic attack, thromboembolic events, and cardiovascular death will be recorded as the primary end point, and hemorrhagic accidents, measurement of international normalized ratio, and time in therapeutic range will be recorded as secondary end points.

Results

Results will be available at the end of the study; the demographic profile and general risk profile of Tunisian AF patients, frequency of anticoagulation, frequency of effective treatment, and risks of thromboembolism and bleeding will be evaluated according to the current guidelines. Major adverse events will be determined. NATURE-AF will be the largest registry for North African AF patients.

Conclusions

This study would add data and provide a valuable opportunity for real-world clinical epidemiology in North African AF patients with insights into the uptake of contemporary AF management in this developing region.

Trial Registration

ClinicalTrials.gov NCT03085576; https://clinicaltrials.gov/ct2/show/NCT03085576 (Archived by WebCite at http://www.webcitation.org/6zN2DN2QX)

Registered Report Identifier

RR1-10.2196/8523

Characteristics of patients with thromboembolic disorders on warfarin therapy in resource limited settings

Background

Warfarin is a drug with narrow therapeutic index used in the management of thromboembolic disorders. Several factors affect its plasma concentrations with a resultant risk of toxicity. We examined the database of patients on warfarin therapy in order to establish the factors that affect the stability of INR and correlated them to clinical outcomes in resource limited settings.

Methods

We analysed retrospective data of patients admitted to adult medical wards at Moi Teaching and Referral Hospital (MTRH) in 2015. Inclusion criteria were patients with thromboembolic and related disorders and on warfarin treatment. Derived data included demographics, indications for warfarin use, co-prescribed drugs, co-morbidities, INR measurements, duration of hospital stay and clinical outcomes. Descriptive statistics were used to summarize the data. Pearson’s correlation coefficient was used to assess relationships between duration of hospitalization and number of INR tests. Regression splines were used to capture INR trends during the follow up period. Data was analysed using R v. 3.3.1.

Results

A total of 310 patients had thromboembolic disorders, out of which 63 met the study criteria.

The median age was 48 years, while the mean number of INR measurements was once every four days. Majority of patients did not achieve stable INR values, with only two having consecutive INR values within therapeutic goal. Patients who died had high INR levels. The median duration of hospital stay was 9 days (IQR: 7.0, 16.5). There was a significant correlation between length of stay in hospital and the number of times that INR were measured (Corr = 0.667, p < 0.001). The two most common indications for warfarin were DVT (64.4%) and atrial fibrillation (24.7%). All the patients had one or more comorbid conditions except for 11 with DVT alone, with cardiovascular diseases and infections being the most frequent, and on concomitant medications, majority of which are known to interact with warfarin.

Conclusions

It was difficult to achieve stable INR under the prevailing conditions despite the frequent tests.

The potential factors that may have contributed to the fluctuations include drug-drug interactions, frequency of INR tests, comorbidities and the short duration of hospital stay.

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.

Point-of-care coagulation monitoring: first clinical experience using a paper-based lateral flow diagnostic device

Vitamin K antagonists such as warfarin are the most widely used class of oral anticoagulants. Due to a narrow therapeutic window, patients on warfarin require regular monitoring. Self-testing using point-of-care (POC) diagnostic devices is available, but cost makes this monitoring method beyond reach for many. The main objective of this research was to assess the clinical utility of a low-cost, paper-based lateral flow POC diagnostic device developed for anticoagulation monitoring without the need for a separate electronic reader. Custom-fabricated lateral flow assay (LFA) test strips comprised of a glass fiber sample pad, a nitrocellulose analytical membrane, a cellulose wicking pad, and a plastic backing card were assembled in a plastic cassette. Healthy volunteers and patients on warfarin therapy were recruited for this prospective study. For each participant, a whole blood sample was collected via fingerstick to determine: (1) international normalized ratio (INR) using the CoaguChek® XS coagulometer, (2) hematocrit by centrifugation, and (3) red blood cell (RBC) travel distance on the experimental LFA device after 240 s using digital image analysis. RBC travel distance measured on the LFA device using blood samples obtained from warfarin patients positively correlated with increasing INR value and the LFA device had the capability to statistically distinguish between healthy volunteer INR values and those for patients groups with INR ≥ 2.6. From these data, it is predicted that this low-cost, paper-based LFA device can have clinical utility for identifying anticoagulated patients taking vitamin K antagonists who are outside of the desired therapeutic efficacy window.

