Prognostic value of quantitative contrast-enhanced cardiovascular magnetic resonance for the evaluation of sudden death risk in patients with hypertrophic cardiomyopathy

Rare Metabolic and Endocrine Diseases with Cardiovascular Involvement: Insights from Cardiovascular Magnetic Resonance - A Review

The identification of rare diseases with cardiovascular involvement poses significant diagnostic challenges due to the rarity of the diseases, but also due to the lack of knowledge and expertise. Most of them remain underrecognized and undiagnosed, leading to clinical mismanagement and affecting the patients' prognosis, as these diseases are per definition life-threatening or chronic debilitating. This article reviews the cardiovascular involvement of the most well-known rare metabolic and endocrine diseases and their diagnostic approach through the lens of cardiovascular magnetic resonance (CMR) imaging and its prognostic role, highlighting its fundamental value compared to other imaging modalities.

Contemporary Diagnosis and Management of Hypertrophic Cardiomyopathy: The Role of Echocardiography and Multimodality Imaging

Hypertrophic cardiomyopathy (HCM) is an underdiagnosed genetic heart disease with an estimated prevalence of 0.2–0.5%. Although the prognosis of HCM is relatively good, with an annual general mortality of ~0.7%, some patients have an increased risk of sudden death, or of developing severe heart failure requiring heart transplantation or left ventricular (LV) assist device therapy. Therefore, earlier diagnosis and proper identification of high-risk patients may reduce disease-related morbidity/mortality by promoting timely treatment. Echocardiography is the primary imaging modality for patients with suspected HCM; it plays central roles in differential diagnosis from other causes of LV hypertrophy and in evaluating morphology, hemodynamic disturbances, LV function, and associated valvular disease. Echocardiography is also an essential tool for the continuous clinical management of patients with confirmed HCM. Other imaging modalities, such as cardiac computed tomography (CT) and cardiac magnetic resonance imaging (MRI), can supplement echocardiography in identifying high-risk as well as milder HCM phenotypes. The role of such multimodality imaging has been steadily expanding along with recent advancements in surgical techniques and minimally invasive procedures, and the emergence of novel pharmacotherapies directly targeting pathogenic molecules such as myosin inhibitors. Here we review essential knowledge surrounding HCM with a specific focus on structural and functional abnormalities assessed by imaging modalities, leading to treatment strategies.

Deep Neural Network for Cardiac Magnetic Resonance Image Segmentation

The analysis and interpretation of cardiac magnetic resonance (CMR) images are often time-consuming. The automated segmentation of cardiac structures can reduce the time required for image analysis. Spatial similarities between different CMR image types were leveraged to jointly segment multiple sequences using a segmentation model termed a multi-image type UNet (MI-UNet). This model was developed from 72 exams (46% female, mean age 63 ± 11 years) performed on patients with hypertrophic cardiomyopathy. The MI-UNet for steady-state free precession (SSFP) images achieved a superior Dice similarity coefficient (DSC) of 0.92 ± 0.06 compared to 0.87 ± 0.08 for a single-image type UNet (p < 0.001). The MI-UNet for late gadolinium enhancement (LGE) images also had a superior DSC of 0.86 ± 0.11 compared to 0.78 ± 0.11 for a single-image type UNet (p = 0.001). The difference across image types was most evident for the left ventricular myocardium in SSFP images and for both the left ventricular cavity and the left ventricular myocardium in LGE images. For the right ventricle, there were no differences in DCS when comparing the MI-UNet with single-image type UNets. The joint segmentation of multiple image types increases segmentation accuracy for CMR images of the left ventricle compared to single-image models. In clinical practice, the MI-UNet model may expedite the analysis and interpretation of CMR images of multiple types.

