Recent advances in the epidemiology, diagnosis and treatment of endomyocardial fibrosis in Africa

Left septal fascicular block: Evidence, causes, and diagnostic criteria

The existence of a tetrafascicular intraventricular conduction system is widely accepted by researchers. In this review, we have updated the criteria for left septal fascicular block (LSFB) and the differential diagnosis of prominent anterior QRS forces. More and more evidence points to the fact that the main cause of LSFB is critical proximal stenosis of the left anterior descending coronary artery before its first septal perforator branch. The most important characteristic of LSFB that has been incorporated in the corresponding diagnostic electrocardiographic criteria is its transient/intermittent nature mostly observed in clinical scenarios of acute (ie, acute coronary syndrome including vasospastic angina) or chronic (ie, exercise-induced ischemia) ischemic coronary artery disease. In addition, the phenomenon proved to be phase 4 bradycardia rate dependent and induced by early atrial extrastimulus. Finally, we believe that intermittent LSFB has the same clinical significance as "Wellens syndrome" and the "de Winter pattern" in the acute coronary syndrome scenario.

Genetic predisposition study of heart failure and its association with cardiomyopathy

Heart failure (HF) is a clinical condition distinguished by structural and functional defects in the myocardium, which genetic and environmental factors can induce. HF is caused by various genetic factors that are both heterogeneous and complex. The incidence of HF varies depending on the definition and area, but it is calculated to be between 1 and 2% in developed countries. There are several factors associated with the progression of HF, ranging from coronary artery disease to hypertension, of which observed the most common genetic cause to be cardiomyopathy. The main objective of this study is to investigate heart failure and its association with cardiomyopathy with their genetic variants. The selected novel genes that have been linked to human inherited cardiomyopathy play a critical role in the pathogenesis and progression of HF. Research sources collected from the human gene mutation and several databases revealed that numerous genes are linked to cardiomyopathy and thus explained the hereditary influence of such a condition. Our findings support the understanding of the genetics aspect of HF and will provide more accurate evidence of the role of changing disease accuracy. Furthermore, a better knowledge of the molecular pathophysiology of genetically caused HF could contribute to the emergence of personalized therapeutics in future.

Neglected cardiovascular diseases and their significance in the Global North

Due to increasing global migration, the spectrum of cardiovascular disease (CVD) is changing in developed countries. Up to 3% of migrants arriving in Europe have underlying CVD. Despite their high global prevalence, conditions such as rheumatic heart disease, Chagas disease, endomyocardial fibrosis, tuberculous pericarditis, peripartum cardiomyopathy, and pulmonary hypertension are often under-recognized, and, as a result, neglected in industrialized countries. Many of these conditions, and their causes, are often unfamiliar to the health-care providers in host countries. In this review, we summarize the epidemiology, etiology, clinical presentation, diagnostic work-up, and management of neglected CVDs that have an increasing prevalence in the Global North.

Endomyocardial fibrosis

Background

Endomyocardial fibrosis (EMF) is a neglected cardiovascular disease of poverty which carries a poor prognosis with no specific treatment affecting mainly children and young adults. Here, we report our 10-year experience in the therapeutic management and surgical treatment for EMF.

Methods

From February 2009 to 2019 March, 55 patients diagnosed with EMF from our cardiology unit underwent surgical repair at our department's pediatric surgical division. There were 35 male, and 20 female patients whose ages varied from 1 year 2 months to 12 years mean age 5.7 (±3.2). We designed the study aimed at assessing the cardio-structural abnormalities and coronary vascular changes faced with EMF patients using echocardiography, and coronary angiography with a detailed and thorough surgical examination of each case.

Results

Of the 55 operated patients, 1 had mild lesions, 26 had moderate lesions, and 28 had severe heart disease. All but one patient was in NYHA functional class III or IV at the time of surgery. All but one female patient with mild ventricular lesions and no valvular involvement had severe atrioventricular valve regurgitation with valves considered suitable for both replacements; 45 patients mean age 6.0 (±3.1) and repair nine patients mean age 3.8 (±2.9). The mean endocardial thickness was 3,000 (±1519) µm.

Conclusions

The echocardiographic changes corresponded well to the findings on surgery and histopathology. The coronary changes seen included a spectrum of fibrin deposition, medial sclerosis and degeneration, and the formation of plexiform lesions. Surgically evaluating the resected cardiac tissue might help improve disease management.

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.

