Isolated Left Ventricular Noncompaction in Sub-Saharan Africa: A Clinical and Echocardiographic Perspective

Clinical and cardiovascular magnetic resonance profile of cardiomyopathy patients from South Africa: Pilot of the IMHOTEP study

BACKGROUND

Cardiomyopathy is an important cause of heart failure, however, there is notable lack of data on causes and manifestations of cardiomyopathy in Africa.

AIMS

The African Cardiomyopathy and Myocarditis Registry Program (IMHOTEP) aims to address the knowledge gap on etiology, treatment, and outcomes of cardiomyopathy in sub-Saharan Africa.

METHODS AND RESULTS

We conducted a single-center pilot study to delineate the clinical and cardiovascular magnetic resonance (CMR) phenotypes of cardiomyopathy in South African patients. Assessment of the first 99 adult incident cases [mean age 36.8 ± 12.5 years; females 53.5%] enrolled in IMHOTEP showed that dilated cardiomyopathy (n = 77) was commonest, followed by hypertrophic (n = 13), restrictive (n = 5) and arrhythmogenic (n = 4) cardiomyopathies. A broad range of etiologies were encountered with secondary causes identified in 42% of patients. Onset of symptoms in the peripartum period was observed in 47% of women, and peripartum cardiomyopathy was diagnosed in 32.1% of women recruited. In addition to electrocardiography and echocardiography, CMR was performed in 67 cases and contributed diagnostically in a third of cases. Acute inflammation was rarely observed [2%] on CMR, however, late gadolinium enhancement (LGE) was noted in 92% of cases.

CONCLUSION

We report a diverse spectrum of causes of cardiomyopathy in the South African population, with secondary, potentially treatable, etiologies in a significant proportion of cases. CMR was useful in delineating specific phenotypes and etiologies, influencing clinical care. A higher-than-expected burden of LGE was observed in this young patient cohort - the implications of which are yet to be determined.

Myocardial Mechanics and Associated Valvular and Vascular Abnormalities in Left Ventricular Noncompaction Cardiomyopathy

Left ventricular (LV) non-compaction (LVNC) is a rare genetic cardiomyopathy due to abnormal intra-uterine arrest of compaction of the myocardial fibers during endomyocardial embryogenesis. Due to the partial or complete absence of LV compaction, the structure of the LV wall shows characteristic abnormalities, including a thin compacted epicardium and a thick non-compacted endocardium with prominent trabeculations and deep intertrabecular recesses. LVNC is frequently associated with chronic heart failure, life-threatening ventricular arrhythmias, and systemic embolic events. According to recent findings, in the presence of LVNC, dysfunctional LV proved to be associated with left atrial volumetric and functional abnormalities and consequential dilated and functionally impaired mitral annulus, partly explaining the higher prevalence of regurgitation. Although the non-compaction process morphologically affects only the LV, signs of remodeling of the right heart were also detected. Moreover, dilation and stiffening of the aorta were present. The aim of the present detailed review was to summarize findings regarding changes in cardiac mechanics, valvular abnormalities, and vascular remodeling detected in patients with LVNC.

Left ventricular noncompaction in Ibadan, Nigeria

BACKGROUND

There has been an increase in the reporting of cases of left ventricular noncompaction (LVNC) cardiomyopathy in medical literature due to advances in medical imaging. Patients with LVNC may be asymptomatic or may present with arrhythmias, heart failure, thromboembolism or sudden death. LVNC is typically diagnosed by echocardiography, although there are higher-resolution cardiac imaging techniques such as cardiac magnetic resonance imaging (MRI) to make the diagnosis. The objective of the study is to report on a series of 9 cases of LVNC cardiomyopathy seen at the University College Hospital, Ibadan. Cases of LVNC seen between September 1, 2015 and July 31, 2022 in our echocardiography service  is being reported.