The role of multimodality imaging in patients with heart failure with reduced and preserved ejection fraction

PURPOSE OF REVIEW

The burden of clinical heart failure, both heart failure with a reduced ejection fraction (HFrEF) and with a preserved ejection fraction (HFpEF), continues to increase both nationally and globally. This review summarizes the expanding role of multimodality imaging techniques in the evaluation and management these patients.

RECENT FINDINGS

Echocardiographic assessment for heart failure continues to expand and should include a robust hemodynamic and strain assessment. Nuclear techniques have also continued to evolve and advances including computed tomography attenuation correction for single photon emission-computed tomography positron-emission tomography increase diagnostic accuracy as well as provide information such as myocardial blood flow and viability assessment. Computed tomography imaging, already well established in the assessment of coronary and valvular disease, has increasing utility in the characterization of myopathy, and cardiac magnetic resonance imaging (MRI) continues to expand its role in tissue characterization to a wider breadth of diseases, including right ventricular cardiomyopathy and left ventricle noncompaction.

SUMMARY

Although heart failure remains a clinical diagnosis based on history and examination, early imaging is critical for further assessment. Due to its widespread availability, affordability, and safety, transthoracic echocardiography has long been the mainstay tool for both initial evaluation as well as for periodic surveillance of heart failure patients, but advances in multimodality imaging are occurring at a rapid pace and promise to provide an increasing wealth of data to help manage such patients.

Comparison of Nonclassic and Classic Phenotype of Hypertrophic Cardiomyopathy Focused on Prognostic Cardiac Magnetic Resonance Parameters: A Single-Center Observational Study

Patients with nonclassic phenotypes (NCP)—more advanced stages of hypertrophic cardiomyopathy (HCM)—constitute an intriguing and heterogeneous group that is difficult to diagnose, risk-stratify, and treat, and often neglected in research projects. We aimed to compare cardiac magnetic resonance (CMR) parameters in NCP versus classic phenotypes (CP) of HCM with special emphasis given to the parameters of established and potential prognostic importance, including numerous variables not used in everyday clinical practice. The CMR studies of 88 patients performed from 2011 to 2019 were postprocessed according to the study protocol to obtain standard and non-standard parameters. In NCP, the late gadolinium enhancement extent expressed as percent of left ventricular mass (%LGE) and left ventricular mass index (LVMI) were higher, left atrium emptying fraction (LAEF) was lower, minimal left atrial volume (LAV min) was greater, and myocardial contraction fraction (MCF) and left ventricular global function index (LVGFI) were lower than in CP (p < 0.001 for all). In contrast, HCM risk score and left ventricular maximal thickness (LVMT) were similar in NCP and CP patients. No left ventricular outflow tract obstruction (LVOTO) was observed in the NCP group. Left ventricular outflow tract diameter (LVOT), aortic valve diameter (Ao), and LVOT/Ao ratio were significantly higher and anterior mitral leaflet (AML)/LVOT ratio was lower in the NCP compared to the CP group. In conclusion, significant differences in nonstandard CMR parameters were noted between the nonclassic and classic HCM phenotypes that may contribute to future studies on disease stages and risk stratification in HCM.

Relation Between Early Diastolic Mid-Ventricular Flow and Elastic Forces Indicating Aneurysm Formation in Hypertrophic Cardiomyopathy

BACKGROUND

The early diastolic paradoxical mid-ventricular flow (EDF) is suggestive of apical aneurysm (AA) formation in hypertrophic cardiomyopathy (HCM). We aimed to determine whether EDF may be a useful screening tool in patients, following the time progression of HCM to the aneurysmal stage.

METHODS

121 HCM patients with dominant hypertrophy in the mid and apical segments, based on echocardiography and/or cardiovascular magnetic resonance (CMR), were selected from our HCM database comprising 1332 patients. They were further stratified according to the presence of AA. All imaging studies in a period of 16 years (2005-2021) were considered for time progression. Mid-ventricular Doppler (PW, CW, color and color M-mode) were analyzed.