Cardiovascular Diseases in Sub-Saharan Africa Compared to High-Income Countries: An Epidemiological Perspective

Non-communicable diseases (NCDs) are the second common cause of death in sub-Saharan Africa (SSA) accounting for about 35% of all deaths, after a composite of communicable, maternal, neonatal, and nutritional diseases. Despite prior perception of low NCDs mortality rates, current evidence suggests that SSA is now at the dawn of the epidemiological transition with contemporary double burden of disease from NCDs and communicable diseases. In SSA, cardiovascular diseases (CVDs) are the most frequent causes of NCDs deaths, responsible for approximately 13% of all deaths and 37% of all NCDs deaths. Although ischemic heart disease (IHD) has been identified as the leading cause of CVDs mortality in SSA followed by stroke and hypertensive heart disease from statistical models, real field data suggest IHD rates are still relatively low. The neglected endemic CVDs of SSA such as endomyocardial fibrosis and rheumatic heart disease as well as congenital heart diseases remain unconquered. While the underlying aetiology of heart failure among adults in high-income countries (HIC) is IHD, in SSA the leading causes are hypertensive heart disease, cardiomyopathy, rheumatic heart disease, and congenital heart diseases. Of concern is the tendency of CVDs to occur at younger ages in SSA populations, approximately two decades earlier compared to HIC. Obstacles hampering primary and secondary prevention of CVDs in SSA include insufficient health care systems and infrastructure, scarcity of cardiac professionals, skewed budget allocation and disproportionate prioritization away from NCDs, high cost of cardiac treatments and interventions coupled with rarity of health insurance systems. This review gives an overview of the descriptive epidemiology of CVDs in SSA, while contrasting with the HIC and highlighting impediments to their management and making recommendations.

Endomyocardial fibrosis in Sudan: clinical and echocardiographic features

Objective:

Endomyocardial fibrosis (EMF) is a rare disease and is often an underdiagnosed and forgotten cardiomyopathy. The objective of this study was to document the current frequency of EMF in Sudan by defining and selecting cases from patients attending the echocardiography laboratory. Additionally we aimed to create an EMF registry for Sudan.

Methods:

The study started in January 2007 and is on-going. All the patients attending our echocardiography clinics in four different hospitals in Khartoum, Sudan, were included. Transthoracic echocardiography was used as the main diagnostic and selection tool. The diagnosis of EMF was based on predefined criteria and definitions, and was further supported by additional clinical, ECG, laboratory and chest X-ray findings.

Results:

Out of 4 332 cases studied, 23 (0.5%) were found to have features of EMF. Females constituted 52% and the age range was 24 to 67 years. All patients presented with dyspnoea grades III–IV. Advanced heart failure with gross fluid overload was seen in 54% of cases and ascites was seen in 30%. EMF was biventricular in 53%, left ventricular in 29% and right ventricular in 18% of cases. Apical and ventricular wall fibrosis was found in all cases, followed by atrial enlargement, atrioventricular valve incompetence, ventricular cavity obliteration, restrictive flow pattern and pericardial effusion. Additional echocardiographic features are defined and discussed.

Conclusion:

Although a rare disease, cases of EMF can be identified in Sudan if a high index of suspicion is observed. New echocardiographic features of ventricular wall layering, endocardial fibrous shelf and endomyocardiopericarial fibrosis were identified and are discussed.

[Tropical endomyocardial fibrosis: Perspectives]

Tropical endomyocardial fibrosis (FET) is a leading cause of heart failure and the most common restrictive cardiomyopathy worldwide. Extensive fibrosis of the ventricular endocardium causing architectural distortion, impaired filling and valvular insufficiency define the disease. Confined to peculiar and limited geographical areas, the aetiology remains blurred and it carries a grim prognosis. The changing burden reported recently in some endemic areas and the refinement of diagnostic tools have emphasized alternative routes for understanding and treatment of the disease.

Tropical diseases of the myocardium: a review

Cardiovascular diseases are widely distributed throughout the world. Human parasitic infections are ubiquitous. Tropical parasites are increasingly recognized as causes of cardiovascular diseases. In this review, we address the most frequently reported parasites that directly infect the myocardium, including Trypanosoma cruzi, the protozoal causative agent of American trypanosomiasis (Chagas disease), and Taenia solium, the cestode causative agent of taeniasis and cysticercosis. We also discuss tropical endomyocardial fibrosis, trichinellosis and schistosomiasis. Health systems, attitudes, the perceptions of both patients and physicians as well as socioeconomic factors should all be explored and recognized as crucial factors for improving the control of cardiovascular diseases in the tropics. Clinicians throughout the world must remain aware of imported parasites as potential causes of cardiac diseases.