RESULTS

There were a total of 6 men and 3 women. Mean age at presentation was 52.89 ± 15.02 years. The most common mode of presentation was heart failure (6 patients). Hypertension was the most common comorbidity (6 patients). Three patients had an ejection fraction of less than 40% and the mean ratio of noncompacted to compacted segment at end-systole was 2.80 ± 0.48. The most common areas of trabecular localization were the LV lateral wall and the apex. Beta blockers were highly useful in the management of the patients.

CONCLUSIONS

LVNC cardiomyopathy is not uncommon in our environment and a high index of suspicion is often required.

The Rare Condition of Left Ventricular Non-Compaction and Reverse Remodeling

Left ventricular non-compaction (LVNC) is a rare disease defined by morphological criteria, consisting of a two-layered ventricular wall, a thin compacted epicardial layer, and a thick hyper-trabeculated myocardium layer with deep recesses. Controversies still exist regarding whether it is a distinct cardiomyopathy (CM) or a morphological trait of different conditions. This review analyzes data from the literature regarding diagnosis, treatment, and prognosis in LVNC and the current knowledge regarding reverse remodeling in this form of CM. Furthermore, for clear exemplification, we report a case of a 41-year-old male who presented symptoms of heart failure (HF). LVNC CM was suspected at the time of transthoracic echocardiography and was subsequently confirmed upon cardiac magnetic resonance imaging. A favorable remodeling and clinical outcome were registered after including an angiotensin receptor neprilysin inhibitor in the HF treatment. LVNC remains a heterogenous CM, and although a favorable outcome is not commonly encountered, some patients respond well to therapy.

Left Ventricular Non-Compaction Spectrum in Adults and Children: From a Morphological Trait to a Structural Muscular Disease

Left ventricular non-compaction (LVNC) is an extremely heterogeneous disorder with a highly variable clinical presentation, morphologic appearance at imaging testing, and prognosis. It is still unclear whether LVNC should be classified as a separate cardiomyopathy or if it is a mere morphological trait shared by many phenotypically distinct cardiomyopathies. Moreover, the hypertrabeculated phenotype may be reversible in some cases, possibly reflecting the left ventricular physiological response of the cardiac muscle to chronic overload. The current diagnostic criteria have several limitations, leaving many patients in a grey area. Here, we review the available literature on LVNC in order to provide an overview of the current knowledge on this complex disorder.

A systematic review and meta-analysis of the prevalence of left ventricular non-compaction in adults

AIMS

To assess the reported prevalence of left ventricular non-compaction (LVNC) in different adult cohorts, taking in to consideration the role of diagnostic criteria and imaging modalities used.

METHODS AND RESULTS

A systematic review and meta-analysis of studies reporting LVNC prevalence in adults. Studies were sourced from Pre-Medline, Medline, and Embase and assessed for eligibility according to inclusion criteria. Eligible studies provided a prevalence of LVNC in adult populations (≥12 years). Studies were assessed, and data extracted by two independent reviewers. Fifty-nine eligible studies documenting LVNC in 67 unique cohorts were included. The majority of studies were assessed as moderate or high risk of bias. The pooled prevalence estimates for LVNC were consistently higher amongst cohorts diagnosed on cardiac magnetic resonance (CMR) imaging (14.79%, n = 26; I2 = 99.45%) compared with echocardiogram (1.28%, n = 36; I2 = 98.17%). This finding was unchanged when analysis was restricted to studies at low or moderate risk of bias. The prevalence of LVNC varied between disease and population representative cohorts. Athletic cohorts demonstrated high pooled prevalence estimates on echocardiogram (3.16%, n = 5; I2 = 97.37%) and CMR imaging (27.29%, n = 2).

CONCLUSION

Left ventricular non-compaction in adult populations is a poorly defined entity which likely encompasses both physiological adaptation and pathological disease. There is a higher prevalence with the introduction of newer imaging technologies, specifically CMR imaging, which identify LVNC changes more readily. The clinical significance of these findings remains unclear; however, there is significant potential for overdiagnosis, overtreatment, and unnecessary follow-up.