RESULTS

35 patients (29% of the study group and 2.6% of all HCM patients) had AA. EDF had a sensitivity of 92% and specificity of 98.6% for the detection of AA in the study group. In 108 patients follow-up echocardiography was performed (median 5 [3-9] studies). Sixteen patients (15%), with 10 [7-12] years follow-up, displayed progressive time changes in LV apical morphology and/or mid-LV flow. Ten patients (9%) progressed to an AA, during 7 [4-11] years follow-up. Patients progressing to AA were younger (p=0.009), with more severe LV hypertrophy (p=0.01) and more often a significant mid-LV systolic gradient (≥ 30mmHg, p<0.001). A wall thickness over 20mm had 70% sensitivity and 69% specificity in detecting evolution towards AA. With significant systolic gradient, sensitivity was 80% and specificity 62%. Furthermore, patients with AA had higher incidence of ventricular tachycardia (Log-rank p=0.03).

CONCLUSION

EDF reliably detects AA presence and should prompt for extra imaging studies. In HCM with mid and apical dominant involvement there is a progressive trend towards aneurysm formation, especially in patients with wall thickness over 20mm and significant mid-LV systolic gradient (≥30mmHg), which can be monitored through serial Doppler studies.

Strength of clinical indication and therapeutic impact of the implantable cardioverter defibrillator in patients with hypertrophic cardiomyopathy

BACKGROUND

The implantable cardioverter defibrillator(ICD) has revolutionized the management of patients with hypertrophic cardiomyopathy (HCM) at risk of sudden cardiac death (SCD). However, the identification of ideal candidates remains challenging. We aimed to describe the long-term impact of the ICD for primary prevention in patients with HCM based on stringent (high SCD risk) vs lenient indications (need for pacing/personal choice).

METHODS

Data from two Italian HCM Cardiomyopathy Units were retrospectively analyzed. Only patients >1 follow-up visits were divided into two groups according to ICD candidacy:stringent (high SCD risk) and lenient (need for pacing, patients' choice, physician advice despite lack of high SCD risk). Major cardiac events (composite of appropriate shock/intervention and SCD) was the primary endpoint. A safety endpoint was defined as a composite of inappropriate shocks and device-related complications.

RESULTS

Of 2009 patients, 252(12.5%) received an ICD, including 27(1.3%) in secondary prevention and 225(11.2%) in primary prevention (age at implantation 49 ± 16 years; men 65.3%). Among those in primary prevention, 167(74.2%) had stringent, while 58(25.8%) had lenient indications. At 5 ± 4 years, only stringent ICD patients experienced major cardiac events (2.84%/year, 5-year cumulative incidence: 8.1%, 95%CI [3.5-14.1%]). ICD-related complications were similar across stringent and lenient subgroups. However, patients implanted >60 years had a significantly higher risk of adverse events.

CONCLUSION

One third of ICD recipients with HCM in primary prevention received a lenient implantation and had no appropriate intervention. ICD implantation due to systematic upgrade in patients requiring pacing and increased risk perception may offer little advantage and increase complication rates.

Recent Non-Invasive Parameters to Identify Subjects at High Risk of Sudden Cardiac Death

Cardiovascular diseases remain among the leading causes of death worldwide and sudden cardiac death (SCD) accounts for ~25% of these deaths. Despite its epidemiologic relevance, there are very few diagnostic strategies available useful to prevent SCD mainly focused on patients already affected by specific cardiovascular diseases. Unfortunately, most of these parameters exhibit poor positive predictive accuracy. Moreover, there is also a need to identify parameters to stratify the risk of SCD among otherwise healthy subjects. This review aims to provide an update on the most relevant non-invasive diagnostic features to identify patients at higher risk of developing malignant ventricular arrhythmias and SCD.

Determinants of Exercise Capacity in Patients With Hypertrophic Cardiomyopathy

BACKGROUND

Reduced exercise capacity reflects symptom severity and clinical outcomes in patients with hypertrophic cardiomyopathy (HCM). The present study aimed to identify factors that may affect exercise capacity in patients with HCM.