Cardiovascular disease in Africa: epidemiological profile and challenges

From a global perspective, the large and diverse African population is disproportionately affected by cardiovascular disease (CVD). The historical balance between communicable and noncommunicable pathways to CVD in different African regions is dependent on external factors over the life course and at a societal level. The future risk of noncommunicable forms of CVD (predominantly driven by increased rates of hypertension, smoking, and obesity) is a growing public health concern. The incidence of previously rare forms of CVD such as coronary artery disease will increase, in concert with historically prevalent forms of disease, such as rheumatic heart disease, that are yet to be optimally prevented or treated. The success of any strategies designed to reduce the evolving and increasing burden of CVD across the heterogeneous communities living on the African continent will be dependent upon accurate and up-to-date epidemiological data on the cardiovascular profile of every major populace and region. In this Review, we provide a contemporary picture of the epidemiology of CVD in Africa, highlight key regional discrepancies among populations, and emphasize what is currently known and, more importantly, what is still unknown about the CVD burden among the >1 billion people living on the continent.

Feasibility of Using Mobile ECG Recording Technology to Detect Atrial Fibrillation in Low-Resource Settings

BACKGROUND

Screening for atrial fibrillation (AF), a major risk factor for stroke that is on the rise in Africa, is becoming increasingly critical.

OBJECTIVES

This study sought to examine the feasibility of using mobile electrocardiogram (ECG) recording technology to detect AF.

METHODS

In this prospective observational study, we used a mobile ECG recorder to screen 50 African adults (66% women; mean age 54.3 ± 20.5 years) attending Kijabe Hospital (Kijabe, Kenya). Five hospital health providers involved in this study's data collection process also completed a self-administered survey to obtain information on their access to the Internet and mobile devices, both factors necessary to implement ECG mobile technology. Outcome measures included feasibility (completion of the study and recruitment of the patients on the planned study time frame) and the yield of the screening by the mobile ECG technology (ability to detect previously undiagnosed AF).

RESULTS

Patients were recruited in a 2-week period as planned; only 1 of the 51 patients approached refused to participate (98% acceptance rate). All of the 50 patients who agreed to participate completed the test and produced readable ECGs (100% study completion rate). ECG tracings of 4 of the 50 patients who completed the study showed AF (8% AF yield), and none had been previously diagnosed with AF. When asked about continuous access to Internet and personal mobile devices, almost all of the health care providers surveyed answered affirmatively.

CONCLUSIONS

Using mobile ECG technology in screening for AF in low-resource settings is feasible, and can detect a significant proportion of AF cases that will otherwise go undiagnosed. Further study is needed to examine the cost-effectiveness of this approach for detection of AF and its effect on reducing the risk of stroke in developing countries.

Prestroke treatment of stroke risk factors: A cross-sectional survey in central Nigeria

Background:

Stroke can be prevented with treatments targeted at hypertension, diabetes mellitus, hyperlipidemia and atrial fibrillation, but this is often hampered by under-diagnosis and under-treatment of those risk factors. The magnitude of this problem is not well-studied in sub-Saharan Africa.

Materials and Methods:

We conducted a cross-sectional survey of stroke patients at a tertiary hospital during January 2010 to July 2013 to determine patient awareness of a pre-existing stroke risk factor and prior use of anti-hypertensive, anti-diabetic, antiplatelet and lipid-lowering agents. We also investigated whether gender and school education influenced patient awareness and treatment of a stroke risk factor prior to stroke.

Results:

Three hundred and sixty nine stroke patients presented during the study period, of which 344 eligible subjects were studied. Mean age at presentation (±SD) was 55.8 ± 13.7 years, and was not different for men and women. Hypertension, hyperlipidemia, diabetes and atrial fibrillation were prevalent among 83.7%, 26.5%, 25.6% and 9.6% patients respectively. Awareness was high for pre-existing diabetes (81.8%) and hypertension (76.7%), but not for hyperlipidemia (26.4%) and atrial fibrillation (15.2%). Men were better educated than women (p = 0.002), and had better awareness for hyperlipidemia (37.3% versus 13.5%; p = 0.009). Men were also more likely to take drug treatments for a stroke risk factor, but the differences were significant.

Conclusions:

A high rate of under-diagnosis and under-treatment of hypertension, hyperlipidemia and atrial fibrillation contributes to the stroke burden in sub-Saharan Africa, especially among women. Public health measures including mass media campaigns could help reduce the burden of stroke.