Neurological complications of cardiomyopathies

There is a multifaceted relationship between the cardiomyopathies and a wide spectrum of neurological disorders. Severe acute neurological events, such as a status epilepticus and aneurysmal subarachnoid hemorrhage, may result in an acute cardiomyopathy the likes of Takotsubo cardiomyopathy. Conversely, the cardiomyopathies may result in a wide array of neurological disorders. Diagnosis of a cardiomyopathy may have already been established at the time of the index neurological event, or the neurological event may have prompted subsequent cardiac investigations, which ultimately lead to the diagnosis of a cardiomyopathy. The cardiomyopathies belong to one of the many phenotypes of complex genetic diseases or syndromes, which may also involve the central or peripheral nervous systems. A number of exogenous agents or risk factors such as diphtheria, alcohol, and several viruses may result in secondary cardiomyopathies accompanied by several neurological manifestations. A variety of neuromuscular disorders, such as myotonic dystrophy or amyloidosis, may demonstrate cardiac involvement during their clinical course. Furthermore, a number of genetic cardiomyopathies phenotypically incorporate during their clinical evolution, a gamut of neurological manifestations, usually neuromuscular in nature. Likewise, neurological complications may be the result of diagnostic procedures or medications for the cardiomyopathies and vice versa. Neurological manifestations of the cardiomyopathies are broad and include, among others, transient ischemic attacks, ischemic strokes, intracranial hemorrhages, syncope, muscle weakness and atrophy, myotonia, cramps, ataxia, seizures, intellectual developmental disorder, cognitive impairment, dementia, oculomotor palsies, deafness, retinal involvement, and headaches.

Prevalence and significance of isolated left ventricular non-compaction phenotype in normal black Africans using echocardiography

Background

Several large, prospective screening studies of predominantly Caucasian patients have suggested that hypertrabeculation may not necessarily be pathologic unless there is concomitant left ventricular (LV) dysfunction, LV dilatation, history of arrhythmia, family history, or characteristic gene mutations. This conundrum may be magnified in blacks, in whom hypertrabeculation and LV hypertrophy is more common. We therefore investigated the frequency of hypertrabeculation/isolated LV noncompaction (ILVNC) phenotype in normal black Africans and evaluated LV function using sensitive measures of deformation and twist.

Methods

Two hundred and fifty-three volunteers were recruited and evaluated according to strict inclusion and exclusion criteria. Their mean age was 36.3 ± 12.2 years.

Results

Trabeculations were found in 12 (4.74%) participants. Three (1.2%) subjects had ≥ 4 LV trabeculations. The LV apex was the most common anatomical site for the location of trabeculations. Subjects with trabeculations were more likely to be males of a younger age, and had greater LV end-diastolic and end-systolic parameters and lateral e’. However, 0.8% of the population fulfilled the Stollberger criteria, and none fulfilled the Jenni, Milwaukee, or Baragwanath criteria. All subjects in this study had normal rotation patterns with no differences in rotational parameters or net twist.

Conclusions

Trabeculations may be found as a normal variant in black Africans. Assessing trabeculations alone may infer ILVNC; however, utilizing the more comprehensive ILVNC criteria enables differentiation of a possible LVNC phenotype. Normal individuals with hypertrabeculation have normal LV function and normal rotation patterns, with no differences in rotational parameters or net twist.

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.