METHODS

In 294 patients with HCM and preserved left ventricular (LV) ejection fraction, we compared peak oxygen consumption (peak VO₂) evaluated by cardiopulmonary exercise testing as a representative parameter of exercise tolerance with clinical and laboratory data, including N-terminal pro-hormone of brain natriuretic peptide (NT-proBNP), diastolic parameters on echocardiography, and the grade of myocardial fibrosis on cardiac magnetic resonance imaging (CMR).

RESULTS

Median peak VO₂, was 29.0 mL/kg/min (interquartile range [IQR], 25.0-34.0). Age (estimated β = -0.140, P < 0.001), female sex (β = -5.362, P < 0.001), NT-proBNP (β = -1.256, P < 0.001), and E/e' ratio on echocardiography (β = -0.209, P = 0.019) were significantly associated with exercise capacity. Peak VO₂ was not associated with the amount of myocardial fibrosis on CMR (mean of late gadolinium enhancement 12.25 ± 9.67%LV).

CONCLUSION

Decreased exercise capacity was associated with age, female sex, increased NT-proBNP level, and E/e' ratio on echocardiography. Hemodynamic changes and increased filling pressure on echocardiography should be monitored in this population for improved outcomes.

Late Gadolinium Enhancement Cardiac Magnetic Resonance Imaging: From Basic Concepts to Emerging Methods

BACKGROUND

 Late gadolinium enhancement (LGE) is a widely used cardiac magnetic resonance imaging (MRI) technique to diagnose a broad range of ischemic and non-ischemic cardiomyopathies. Since its development and validation against histology already more than two decades ago, the clinical utility of LGE and its span of applications have increased considerably.

METHODS

 In this review we will present the basic concepts of LGE imaging and its diagnostic and prognostic value, elaborate on recent developments and emerging methods, and finally discuss future prospects.

RESULTS

 Continuous developments in 3 D imaging methods, motion correction techniques, water/fat-separated imaging, dark-blood methods, and scar quantification improved the performance and further expanded the clinical utility of LGE imaging.

CONCLUSION

 LGE imaging is the current noninvasive reference standard for the assessment of myocardial viability. Improvements in spatial resolution, scar-to-blood contrast, and water/fat-separated imaging further strengthened its position.

KEY POINTS

  · LGE MRI is the reference standard for the noninvasive assessment of myocardial viability. · LGE MRI is used to diagnose a broad range of non-ischemic cardiomyopathies in everyday clinical practice.. · Improvements in spatial resolution and scar-to-blood contrast further strengthened its position. · Continuous developments improve its performance and further expand its clinical utility.

CITATION FORMAT

· Holtackers RJ, Emrich T, Botnar RM et al. Late Gadolinium Enhancement Cardiac Magnetic Resonance Imaging: From Basic Concepts to Emerging Methods. Fortschr Röntgenstr 2022; DOI: 10.1055/a-1718-4355.

Relationship Between Fragmented QRS Complex and Left Ventricular Fibrosis and Function in Patients With Danon Disease

Background

Fragmented QRS (f-QRS) complex on the surface ECG is a cardiac conduction abnormality that indicates myocardial scarring. The relationship between the f-QRS complex and cardiac status in patients with Danon disease (DD) remains unclear and will be explored in this study.

Methods

Patients with genetically confirmed DD and cardiac magnetic resonance imaging (CMR) examinations were recruited from multiple centers. The number of leads, pattern, score, and segmental distribution of the f-QRS complex were assessed by surface 12-lead ECG. Cardiac status, such as left ventricular (LV) volume, function, and extent of late gadolinium enhancement (LGE), was demonstrated by CMR. The segmental distribution of LGE was also assessed. Correlations between the f-QRS and cardiac status were assessed.