Tropical Endomyocardial Fibrosis: Natural History, Challenges, and Perspectives

Tropical endomyocardial fibrosis (EMF) is a neglected disease of poverty that afflicts rural populations in tropical low-income countries, with some certain high-prevalence areas. Tropical EMF is characterized by the deposition of fibrous tissue in the endomyocardium, leading to restrictive physiology. Since the first descriptions in Uganda in 1948, high-frequency areas for EMF have included Africa, Asia, and South America. Although there is no clear consensus on a unified hypothesis, it seems likely that dietary, environmental, and infectious factors may combine in a susceptible individual to give rise to an inflammatory process leading to endomyocardial damage and scar formation. The natural history of EMF includes an active phase with recurrent flare-ups of inflammation evolving to a chronic phase leading to restrictive heart failure. In the chronic phase, biventricular involvement is the most common presentation, followed by isolated right-sided heart disease. Marked ascites out of proportion to peripheral edema usually develops as a typical feature of EMF. EMF carries a very poor prognosis. In addition to medical management of heart failure, early open heart surgery (endocardectomy and valve repair/replacement) appears to improve outcomes to some extent; however, surgery is technically challenging and not available in most endemic areas. Increased awareness among health workers and policy makers is the need of the hour for the unhindered development of efficient preventive and therapeutic strategies.

Endomyocardial fibrosis: missing tricuspid valve and Fontan-like circulation

Endomyocardial fibrosis (EMF) is a progressive type of obliterative/restrictive cardiomyopathy characterized by fibrosis of the apical endomyocardium of the ventricles. Although the prognosis of EMF patients is poor in tropical regions, the exact clinical course and pathogenesis of patients with EMF are not known. Here, we report the rare case with EMF in the seventh decade, who showed the disappearance of papillary muscles, chordae tendineae, and part of the tricuspid valves due to massive right ventricular thrombus. Because of those unusual findings of the isolated RV involvement, we observed continuous forward pulmonary artery flow, as occurring in a Fontan circulation.

Contributions of risk factors and medical care to cardiovascular mortality trends

Ischaemic heart disease, stroke, and other cardiovascular diseases (CVDs) lead to 17.5 million deaths worldwide per year. Taking into account population ageing, CVD death rates are decreasing steadily both in regions with reliable trend data and globally. The declines in high-income countries and some Latin American countries have been ongoing for decades without slowing. These positive trends have broadly coincided with, and benefited from, declines in smoking and physiological risk factors, such as blood pressure and serum cholesterol levels. These declines have also coincided with, and benefited from, improvements in medical care, including primary prevention, diagnosis, and treatment of acute CVDs, as well as post-hospital care, especially in the past 40 years. These variables, however, explain neither why the decline began when it did, nor the similarities and differences in the start time and rate of the decline between countries and sexes. In Russia and some other former Soviet countries, changes in volume and patterns of alcohol consumption have caused sharp rises in CVD mortality since the early 1990s. An important challenge in reaching firm conclusions about the drivers of these remarkable international trends is the paucity of time-trend data on CVD incidence, risk factors throughout the life-course, and clinical care.

The right ventricle under pressure: evaluating the adaptive and maladaptive changes in the right ventricle in pulmonary arterial hypertension using echocardiography (2013 Grover Conference series)

The importance of the right ventricle (RV) in pulmonary arterial hypertension (PAH) has been gaining increased recognition. This has included a reconceptualization of the RV as part of an RV-pulmonary circulation interrelated unit and the observation that RV function is a major determinant of prognosis in PAH. Noninvasive imaging of RV size and function is critical to the longitudinal management of patients with PAH, and continued understanding of the pathophysiology of pulmonary vascular disease relies on the response of the RV to pulmonary vascular remodeling. Echocardiography, in particular the newer echocardiographic measurements and techniques, allows easy, readily accessible means to assess and follow RV size and function.

Right ventricular endomyocardial fibrosis (2013 Grover Conference series)

Endomyocardial fibrosis (EMF) is a restrictive cardiomyopathy of unknown origin, affecting predominantly the right side of the heart. Its highest prevalence is in poor regions of sub-Saharan Africa, where it is usually found in children and adolescents. In areas where it is endemic, EMF is a major cause of heart failure and premature death. EMF of the right ventricle has unique clinical, electrocardiographic, and echocardiographic signs. Several features of advanced disease are not fully understood, the most striking being the presence of severe ascites with little or no pedal edema. Echocardiography is the main diagnostic tool and supports management of the disease in most patients, as it allows assessment of the severity and extension of endocardial fibrosis, the quality of the right atrioventricular valve, and the presence of intracardiac thrombi. Pulmonary hypertension in the setting of right EMF is related to chronic thromboembolism, through the chronic thrombi present in the severely enlarged right atrium found in advanced disease. The management of right EMF is difficult. Treatment of symptomatic patients should be surgical. However, as the disease is usually detected in late stages, with severe and advanced lesions, surgery cannot be performed without a very high risk of death and complications. New surgical approaches addressing several components of the structural cardiac abnormalities have been attempted, with promising results. EMF remains one of the most neglected diseases worldwide, and research into its pathophysiological mechanisms will probably improve outcomes and alter the natural history of the disease. This requires improvement in the health systems in areas of endemicity as well as the design of international collaborative research projects.