Genetics of inherited cardiomyopathies in Africa

In sub-Saharan Africa (SSA), the burden of noncommunicable diseases (NCDs) is rising disproportionately in comparison to the rest of the world, affecting urban, semi-urban and rural dwellers alike. NCDs are predicted to surpass infections like human immunodeficiency virus, tuberculosis and malaria as the leading cause of mortality in SSA over the next decade. Heart failure (HF) is the dominant form of cardiovascular disease (CVD), and a leading cause of NCD in SSA. The main causes of HF in SSA are hypertension, cardiomyopathies, rheumatic heart disease, pericardial disease, and to a lesser extent, coronary heart disease. Of these, the cardiomyopathies deserve greater attention because of the relatively poor understanding of mechanisms of disease, poor outcomes and the disproportionate impact they have on young, economically active individuals. Morphofunctionally, cardiomyopathies are classified as dilated, hypertrophic, restrictive and arrhythmogenic; regardless of classification, at least half of these are inherited forms of CVD. In this review, we summarise all studies that have investigated the incidence of cardiomyopathy across Africa, with a focus on the inherited cardiomyopathies. We also review data on the molecular genetic underpinnings of cardiomyopathy in Africa, where there is a striking lack of studies reporting on the genetics of cardiomyopathy. We highlight the impact that genetic testing, through candidate gene screening, association studies and next generation sequencing technologies such as whole exome sequencing and targeted resequencing has had on the understanding of cardiomyopathy in Africa. Finally, we emphasise the need for future studies to fill large gaps in our knowledge in relation to the genetics of inherited cardiomyopathies in Africa.

Left ventricular twist before and after haemodialysis: an analysis using speckle-tracking echocardiography

Background

The most commonly used parameter of cardiac function in the chronic kidney disease (CKD) patient is ejection fraction (EF), using transthoracic echocardiography (TTE). EF is a highly load-dependent measurement, which varies considerably in CKD patients undergoing haemodialysis. The aim of this pilot study was to evaluate a novel measure of myocardial function, left ventricular twist, which is defined as the ‘wringing action of the heart’, using speckletracking echocardiography in CKD patients before and after haemodialysis.

Methods

Twenty-six patients were recruited from the Chris Hani Baragwanath Hospital haemodialysis unit. TTE was performed according to a detailed standardised protocol before and after a single haemodialysis session. Echocardiography was also performed on 26 age- and gendermatched healthy subjects.

Results

The mean age of the control versus CKD group was 44 ± 11.4 and 43.4 ± 12.2 years, respectively; 46% were male. Apical rotation was diminished in CKD patients compared to controls (4.83 ± 2.3 vs 6.31 ± 1.6 °; p = 0.01) despite no difference in EF (61.7 ± 6.2 vs 58.8 ± 13; p = 0.68). There were no differences in the components of twist: apical rotation, basal rotation and net twist before and after dialysis, despite an increase in EF (58.8 ± 13.7 vs 61.2 ± 13.6; p = 0.02) following dialysis.

Conclusion

Unlike EF, the components of twist are relatively independent of changes in haemodynamic load seen during dialysis. The decrease in apical rotation may represent an early marker of cardiac pathology in the late-stage CKD patient.

Cardiomyopathies Due to Left Ventricular Noncompaction, Mitochondrial and Storage Diseases, and Inborn Errors of Metabolism

The normal function of the human myocardium requires the proper generation and utilization of energy and relies on a series of complex metabolic processes to achieve this normal function. When metabolic processes fail to work properly or effectively, heart muscle dysfunction can occur with or without accompanying functional abnormalities of other organ systems, particularly skeletal muscle. These metabolic derangements can result in structural, functional, and infiltrative deficiencies of the heart muscle. Mitochondrial and enzyme defects predominate as disease-related etiologies. In this review, left ventricular noncompaction cardiomyopathy, which is often caused by mutations in sarcomere and cytoskeletal proteins and is also associated with metabolic abnormalities, is discussed. In addition, cardiomyopathies resulting from mitochondrial dysfunction, metabolic abnormalities, storage diseases, and inborn errors of metabolism are described.

Non-compaction of left ventricular myocardium in sub-Saharan African adults

BACKGROUND

Non-compaction of the left ventricle (NCLV) is an unclassified cardiomyopathy due to intrauterine arrest of compaction of the loose interwoven meshwork. Only a few studies involving sub-Saharan Africans insmall numbers have been published. The aim of our study was to determine the diagnostic, therapeutic and prognostic aspects as well as the clinical course of NCLV in a black African population.

METHODOLOGY

A multicentre retrospective study was carried out between November 2007 and June 2012 in two cardiology departments in Dakar. Patients who met the echocardiographic criteria for NCLV were included in the study.