Results

Fifteen patients (14 men) with DD who underwent 12-lead ECG and CMR imaging were included. The f-QRS complex was documented in all patients (n = 15, 100%). Three patterns of f-QRS were found, with the notched R/S pattern (74%) being the most common, followed by fragmented QRS (16%) and various RSR' (11%). The fragmented QRS pattern showed an association with a higher level of myocardial fibrosis (LGE > 35%). The burden of f-QRS in each patient was assessed by the number of leads with f-QRS (median 7, range 2–12) and the f-QRS score (median 9, range 2–33). In the correlation analysis, the f-QRS score was positively correlated with LGE% (r = 0.726, p = 0.002), negatively correlated with LV ejection function (LVEF; r = −0.617, p = 0.014) as evaluated by CMR. In the local distribution, f-QRS score and LGE% were both predominant in the LV free wall but did not correlate well among the anterior, lateral, and inferior segments.

Conclusion

In this DD cohort, the quantitative f-QRS was correlated well with myocardial fibrosis burden and LV dysfunction in general. This finding suggests that f-QRS can be used as a simple screening tool to assess cardiac status in patients with DD.

The Relationship between Cardiac Magnetic Resonance-Assessed Replacement and Interstitial Fibrosis and Ventricular Arrhythmias in Hypertrophic Cardiomyopathy

Non-sustained ventricular tachycardia (nsVT) creates the electrical basis for sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM). We aimed to evaluate the relationship between interstitial fibrosis on cardiac magnetic resonance (CMR) and nsVT in HCM. A total of 50 HCM patients underwent CMR with a 3 T scanner to determine the presence of replacement fibrosis expressed by late gadolinium enhancement (LGE), and interstitial fibrosis expressed by native T₁, post-contrast T₁, and extracellular volume (ECV). The incidence of nsVT was assessed by Holter monitoring. We detected nsVT in 14 (28%) out of 50 HCM patients. Replacement fibrosis expressed by LGE was present in 37 (74%) patients and only showed a trend towards a differentiation between the groups with and without nsVT (p = 0.07). However, the extent of LGE was clearly higher in the nsVT group (3.8 ± 4.9% vs. 7.94 ± 4.5%, p = 0.002) and was an independent predictor of nsVT in a multivariable regression analysis (OR 1.2; 95%CI 1.02-1.4; p = 0.02). No relationship was observed between interstitial fibrosis and nsVT. To conclude, it was found that it is not the mere presence but the actual extent of LGE that determines the occurrence of nsVT in HCM patients; the role of interstitial fibrosis remains unclear.

Anatomical-MRI Correlations in Adults and Children with Hypertrophic Cardiomyopathy

Hypertrophic Cardiomyopathy (HCM) is the most frequent hereditary cardiovascular disease and the leading cause of sudden cardiac death in young individuals. Advancements in CMR imaging have allowed for earlier identification and more accurate prognosis of HCM. Interventions aimed at slowing or stopping the disease’s natural course may be developed in the future. CMR has been validated as a technique with high sensitivity and specificity, very few contraindications, a low risk of side effects, and is overall a good tool to be employed in the management of HCM patients. The goal of this review is to evaluate the magnetic resonance features of HCM, starting with distinct phenotypic variants of the disease and progressing to differential diagnoses of athlete’s heart, hypertension, and infiltrative cardiomyopathies. HCM in children has its own section in this review, with possible risk factors that are distinct from those in adults; delayed enhancement in children may play a role in risk stratification in HCM. Finally, a number of teaching points for general cardiologists who recommend CMR for patients with HCM will be presented.

