Modern Imaging Techniques in Cardiomyopathies

Detecting cardiac injury: the next generation of high-sensitivity cardiac troponins improving diagnostic outcomes

Cardiac injury, encompassing a spectrum of heart muscle damage, requires prompt and accurate diagnosis to improve patient outcomes. Early detection using cardiac biomarkers is vital for timely intervention and reducing mortality. This review highlights the role of high-sensitivity cardiac troponins (hs-cTns) in diagnosing cardiac injury. This article offers an overview of cardiac injury, including its causes, diagnostic challenges, and the evolution of biomarkers, up to the development and commercialization of "high-sensitivity" (hs-) cTns. The molecular structure of cardiac isoforms cTnI and cTnT, release kinetics, guidelines incorporation, diagnostic performance, and clinical application will be analyzed. It is concluded that the advent of hs-cTn assays has further expanded diagnostic capabilities by enabling the detection of low-level cTn elevations, which were previously undetectable using conventional methods. This enhanced sensitivity allows earlier identification of even minor cardiac injuries, facilitating prompt intervention and improving patient outcomes. However, this increased sensitivity also introduces interpretive challenges in understanding the nature of cardiac involvement, especially in distinguishing mild cTn elevations that may signify non-ischemic cardiac injury or be associated with other non-cardiac conditions.

Utility of Cardiac CT for Cardiomyopathy Phenotyping

Cardiac computed tomography (CT) has rapidly advanced, becoming an invaluable tool for diagnosing and prognosticating various cardiovascular diseases. While echocardiography and cardiac magnetic resonance imaging (CMR) remain the gold standards for myocardial assessment, modern CT technologies offer enhanced spatial resolution, making it an essential tool in clinical practice. Cardiac CT has expanded beyond coronary artery disease evaluation, now playing a key role in assessing cardiomyopathies and structural heart diseases. Innovations like photon-counting CT enable precise estimation of myocardial extracellular volume, facilitating the detection of infiltrative disorders and myocardial fibrosis. Additionally, CT-based myocardial strain analysis allows for the classification of impaired myocardial contractility, while quantifying cardiac volumes and function remains crucial in cardiomyopathy evaluation. This review explores the emerging role of cardiac CT in cardiomyopathy phenotyping, emphasizing recent technological advancements.

The relationship between serum Lumican levels and myocardial fibrosis in patients with hypertrophic cardiomyopathy

OBJECTIVE

Hypertrophic cardiomyopathy (HCM) is the leading cause of sudden cardiac death in young individuals. Lumican, is an indicator of fibrosis. We aimed to evaluate the relation between serum Lumican levels and presence and extent of myocardial fibrosis in HCM.

METHODS

The patients diagnosed with HCM between June 2022 and March 2023 were enrolled consecutively in this prospective study. Age and gender-matched healthy individuals formed control group. Two groups were generated according to extent of late gadolinium enhancement (LGE) in HCM patients.

RESULTS

A total of 114 patients were enrolled. Serum Lumican, NT-proBNP levels and maximum wall thickness were revealed as independent risk factors associated with LGE. A cut-off value of 9.06 for Lumican was associated with 67.8% sensitivity and 65.5% specificity in prediction of LGE.

CONCLUSION

Myocardial fibrosis is one of the important mechanisms in HCM pathophysiology. LGE on cardiac magnetic resonance imaging allows comprehensive evaluation of myocardial fibrosis, the support of diagnosis with a biomarker would be beneficial in clinical practice. Our study revealed that serum Lumican level is an independent predictor of severe LGE in HCM patients. Further studies with larger patient numbers may clarify the importance of Lumican in HCM pathophysiology.

Hypertrophic Cardiomyopathy with Special Focus on Mavacamten and Its Future in Cardiology

Hypertrophic cardiomyopathy (HCM) is a heterogeneous group of heart muscle disorders that affects millions, with an incidence from 1 in 500 to 1 in 200. Factors such as genetics, age, gender, comorbidities, and environmental factors may contribute to the course of this disease. Diagnosis of HCM has improved significantly in the past few decades from simple echocardiographic evaluations to a more complex, multimodal approach embracing advanced imaging, genetic, and biomarker studies. This review focuses on Mavacamten, a selective allosteric inhibitor of cardiac myosin, as a pharmacological treatment for HCM. Patients with HCM experience pathological actomyosin interactions, leading to impaired relaxation and increased energy expenditure. Mavacamten decreases available myosin heads, reducing actomyosin cross-bridges during systole and diastole. By reducing the number of bridges left ventricular outflow tract pressure is normalized and cardiac cavities are filled. This mechanism enhances patient performance and alleviates symptoms such as chest pain and dyspnea. The results suggest the potential for Mavacamten to transform the treatment of obstructive hypertrophic cardiomyopathy. Studies to date have shown significant improvement in exercise capacity, symptom relief, and a reduction in the need for invasive procedures such as septal myectomy. Further studies are needed to confirm the clinical results.