RESULTS

35patients with the diagnosis of NCLV were evaluated in the study. Their mean age was 47±18.4 years. Heart failure was found in 77.1% of the patients. The most frequent electrocardiographic abnormalities were left ventricular hypertrophy (LVH) (46%) and sinus tachycardia (43%). Mean non-compaction/compaction ratio was 2.84±0.68 with preferential localization in the apex of the left ventricle. The main complications observed were cardiogenic shock (23.5%), pulmonary embolism (6.3%) and ventricular tachycardia (5.9%). Diuretics and ACE inhibitors were the medications most often prescribed. Age >60 years (p=0.04), male gender (p=0.03) and the occurrence of complications during follow-up (p=0.04) were noted to be predictors of poor prognosis.

CONCLUSION

Contrary to previous beliefs, NCLV may not be less common in black Africans than in other ethnic subgroups. Clinicians in Africa should be made aware of NCLV so that it can be diagnosed at earlier stages.

Left Ventricular Non-Compaction: A Cardiomyopathy With Acceptable Prognosis in Children

BACKGROUND

Data on children with left ventricular non-compaction (LVNC) is sparse. The purpose of this study was to evaluate its clinical profiles in a population of Chinese children.

METHODS

From January 2010 to March 2016, consecutive Chinese children (aged <18 years) with LVNC diagnosed by cardiovascular magnetic resonance (CMR) were prospectively recruited at Fuwai Hospital.

RESULTS

A total of 41 Chinese children (male: 28%; mean age: 14±4years) were included in this study. Left ventricular non-compaction was not detected in 13 (32%) patients at initial echocardiographic evaluation. Congenital heart disease (CHD) was found in 11 (27%) patients. Four (10%) patients had Wolff-Parkinson-White (WPW) syndrome. Mean left ventricular ejection fraction (LVEF) was 41±15%. Late gadolinium enhancement (LGE) was detected in eight (20%) subjects. During a mean follow-up of 2.9 years, four (9%) patients died or received heart transplantation. These patients had lower systolic blood pressure (91±10 vs. 108±14mmHg; p=0.02), diastolic blood pressure (57±7 vs. 68±8mmHg; p=0.007) and LVEF (19±7 vs. 44±12%; p=0.002) than the survivors. In addition, advanced heart failure (100% vs. 16%; p=0.002) and LGE (50% vs. 5%; p=0.04) were detected more in these subjects.

CONCLUSIONS

Left ventricular non-compaction is easily overlooked at echocardiographic assessment. Congenital heart disease and WPW syndrome were relatively common in LVNC children. The prognosis of children with LVNC seemed to be better than previous studies reported, and its long-term prognosis needs to be further investigated.

Evaluation and management of left ventricular noncompaction cardiomyopathy

Left ventricular (LV) noncompaction cardiomyopathy (LVNC) is a form of cardiomyopathy in which trabeculations fail to "compact" with the left ventricular endocardium during fetal cardiac development and is classically associated with subsequent impairment of LV function, significant mortality, ventricular dysrhythmias, and embolic phenomena. As awareness and medical imaging quality have improved, it is becoming easier to identify trabeculations that traverse the LV cavity and serve as a distinguishing feature of this disorder. Differentiating true noncompaction from mild increases in trabeculations requires prudent imaging and clinical correlation. This review seeks to discuss the potential methods of evaluating left ventricular trabeculations, the role of increased trabeculations in cardiovascular disease, and how their presence may affect clinical management.