A rare case of hypertrophic cardiomyopathy with subendocardial late gadolinium enhancement in an apical aneurysm with thrombus

The mechanisms responsible for the development of apical aneurysms in cases of hypertrophic cardiomyopathy (HCM) are currently unclear but likely involve multiple factors. Here, we present a case of HCM with marked subendocardial fibrosis involving the apical and proximal portions of the left ventricle. A 71-year-old man with left ventricular hypertrophy presented with signs and symptoms of heart failure. The presence of asymmetrical left ventricular hypertrophy and bilateral, thickened ventricular walls with an apical aneurysm on transthoracic echocardiography suggested a diagnosis of HCM with ventricular dysfunction. No intraventricular pressure gradients with obstruction were identified. Late gadolinium enhancement (LGE) with cardiac magnetic resonance imaging and endomyocardial biopsies showed subendocardial fibrosis involving the apical aneurysm and proximal portion. Whereas LGE in a transmural pattern is commonly observed in HCM apical aneurysms, subendocardial LGE, as noted in the present case, is a relatively rare occurrence. Thus, the present case may provide unique insights into the adverse remodeling process and formation of apical aneurysms in cases of HCM.

Distribution of late gadolinium enhancement in various types of cardiomyopathies: Significance in differential diagnosis, clinical features and prognosis

The recent development of cardiac magnetic resonance (CMR) techniques has allowed detailed analyses of cardiac function and tissue characterization with high spatial resolution. We review characteristic CMR features in ischemic and non-ischemic cardiomyopathies (ICM and NICM), especially in terms of the location and distribution of late gadolinium enhancement (LGE). CMR in ICM shows segmental wall motion abnormalities or wall thinning in a particular coronary arterial territory, and the subendocardial or transmural LGE. LGE in NICM generally does not correspond to any particular coronary artery distribution and is located mostly in the mid-wall to subepicardial layer. The analysis of LGE distribution is valuable to differentiate NICM with diffusely impaired systolic function, including dilated cardiomyopathy, end-stage hypertrophic cardiomyopathy (HCM), cardiac sarcoidosis, and myocarditis, and those with diffuse left ventricular (LV) hypertrophy including HCM, cardiac amyloidosis and Anderson-Fabry disease. A transient low signal intensity LGE in regions of severe LV dysfunction is a particular feature of stress cardiomyopathy. In arrhythmogenic right ventricular cardiomyopathy/dysplasia, an enhancement of right ventricular (RV) wall with functional and morphological changes of RV becomes apparent. Finally, the analyses of LGE distribution have potentials to predict cardiac outcomes and response to treatments.

DNA methylation in cardiac fibrosis: new advances and perspectives

Cardiac fibrosis is characterized by net accumulation of extracellular matrix (ECM) proteins in the cardiac interstitium, and contributes to both systolic and diastolic dysfunction in many cardiac pathophysiologic conditions. More specifically, cardiac fibroblasts are activated by a variety of pathological stimuli, thereby undergoing proliferation, differentiation to myofibroblasts, and production of various cytokines and ECM proteins. Thus, understanding the biological processes of cardiac fibroblasts will provide novel insights into the underlying mechanisms of cardiac fibrosis. DNA methylation is an important epigenetic mechanism, which often occurs in response to environmental stimuli and is crucial in regulating gene expression. The aberrant methylation of CpG island promoters of selected genes is the prominent epigenetic mechanism by which gene transcription can be effectively silenced. Aberrant hypermethylation of a few selected genes such as RASSF1A plays an important role in facilitating fibrotic fibroblast activation and in driving fibrosis. In this review we will discuss the mechanisms of DNA methylation and their implications for cardiac fibroblasts activation and fibrosis. Control of DNA methylation may serve as a new strategy for anti-fibrotic therapy.

Public health: Cardiovascular disease insights--something new out of Africa

Adverse trends in blood pressure, diabetes mellitus, and other cardiometabolic risk factors, together with population growth and ageing, are contributing to the burden of cardiovascular diseases in Africa. This increasing problem, coupled with inadequate access to effective interventions for prevention, diagnosis, and treatment, is creating major public-health challenges across the continent.