The Relationship Between Global Left Ventricular Function, as Indicated by the Tei Index, and Long-Term Survival in Patients With Non-Ischemic, Dilated Cardiomyopathy

AIM

Idiopathic dilated cardiomyopathy (DCM) is one of the leading causes of low ejection fraction (EF) heart failure (HF). The Tei index is a reliable marker that reflects both left ventricular (LV) systolic and diastolic function, and it has prognostic value in patients with DCM. We aimed to investigate the relationship between the Tei index and long-term survival in non-ischemic, DCM patients.

MATERIAL AND METHODS

The present study included 98 patients with non-ischemic DCM. The mean survival time of the patients was 59 mos.

RESULTS

The Tei index was prominently higher in patients who died (0.64±0.08 vs 0.71±0.12, respectively; p=0.01). LV end-systolic volume and LV ejection fraction (LVEF) were independent prognostic factors and predicted worse long-term survival. Additionally, the patients with LVEF ≥32.7 % and the Tei index ≤0.76 had significantly longer survival.

CONCLUSION

The present study showed that the Tei index was significantly associated with mortality and the patients with both low LVEF (≤32.7 %) and high Tei index (≥0.76) values had a shorter life expectancy. As a result, we suggest that the Tei index may be a useful echocardiographic marker to predict long-term survival in DCM patients.

The Role of Multimodality Imaging in Pediatric Cardiomyopathies

Cardiomyopathies are a heterogeneous group of myocardial diseases representing the first cause of heart transplantation in children. Diagnosing and classifying the different phenotypes can be challenging, particularly in this age group, where cardiomyopathies are often overlooked until the onset of severe symptoms. Cardiovascular imaging is crucial in the diagnostic pathway, from screening to classification and follow-up assessment. Several imaging modalities have been proven to be helpful in this field, with echocardiography undoubtedly representing the first imaging approach due to its low cost, lack of radiation, and wide availability. However, particularly in this clinical context, echocardiography may not be able to differentiate from cardiomyopathies with similar phenotypes and is often complemented with cardiovascular magnetic resonance. The latter allows a radiation-free differentiation between different phenotypes with unique myocardial tissue characterization, thus identifying the presence and extent of myocardial fibrosis. Nuclear imaging and computed tomography have a complementary role, although they are less used in daily clinical practice due to the concern related to the use of radiation in pediatric patients. However, these modalities may have some advantages in evaluating children with cardiomyopathies. This paper aims to review the strengths and limitations of each imaging modality in evaluating pediatric patients with suspected or known cardiomyopathies.

A Comprehensive Review of Dilated Cardiomyopathy in Pre-clinical Animal Models in Addition to Herbal Treatment Options and Multi-modality Imaging Strategies

Dilated cardiomyopathy (DCM) is distinguished by ventricular chamber expansion, systolic dysfunction, and normal left ventricular (LV) wall thickness, and is mainly caused due to genetic or environmental factors; however, its aetiology is undetermined in the majority of patients. The focus of this work is on pathogenesis, small animal models, as well as the herbal medicinal approach, and the most recent advances in imaging modalities for patients with dilated cardiomyopathy. Several small animal models have been proposed over the last few years to mimic various pathomechanisms that contribute to dilated cardiomyopathy. Surgical procedures, gene mutations, and drug therapies are all characteristic features of these models. The pros and cons, including heart failure stimulation of extensively established small animal models for dilated cardiomyopathy, are illustrated, as these models tend to procure key insights and contribute to the development of innovative treatment techniques for patients. Traditional medicinal plants used as treatment in these models are also discussed, along with contemporary developments in herbal therapies. In the last few decades, accurate diagnosis, proper recognition of the underlying disease, specific risk stratification, and forecasting of clinical outcome, have indeed improved the health of DCM patients. Cardiac magnetic resonance (CMR) is the bullion criterion for assessing ventricular volume and ejection fraction in a reliable and consistent direction. Other technologies, like strain analysis and 3D echocardiography, have enhanced this technique's predictive and therapeutic potential. Nuclear imaging potentially helps doctors pinpoint the causative factors of left ventricular dysfunction, as with cardiac sarcoidosis and amyloidosis.