Left Ventricular Noncompaction Diagnosis and Management Relevant to Pre-participation Screening of Athletes

Left ventricular noncompaction (LVNC) has been extensively studied over the last years, and an increasing number of cases have been reported worldwide, with a large proportion comprising young and asymptomatic subjects, including athletes. The current epidemic of LVNC is likely the consequence of several causes, that is, the increased awareness of the disease and the refined cardiovascular imaging techniques. The current diagnostic methods, based uniquely on definition of morphologic findings, do not always resolve the overlap of a physiological myocardial architecture comprising a prominent trabecular pattern from a mild phenotypic expression of the real disease. Appropriate criteria for identification and management of LVNC in athletes have, therefore, become a novel challenge for cardiologists and sport physicians, who are required to solve the question of diagnosis and appropriate management in the setting of pre-participation cardiovascular screening. Indeed, although it is important to timely identify a true myocardial disease, to reduce the burden of adverse cardiac event in a young athlete, in contrast, a misdiagnosis of LVNC may lead to unwarranted restriction of the athlete lifestyle, with detrimental psychological, social, and economic consequences. This review report has been planned, therefore, to help physicians in diagnosing and managing athletes presenting with a morphologic pattern suggestive of LVNC with specific focus on criteria for advising sport participation.

Right ventricular free wall dyskinesis in the setting of left ventricular non compaction: a case report

Background

Left ventricular non compaction is a relatively rare congenital disorder characterized by prominent trabeculations and intertrabecular recesses with the potential for thromboembolism, arrhythmias, and sudden cardiac death as adverse effects. Echocardiography has traditionally been employed as the primary mode of imaging; however, with the advent of cardiac magnetic resonance as a more precise imaging technique, the disorder known as left ventricle non compaction is becoming more broadly defined with increasing recognition of right ventricle (RV) involvement.

Case presentation

This report describes a 52-year-old Caucasian female with new onset atrial fibrillation with an unusual finding of left ventricular non compaction and right ventricular dysfunction on transthoracic echocardiogram with preserved left ventricular ejection fraction. Cardiac magnetic resonance imaging demonstrated a disproportionately affected right ventricle, with apical free wall dyskinesis.

Conclusions

This case illustrates the unique occurrence of left ventricular non compaction with preserved ejection fraction alongside RV free wall dyskinesis and RV systolic dysfunction. The significance of this is yet unknown given the paucity of existing literature. This report serves to highlight the vast heterogeneity within left ventricular non compaction as we are better able to delineate this disorder using increasingly sophisticated imaging techniques.

Clinical outcomes in patients with isolated left ventricular noncompaction and heart failure

BACKGROUND

We prospectively evaluated long-term clinical outcomes of patients diagnosed with isolated left ventricular noncompaction (ILVNC) and heart failure from a sub-Saharan African population.

METHODS AND RESULTS

Patients in this single-center study were followed at a tertiary care institution. Clinical follow-up was performed with the use of protocol-driven echocardiographic screening for ventricular thrombus every 4 months. Warfarin was maintained or initiated only if thrombus was detected with the use of echocardiography. Fifty-five patients were followed for 16.7 ± 5.9 (range 12-33) months. All individuals had left ventricular (LV) ejection fraction <50% (mean 29.6 ± 11.8%). Of the 55 patients, 7 (12.7%) died, and sudden cardiac death was the cause in 5 (71.4%). There were no differences in baseline clinical, echocardiographic, or electrocardiographic characteristics between survivors and nonsurvivors. Recurrent heart failure developed in 12 patients (21.8%); 1 patient developed a ventricular arrhythmia. No thromboembolic or major bleeding complications occurred in the 16 patients on warfarin; 1 episode of thromboembolism occurred in the 39 patients not on warfarin. Mean survival probability at 33 months was 0.64.

CONCLUSIONS

Sudden cardiac death was the most common cause of death in patients with ILVNC and heart failure. Recurrent heart failure occurred in 21.8% of patients. Development of LV thrombus and cardioembolism is uncommon in this population.