Characterization of motion patterns by a spatio-temporal saliency descriptor in cardiac cine MRI

BACKGROUND AND OBJECTIVE

Abnormalities of the heart motion reveal the presence of a disease. However, a quantitative interpretation of the motion is still a challenge due to the complex dynamics of the heart. This work proposes a quantitative characterization of regional cardiac motion patterns in cine magnetic resonance imaging (MRI) by a novel spatio-temporal saliency descriptor.

METHOD

The strategy starts by dividing the cardiac sequence into a progression of scales which are in due turn mapped to a feature space of regional orientation changes, mimicking the multi-resolution decomposition of oriented primitive changes of visual systems. These changes are estimated as the difference between a particular time and the rest of the sequence. This decomposition is then temporarily and regionally integrated for a particular orientation and then for the set of different orientations. A final spatio-temporal 4D saliency map is obtained as the summation of the previously integrated information for the available scales. The saliency dispersion of this map was computed in standard cardiac locations as a measure of the regional motion pattern and was applied to discriminate control and hypertrophic cardiomyopathy (HCM) subjects during the diastolic phase.

RESULTS

Salient motion patterns were estimated from an experimental set, which consisted of 3D sequences acquired by MRI from 108 subjects (33 control, 35 HCM, 20 dilated cardiomyopathy (DCM), and 20 myocardial infarction (MINF) from heterogeneous datasets). HCM and control subjects were classified by an SVM that learned the salient motion patterns estimated from the presented strategy, by achieving a 94% AUC. In addition, statistical differences (test t-student, p<0.05) were found among groups of disease in the septal and anterior ventricular segments at both the ED and ES, with salient motion characteristics aligned with existing knowledge on the diseases.

CONCLUSIONS

Regional wall motion abnormality in the apical, anterior, basal, and inferior segments was associated with the saliency dispersion in HCM, DCM, and MINF compared to healthy controls during the systolic and diastolic phases. This saliency analysis may be used to detect subtle changes in heart function.

Cardiac magnetic resonance imaging in preeclampsia complicated by pulmonary edema shows myocardial edema with normal left ventricular systolic function

BACKGROUND

Preeclampsia complicates approximately 5% of all pregnancies. When pulmonary edema occurs, it accounts for 50% of preeclampsia-related mortality. Currently, there is no consensus on the degree to which left ventricular systolic dysfunction contributes to the development of pulmonary edema.

OBJECTIVE

This study aimed to use cardiac magnetic resonance imaging to detect subtle changes in left ventricular systolic function and evidence of acute left ventricular dysfunction (through tissue characterization) in women with preeclampsia complicated by pulmonary edema compared with both preeclamptic and normotensive controls.

STUDY DESIGN

Cases were postpartum women aged ≥18 years presenting with preeclampsia complicated by pulmonary edema. Of note, 2 control groups were recruited: women with preeclampsia without pulmonary edema and women with normotensive pregnancies. All women underwent echocardiography and 1.5T cardiac magnetic resonance imaging with native T1 and T2 mapping. Gadolinium contrast was administered to cases only. Because of small sample sizes, a nonparametric test (Kruskal-Wallis) with pairwise posthoc analysis using Bonferroni correction was used to compare the differences between the groups. Cardiac magnetic resonance images were interpreted by 2 independent reporters. The intraclass correlation coefficient was calculated to assess interobserver reliability.

RESULTS

Here, 20 women with preeclampsia complicated by pulmonary edema, 13 women with preeclampsia (5 with severe features and 8 without severe features), and 6 normotensive controls were recruited. There was no difference in the baseline characteristics between groups apart from the expected differences in blood pressure. Left atrial sizes were similar across all groups. Women with preeclampsia complicated by pulmonary edema had increased left ventricular mass (P=.01) but had normal systolic function compared with the normotensive controls. Furthermore, they had elevated native T1 values (P=.025) and a trend toward elevated T2 values (P=.07) in the absence of late gadolinium enhancement consistent with myocardial edema. Moreover, myocardial edema was present in all women with eclampsia or hemolysis, elevated liver enzymes, and low platelet count. Women with preeclampsia without severe features had similar findings to the normotensive controls. All cardiac magnetic resonance imaging measurements showed a very high level of interobserver correlation.

CONCLUSION

This study focused on cardiac magnetic resonance imaging in women with preeclampsia complicated by pulmonary edema, eclampsia, and hemolysis, elevated liver enzymes, and low platelet count. We have demonstrated normal systolic function with myocardial edema in women with preeclampsia with these severe features. These findings implicate an acute myocardial process as part of this clinical syndrome. The pathogenesis of myocardial edema and its relationship to pulmonary edema require further elucidation. With normal left atrial sizes, any hemodynamic component must be acute.

Cardiac magnetic resonance in the assessment of hypertrophic cardiomyopathy phenotypes and stages - pictorial review

The aim of this paper is to present recent advances in hypertrophic cardiomyopathy (HCM) diagnosis and treatment based on a literature review. Special emphasis has been placed on the role of cardiac magnetic resonance imaging (CMR) for the assessment of morphological and functional consequences of different stages of HCM including prognostication. The text is illustrated with the images and data of the HCM patients diagnosed with CMR study in our hospital. CMR is an important tool, particularly relevant in novel risk factors and LV dysfunction groups. The HCM group with overt left ventricular dysfunction is underrecognized, often labelled by clinicians as dilated cardiomyopathy. Advanced diagnostic and management strategies effectively influence the natural history of HCM.

Current use of cardiac magnetic resonance in tertiary referral centres for the diagnosis of cardiomyopathy: the ESC EORP Cardiomyopathy/Myocarditis Registry

Aims 

Cardiac magnetic resonance (CMR) is recommended in the diagnosis of cardiomyopathies, but it is time-consuming, expensive, and limited in availability in some European regions. The aim of this study was to determine the use of CMR in cardiomyopathy patients enrolled into the European Society of Cardiology (ESC) cardiomyopathy registry [part of the EURObservational Research Programme (EORP)].

Methods and results 

Three thousand, two hundred, and eight consecutive adult patients (34.6% female; median age: 53.0 ± 15 years) with cardiomyopathy were studied: 1260 with dilated (DCM), 1739 with hypertrophic (HCM), 66 with restrictive (RCM), and 143 with arrhythmogenic right ventricular cardiomyopathy (ARVC). CMR scans were performed at baseline in only 29.4% of patients. CMR utilization was variable according to cardiomyopathy subtypes: from 51.1% in ARVC to 36.4% in RCM, 33.8% in HCM, and 20.6% in DCM (P < 0.001). CMR use in tertiary referral centres located in different European countries varied from 1% to 63.2%. Patients undergoing CMR were younger, less symptomatic, less frequently had implantable cardioverter-defibrillator (ICD)/pacemaker implanted, had fewer cardiovascular risk factors and comorbidities (P < 0.001). In 28.6% of patients, CMR was used along with transthoracic echocardiography (TTE); 67.6% patients underwent TTE alone, and 0.9% only CMR.

Conclusion 

Less than one-third of patients enrolled in the registry underwent CMR and the use varied greatly between cardiomyopathy subtypes, clinical profiles of patients, and European tertiary referral centres. This gap with current guidelines needs to be considered carefully by scientific societies to promote wider availability and use of CMR in patients with cardiomyopathies.

Clinical Heart Failure Stratification Through Native T1 Mapping: Experience of a Referral Service

BACKGROUND

Diffuse cardiac fibrosis is an important factor in the prognostic assessment of patients with ventricular dysfunction. Cardiovascular magnetic resonance imaging (CMR) native T1 mapping is highly sensitive and considered an independent predictor of all-cause mortality and heart failure (HF) development in patients with cardiomyopathy.

OBJECTIVES

To evaluate the feasibility of native T1 mapping assessment in patients with HF in a cardiology referral hospital and its association with structural parameters and functional profile.

METHODS

Cross-sectional study with adult patients with HF NYHA functional classes I and II, ischemic and non-ischemic, followed in a referral hospital, who underwent CMR. Native T1 values were analyzed for structural parameters, comorbidities, etiology, and categorization of HF by left ventricular ejection fraction (LVEF). Analyses were performed with a significance level of 5%.