Right ventricular morphology and systolic function in left ventricular noncompaction cardiomyopathy

The distinction between normal right ventricular (RV) trabeculations from abnormal has been difficult. We evaluated whether RV volume and function are related to left ventricular (LV) noncompaction (NC) cardiomyopathy and clinical events. Trabeculations or possible LVNC by cardiac magnetic resonance imaging was retrospectively observed among 105 consecutive cases. We measured LV end-systolic (ES) noncompacted-to-compacted ratio, RV ejection fraction (EF), RV apical trabecular thickness, and RV end-diastolic (ED) noncompacted-to-compacted ratio. A control group of 40 subjects was also reviewed to assess the exploratory measures. Comparing those with LVES noncompacted-to-compacted ratio ≥2, those with LVES noncompacted-to-compacted ratio <2, and the normal control group, adjusted means for RV apical trabecular thickness and RVED noncompacted-to-compacted ratio were generated. Logistic regression was used to evaluate the association of composite events traditionally associated with LVNC with RVEF after adjustment for aforementioned covariates, cardiovascular risk factors, delayed enhancement, LVEF, and LVES noncompacted-to-compacted ratio. Analysis of RV morphology found greater apical trabecular thickness among those with LVES noncompacted-to-compacted ratio ≥2 compared with those with LVES noncompacted-to-compacted ratio <2 or normal control group (31 ± 5 vs 27 ± 2.6 vs 22 ± 4 mm; p = 0.03 and p = 0.003, respectively). There was no difference between the groups in relation to the RVED noncompacted-to-compacted ratio. Low RVEF and LVES noncompacted-to-compacted ratio ≥2 had significant association with clinical events in this population even after adjusting for clinical and imaging parameters (p = 0.04 and p <0.001, respectively). In conclusion, RV dysfunction in a morphologic LVNC population is strongly associated with adverse clinical events. LVNC is associated with increased trabeculations of the RV apex.

Embryonic cardiac chamber maturation: Trabeculation, conduction, and cardiomyocyte proliferation

Congenital heart diseases are some of the most common human birth defects. Though some congenital heart defects can be surgically corrected, treatment options for other congenital heart diseases are very limited. In many congenital heart diseases, genetic defects lead to impaired embryonic heart development or growth. One of the key development processes in cardiac development is chamber maturation, and alterations in this maturation process can manifest as a variety of congenital defects including non-compaction, systolic dysfunction, diastolic dysfunction, and arrhythmia. During development, to meet the increasing metabolic demands of the developing embryo, the myocardial wall undergoes extensive remodeling characterized by the formation of muscular luminal protrusions called cardiac trabeculae, increased cardiomyocyte mass, and development of the ventricular conduction system. Though the basic morphological and cytological changes involved in early heart development are clear, much remains unknown about the complex biomolecular mechanisms governing chamber maturation. In this review, we highlight evidence suggesting that a wide variety of basic signaling pathways and biomechanical forces are involved in cardiac wall maturation.

Implications of genetic testing in noncompaction/hypertrabeculation

Noncompaction/hypertrabeculation is increasingly being recognized in children and adults, yet we understand little about the causes of disease. Genes associated with noncompaction/hypertrabeculation have been identified, but how can these assist in clinical management? Genomic technologies have also expanded tremendously, making testing more comprehensive, but they also present new questions given the tremendous diversity of phenotypes and variability of genomes. Here we present genetic evaluation strategies and assess clinical testing options for noncompaction/hypertrabeculation. We assess genes/gene panels offered by clinical laboratories and the potential for high-throughput sequencing to fuel further discovery. We discuss challenges in cardiovascular genetics, such as interpretation of genomic variants, prediction and disease penetrance.

Left ventricular twist in left ventricular noncompaction

AIMS

Left ventricular (LV) twist is an important component of systolic function. The effect of abnormal LV twist on adverse remodelling of the heart in left ventricular noncompaction (LVNC) is unknown. This study used speckle-tracking echocardiography to evaluate LV twist in patients with LVNC and determine whether abnormal LV twist is associated with more adverse LV remodelling.

METHODS AND RESULTS

Clinical, echocardiographic, and myocardial deformation characteristics were prospectively compared between 60 subjects diagnosed with LVNC and 59 age-matched healthy controls. Net instantaneous twist was defined as: peak apical rotation minus isochronous basal rotation. Normal rotation during systole was defined based on the 2010 ASE/EAE consensus document. Rigid body rotation (RBR) was determined present if the apex and base moved in the same direction during ejection. Rigid body rotation was found in 32 (53.3%) subjects with LVNC. The 28 subjects with LVNC and normal LV rotation had diminished apical rotation, basal rotation, and net twist compared with normal controls (P < 0.0001). Patients with LVNC and RBR had worse NYHA functional status (P < 0.0001), but similar echocardiographic indices of remodelling, ejection fraction, and strain parameters as those with LVNC and normal LV rotation.