RESULTS

Enrollment of 134 patients. Elevated native T1 values were found in patients with greater dilation (1004.9 vs 1042.7ms, p = 0.001), ventricular volumes (1021.3 vs 1050.3ms, p <0.01) and ventricular dysfunction (1010.1 vs 1053.4ms, p <0.001), also present when the non-ischemic group was analyzed separately. Patients classified as HF with reduced ejection fraction had higher T1 values than those with HF and preserved ejection fraction (HFPEF) (992.7 vs 1054.1ms, p <0.001). Of those with HFPEF, 55.2% had higher T1.

CONCLUSIONS

CMR T1 mapping is feasible for clinical HF evaluation. There was a direct association between higher native T1 values and lower ejection fraction, and with larger LV diameters and volumes, regardless of the etiology of HF.

Cardiac Magnetic Resonance Imaging for Nonischemic Cardiac Disease in Out-of-Hospital Cardiac Arrest Survivors Treated with Targeted Temperature Management: A Multicenter Retrospective Analysis

(1) Background: Cardiac magnetic resonance (CMR) imaging is an emerging tool for investigating nonischemic cardiomyopathies and cardiac systemic disease. However, data on the cardiac arrest population are limited. This study aimed to evaluate the usefulness of CMR imaging in out-of-hospital cardiac arrest (OHCA) survivors treated with targeted temperature management (TTM). (2) Methods: We conducted the retrospective observational study using a multicenter registry of adult non-traumatic comatose OHCA survivors who underwent TTM between January 2010 and December 2019. Of the 949 patients, 389 with OHCA of non-cardiac cause, 145 with significant lesions in the coronary artery, 151 who died during TTM, 81 without further evaluation due to anticipated poor neurological outcome, and 51 whose etiology is underlying disease were excluded. In 36 of the 132 remaining patients, the etiologies included variant angina, long QT syndrome, and complete atrioventricular block in ancillary studies. Fifty-six patients were diagnosed idiopathic ventricular fibrillation without CMR. (3) Results: CMR imaging was performed in the remaining 40 patients with cardiac arrest of unknown cause. The median time from cardiac arrest to CMR imaging was 10.1 days. The CMR finding was normal in 23 patients, non-diagnostic in 12, and abnormal in 5, which suggested non-ischemic cardiomyopathy but did not support the final diagnosis. (4) Conclusions: CMR imaging may not be useful for identifying unknown causes of cardiac arrest in OHCA survivors treated with targeted temperature management without definitive diagnosis even after coronary angiography, echocardiography, and electrophysiology studies. However, further large-scale studies will be needed to confirm these findings.

A new SCN5A variant in a patient with idiopathic ventricular fibrillation: The dark side of cardiac imaging

We present the case of a patient with recurrent episodes of ventricular fibrillation without evidence of structural cardiac diseases on imaging techniques and negative genetic testing for the most common primary arrhythmia syndromes. A new variant c.6023C>T p.Pro2008Leu of the SCN5A protein, responsible for the sodium inward current (I_Na) through the cardiomyocytes, was found. A likely pathogenic effect of this gene variant was hypothesized.

Dilated cardiomyopathies and non-compaction cardiomyopathy

Dilated cardiomyopathy (DCM) is the most common form of cardiomyopathy and one of the most common causes of heart failure. It is characterized by left or biventricular dilation and a reduced systolic function. The causes are manifold and range from myocarditis to alcohol and other toxins, to rheumatological, endocrinological, and metabolic diseases. Peripartum cardiomyopathy is a special form that occurs at the end of or shortly after pregnancy. Genetic mutations can be detected in approximately 30-50% of DCM patients. Owing to the growing possibilities of genetic diagnostics, increasingly more triggering variants and hereditary mechanisms emerge. This is particularly important with regard to risk stratification for patients with variants with an increased risk of arrhythmias. Patient prognosis is determined by the occurrence of heart failure and arrhythmias. In addition to the treatment of the underlying disease or the elimination of triggering harmful toxins, therapy consists in guideline-directed heart failure treatment including drug and device therapy.

Phenotypes of hypertrophic cardiomyopathy: genetics, clinics, and modular imaging

Hypertrophic cardiomyopathy (HCM) is the most common cardiovascular disease with genetic transmission, characterized by the hypertrophy of any segment of the left ventricle (LV), not totally explained by improper loading conditions, with LV systolic function preserved, increased, or reduced. The histopathological mechanism involved in HCM refers to the primary injury of the myocardium, as follows: disorganized array of myocytes, extracellular matrix modification, microvascular dysfunction, with subsequent appearance of myocardial fibrosis. Multiple sarcomere proteins mutations are responsible for HCM, but two of them are involved in 70% of the cases of HCM: β-myosin heavy chain (MYH7) and myosin-binding protein C (MYBPC3). The development of new genetic techniques involving genome editing is promising to discover a gene therapy for patients with HCM. Clinical presentation may differ from asymptomatic to sudden cardiac death (SCD), the last one targeting younger adults. In this case, the diagnosis and evaluation of SCD risk factors is extremely important. The common method of diagnosis is transthoracic echocardiography, but cardiac magnetic resonance (CMR) imaging represents "gold standard" in the evaluation of HCM patients. Treatment includes pharmacological therapy, surgery, alcohol ablation, and not least SCD prevention.

Advances in MRI Applications to Diagnose and Manage Cardiomyopathies

PURPOSE OF REVIEW

The prevalence of heart failure continues to rise, and imaging characterization of the cardiomyopathic process is important for identifying myocardial disease, initiating appropriate treatment, and improving outcomes. We aimed to summarize recent advances in cardiac magnetic resonance imaging (CMR) applications for the diagnosis, characterization, and implications on management of various cardiomyopathies.

RECENT FINDINGS

Parametric mapping by CMR has emerged as an important advancement in quantification of myocardial fibrosis, increased extracellular space, and myocardial edema. In addition, improved assessment of myocardial function with myocardial strain assessment may provide early identification of patients at risk and determining responsiveness to therapeutic interventions. Novel MRI techniques and the advent of artificial intelligence may help to uncover important mechanistic insights into the cardiomyopathic process. Innovative CMR techniques continue to evolve, and it will be of interest to determine how these advances can be incorporated into clinical practice to improve diagnosis, treatment, and management of patients with cardiomyopathies.

Cardiovascular magnetic resonance: contribution to the exploration of cardiomyopathies

Background and aims

Magnetic resonance imaging is a non-invasive and non-irradiating imaging method, complementary to cardiac ultrasound in the assessment of cardiovascular disease and implicitly of cardiomyopathies. Although it is not a first intention imaging method, it is superior in the assessment of cardiac volumes, left ventricular ejection fraction, in the analysis of cardiac wall dyskinesia and myocardial tissue characteristics with and without using a contrast agent. The purpose of this paper is to review the current knowledge regarding cardiovascular magnetic resonance imaging (CMR) and its applications in cardiomyopathy analysis.

Methods

In order to create this review, relevant articles were searched and analyzed by using MeSH terms such as: “cardiac magnetic resonance imaging”, “cardiomyopathy”, “myocardial fibrosis”. Three main international databases PubMed, Web of Science and Medscape were searched. We carried out a narrative review focused on the current indications of cardiovascular magnetic resonance imaging in cardiomyopathies, both common and raret, of ischemic and nonischemic types.

Results

Cardiac magnetic resonance imaging has a very important role in the diagnosis, assessment and prognosis of common cardiomyopathies (the dilated, hypertrophic and inflammatory types) or other more rare ones such as (amyloidosis, arrhythmogenic right ventricular, non-compaction or Takotsubo cardiomyopathy), as it represents the gold standard for evaluating the ejection fraction, ventricular volumes and mass. CMR techniques, such as late gadolinium enhancement, T1 and T2 mapping have proven their usefulness, helping differentiate between ischemic (subendocardial enhancement) and nonischemic cardiomyopathy (varied pattern) or also establish the etiology. Another important feature of this imaging technique is that it can establish the myocardial viability, thus the chance of contractile recovery after revascularization. This feature is based on the transmural extent of LGE, left ventricle wall thickness and the assessment of the contractile reserve after administration of low dose dobutamine.

Conclusions

Cardiovascular magnetic resonance imaging is an indispensable tool, with proven efficiency, capable of providing the differential diagnosis between ischemic and nonischemic cardiomyopathy or establishing the etiology in the nonischemic type. In addition, these findings have a prognostic value, they may guide the patient management plan and, if necessary, can evaluate treatment response. Therefore, this technique should be part of any routine investigation of various cardiomyopathies.