CONCLUSION

Left ventricular twist is diminished in subjects with LVNC and normal LV rotation. Rigid body rotation occurs in 53.3% of subjects with LVNC and is not associated with more adverse remodelling than subjects with LVNC and normal LV rotation.

Recent advances in the epidemiology, pathogenesis and prognosis of acute heart failure and cardiomyopathy in Africa

This review addresses recent advances in the epidemiology, pathogenesis and prognosis of acute heart failure and cardiomyopathy based on research conducted in Africa. We searched Medline/PubMed for publications on acute decompensated heart failure and cardiomyopathy in Africa for the past 5 years (ie, 1 January 2008 to 31 December 2012). This was supplemented with personal communications with colleagues from Africa working in the field. A large prospective registry has shown that acute decompensated heart failure is caused by hypertension, cardiomyopathy and rheumatic heart disease in 90% of cases, a pattern that is in contrast with the dominance of coronary artery disease in North America and Europe. Furthermore, acute heart failure is a disease of the young with a mean age of 52 years, occurs equally in men and women, and is associated with high mortality at 6 months (∼18%), which is, however, similar to that observed in non-African heart failure registries, suggesting that heart failure has a dire prognosis globally, regardless of aetiology. The molecular genetics of dilated cardiomyopathy, hypertrophic cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy in Africans is consistent with observations elsewhere in the world; the unique founder effects in the Afrikaner provide an opportunity for the study of genotype-phenotype correlations in large numbers of individuals with cardiomyopathy due to the same mutation. Advances in the understanding of the molecular mechanisms of peripartum cardiomyopathy have led to promising clinical trials of bromocriptine in the treatment of peripartum heart failure. The key challenges of management of heart failure are the urgent need to increase the use of proven treatments by physicians, and the control of hypertension in primary care and at the population level.

Trabeculated (noncompacted) and compact myocardium in adults: the multi-ethnic study of atherosclerosis

BACKGROUND

A high degree of noncompacted (trabeculated) myocardium in relationship to compact myocardium (trabeculated to compact myocardium [T/M] ratio >2.3) has been associated with a diagnosis of left ventricular noncompaction (LVNC). The purpose of this study was to determine the normal range of the T/M ratio in a large population-based study and to examine the relationship to demographic and clinical parameters.

METHODS AND RESULTS

The thickness of trabeculation and the compact myocardium were measured in 8 left ventricular regions on long axis cardiac MR steady-state free precession cine images in 1000 participants (551 women; 68.1±8.9 years) of the Multi-Ethnic Study of Atherosclerosis cohort. Of 323 participants without cardiac disease or hypertension and with all regions evaluable, 140 (43%) had a T/M ratio >2.3 in at least 1 region; in 20 of 323 (6%), T/M >2.3 was present in >2 regions. A multivariable linear regression model revealed no association of age, sex, ethnicity, height, and weight with maximum T/M ratio in participants without cardiac disease or hypertension (P>0.05). In the entire cohort (n=1000), left ventricular ejection fraction (β=-0.02/%; P=0.015), left ventricular end-diastolic volume (β=0.01/mL; P<0.0001), and left ventricular end-systolic volume (β=0.01/mL; P<0.001) were associated with maximum T/M ratio in adjusted models, whereas there was no association with hypertension or myocardial infarction (P>0.05). At the apical level, T/M ratios were significantly lower when obtained on short- compared with long-axis images (P=0.017).

CONCLUSIONS

A ratio of T/M of >2.3 is common in a large population-based cohort. These results suggest re-evaluation of the current cardiac MR criteria for left ventricular noncompaction may be necessary.