Hypertrophic cardiomyopathy: genetics and clinical perspectives

Hypertrophic cardiomyopathy (HCM) is the most common inherited heart disease and defined by unexplained isolated progressive myocardial hypertrophy, systolic and diastolic ventricular dysfunction, arrhythmias, sudden cardiac death and histopathologic changes, such as myocyte disarray and myocardial fibrosis. Mutations in genes encoding for proteins of the contractile apparatus of the cardiomyocyte, such as β-myosin heavy chain and myosin binding protein C, have been identified as cause of the disease. Disease is caused by altered biophysical properties of the cardiomyocyte, disturbed calcium handling, and abnormal cellular metabolism. Mutations in sarcomere genes can also activate other signaling pathways via transcriptional activation and can influence non-cardiac cells, such as fibroblasts. Additional environmental, genetic and epigenetic factors result in heterogeneous disease expression. The clinical course of the disease varies greatly with some patients presenting during childhood while others remain asymptomatic until late in life. Patients can present with either heart failure symptoms or the first symptom can be sudden death due to malignant ventricular arrhythmias. The morphological and pathological heterogeneity results in prognosis uncertainty and makes patient management challenging. Current standard therapeutic measures include the prevention of sudden death by prohibition of competitive sport participation and the implantation of cardioverter-defibrillators if indicated, as well as symptomatic heart failure therapies or cardiac transplantation. There exists no causal therapy for this monogenic autosomal-dominant inherited disorder, so that the focus of current management is on early identification of asymptomatic patients at risk through molecular diagnostic and clinical cascade screening of family members, optimal sudden death risk stratification, and timely initiation of preventative therapies to avoid disease progression to the irreversible adverse myocardial remodeling stage. Genetic diagnosis allowing identification of asymptomatic affected patients prior to clinical disease onset, new imaging technologies, and the establishment of international guidelines have optimized treatment and sudden death risk stratification lowering mortality dramatically within the last decade. However, a thorough understanding of underlying disease pathogenesis, regular clinical follow-up, family counseling, and preventative treatment is required to minimize morbidity and mortality of affected patients. This review summarizes current knowledge about molecular genetics and pathogenesis of HCM secondary to mutations in the sarcomere and provides an overview about current evidence and guidelines in clinical patient management. The overview will focus on clinical staging based on disease mechanism allowing timely initiation of preventative measures. An outlook about so far experimental treatments and potential for future therapies will be provided.

Considerations for an In Vitro, Cell-Based Testing Platform for Detection of Adverse Drug-Induced Inotropic Effects in Early Drug Development. Part 1: General Considerations for Development of Novel Testing Platforms

Drug-induced effects on cardiac contractility can be assessed through the measurement of the maximal rate of pressure increase in the left ventricle (LVdP/dt_max) in conscious animals, and such studies are often conducted at the late stage of preclinical drug development. Detection of such effects earlier in drug research using simpler, in vitro test systems would be a valuable addition to our strategies for identifying the best possible drug development candidates. Thus, testing platforms with reasonably high throughput, and affordable costs would be helpful for early screening purposes. There may also be utility for testing platforms that provide mechanistic information about how a given drug affects cardiac contractility. Finally, there could be in vitro testing platforms that could ultimately contribute to the regulatory safety package of a new drug. The characteristics needed for a successful cell or tissue-based testing platform for cardiac contractility will be dictated by its intended use. In this article, general considerations are presented with the intent of guiding the development of new testing platforms that will find utility in drug research and development. In the following article (part 2), specific aspects of using human-induced stem cell-derived cardiomyocytes for this purpose are addressed.

Pathobiology of cardiovascular diseases: an update

This article introduces the Second Special Issue of Cardiovascular Pathology (CVP), the official journal of the Society for Cardiovascular Pathology (SCVP). This CVP Special Issue showcases a series of commemorative review articles in celebration of the 25th anniversary of CVP originally published in 2016 and now compiled into a virtual collection with online access for the cardiovascular pathology community. This overview also provides updates on the major categories of cardiovascular diseases from the perspective of cardiovascular pathologists, highlighting publications from CVP, as well as additional important review articles and clinicopathologic references.

Cardiomyopathy in Children: Classification and Diagnosis: A Scientific Statement From the American Heart Association

In this scientific statement from the American Heart Association, experts in the field of cardiomyopathy (heart muscle disease) in children address 2 issues: the most current understanding of the causes of cardiomyopathy in children and the optimal approaches to diagnosis cardiomyopathy in children. Cardiomyopathies result in some of the worst pediatric cardiology outcomes; nearly 40% of children who present with symptomatic cardiomyopathy undergo a heart transplantation or die within the first 2 years after diagnosis. The percentage of children with cardiomyopathy who underwent a heart transplantation has not declined over the past 10 years, and cardiomyopathy remains the leading cause of transplantation for children >1 year of age. Studies from the National Heart, Lung, and Blood Institute-funded Pediatric Cardiomyopathy Registry have shown that causes are established in very few children with cardiomyopathy, yet genetic causes are likely to be present in most. The incidence of pediatric cardiomyopathy is ≈1 per 100 000 children. This is comparable to the incidence of such childhood cancers as lymphoma, Wilms tumor, and neuroblastoma. However, the published research and scientific conferences focused on pediatric cardiomyopathy are sparcer than for those cancers. The aim of the statement is to focus on the diagnosis and classification of cardiomyopathy. We anticipate that this report will help shape the future research priorities in this set of diseases to achieve earlier diagnosis, improved clinical outcomes, and better quality of life for these children and their families.

Dilated cardiomyopathy

Dilated cardiomyopathy (DCM) is a clinical diagnosis characterized by left ventricular or biventricular dilation and impaired contraction that is not explained by abnormal loading conditions (for example, hypertension and valvular heart disease) or coronary artery disease. Mutations in several genes can cause DCM, including genes encoding structural components of the sarcomere and desmosome. Nongenetic forms of DCM can result from different aetiologies, including inflammation of the myocardium due to an infection (mostly viral); exposure to drugs, toxins or allergens; and systemic endocrine or autoimmune diseases. The heterogeneous aetiology and clinical presentation of DCM make a correct and timely diagnosis challenging. Echocardiography and other imaging techniques are required to assess ventricular dysfunction and adverse myocardial remodelling, and immunological and histological analyses of an endomyocardial biopsy sample are indicated when inflammation or infection is suspected. As DCM eventually leads to impaired contractility, standard approaches to prevent or treat heart failure are the first-line treatment for patients with DCM. Cardiac resynchronization therapy and implantable cardioverter-defibrillators may be required to prevent life-threatening arrhythmias. In addition, identifying the probable cause of DCM helps tailor specific therapies to improve prognosis. An improved aetiology-driven personalized approach to clinical care will benefit patients with DCM, as will new diagnostic tools, such as serum biomarkers, that enable early diagnosis and treatment.

Cardiomyopathies: An Overview

The nonischemic cardiomyopathies are a diverse group of cardiac disorders that frequently cause heart failure and death and are now recognized with increasing frequency. There has been substantial progress in the clinical recognition and understanding of the natural history of these conditions. Well-established and new techniques of cardiac imaging are also helpful in this regard. Basic scientists are elucidating the pathogenesis and pathobiology of individual cardiomyopathies. In this compendium, some of the most important advances in this field are reviewed. Scientific opportunities to enhance further collaborative research to accelerate progress are identified.

Hypertrophic Cardiomyopathy: Genetics, Pathogenesis, Clinical Manifestations, Diagnosis, and Therapy

Hypertrophic cardiomyopathy (HCM) is a genetic disorder that is characterized by left ventricular hypertrophy unexplained by secondary causes and a nondilated left ventricle with preserved or increased ejection fraction. It is commonly asymmetrical with the most severe hypertrophy involving the basal interventricular septum. Left ventricular outflow tract obstruction is present at rest in about one third of the patients and can be provoked in another third. The histological features of HCM include myocyte hypertrophy and disarray, as well as interstitial fibrosis. The hypertrophy is also frequently associated with left ventricular diastolic dysfunction. In the majority of patients, HCM has a relatively benign course. However, HCM is also an important cause of sudden cardiac death, particularly in adolescents and young adults. Nonsustained ventricular tachycardia, syncope, a family history of sudden cardiac death, and severe cardiac hypertrophy are major risk factors for sudden cardiac death. This complication can usually be averted by implantation of a cardioverter-defibrillator in appropriate high-risk patients. Atrial fibrillation is also a common complication and is not well tolerated. Mutations in over a dozen genes encoding sarcomere-associated proteins cause HCM. MYH7 and MYBPC3, encoding β-myosin heavy chain and myosin-binding protein C, respectively, are the 2 most common genes involved, together accounting for ≈50% of the HCM families. In ≈40% of HCM patients, the causal genes remain to be identified. Mutations in genes responsible for storage diseases also cause a phenotype resembling HCM (genocopy or phenocopy). The routine applications of genetic testing and preclinical identification of family members represents an important advance. The genetic discoveries have enhanced understanding of the molecular pathogenesis of HCM and have stimulated efforts designed to identify new therapeutic agents.