Hypertrophic Cardiomyopathy: New Concepts and Therapies

Hypertrophic cardiomyopathy (HCM), a relatively common, globally distributed, and often inherited myocardial disorder, transformed over the last several years into a treatable condition with the emergence of effective management options that alter natural history at all ages. Now available are a matured risk stratification algorithm selecting patients for prophylactic implantable defibrillators that prevent arrhythmic sudden death; low-risk, high-benefit surgical myectomy to reverse progressive heart failure symptoms due to left ventricular outflow obstruction; anticoagulation prophylaxis to prevent atrial fibrillation-mediated embolic stroke; and heart transplant for refractory end-stage disease in the absence of obstruction. Those strategies have resulted in reduction of HCM-related morbidity and reduction of mortality to 0.5% per year.

Magnetic Resonance for Differential Diagnosis of Left Ventricular Hypertrophy: Diagnostic and Prognostic Implications

BACKGROUND

Left ventricular hypertrophy (LVH) may be due to different causes, ranging from benign secondary forms to severe cardiomyopathies. Transthoracic Echocardiography (TTE) and ECG are the first-level examinations for LVH diagnosis. Cardiac magnetic resonance (CMR) accurately defines LVH type, extent and severity.

OBJECTIVES

to evaluate the diagnostic and prognostic role of CMR in patients with TTE and/or ECG evidence of LVH.

METHODS

We performed CMR in 300 consecutive patients with echocardiographic and/or ECG signs of LVH.

RESULTS

Overall, 275 patients had TTE evidence of LVH, with initial suspicion of hypertrophic cardiomyopathy (HCM) in 132 (44%), cardiac amyloidosis in 41 (14%), hypertensive LVH in 48 (16%), aortic stenosis in 4 (1%), and undetermined LVH in 50 (16%). The initial echocardiographic diagnostic suspicion of LVH was confirmed in 172 patients (57.3%) and changed in 128 patients (42.7%, p < 0.0001): the diagnosis of HCM increased from 44% to 71% of patients; hypertensive and undetermined LVH decreased significantly (respectively to 4% and 5%). CMR allowed for a diagnosis in 41 out of 50 (82%) patients with undetermined LVH at TTE. CMR also identified HCM in 17 out of 25 patients with apparently normal echocardiography but with ECG criteria for LVH. Finally, the reclassification of the diagnosis by CMR was associated with a change in survival risk of patients: after CMR reclassification, no events occurred in patients with undetermined or hypertensive LVH.

CONCLUSIONS

CMR changed echocardiographic suspicion in almost half of patients with LVH. In the subgroup of patients with abnormal ECG, CMR identified LVH (particularly HCM) in 80% of patients. This study highlights the indication of CMR to better characterize the type, extent and severity of LVH detected at echocardiography and suspected with ECG.

Sudden cardiac death in cardiomyopathies: acting upon "acceptable" risk in the personalized medicine era

Patients with cardiomyopathies are confronted with the risk of sudden cardiac death (SCD) throughout their lifetime. Despite the fact that SCD is relatively rare, prognostic stratification is an integral part of physician-patient discussion, with the goal of risk modification and prevention. The current approach is based on a concept of "acceptable risk." However, there are intrinsic problems with an algorithm-based approach to risk management, magnified by the absence of robust evidence underlying clinical decision support tools, which can make high- versus low-risk classifications arbitrary. Strategies aimed at risk reduction range from selecting patients for an implantable cardioverter defibrillator (ICD) to disqualification from competitive sports. These clinical options, especially when implying the use of finite financial resources, are often delivered from the physician's perspective citing decision-making algorithms. When the burden of intervention-related risks or financial costs is deemed higher than an "acceptable risk" of SCD, the patient's perspective may not be appropriately considered. Designating a numeric threshold of "acceptable risk" has ethical implications. One could reasonably ask "acceptable to whom?" In an era when individual choice and autonomy are pillars of the physician-patient relationship, the subjective aspects of perceived risk should be acknowledged and be part of shared decision-making. This is particularly true when the lack of a strong scientific evidence base makes a dichotomous algorithm-driven approach suboptimal for unmitigated translation to clinical practice.

Correlation between markers of fibrosis and myocardial remodeling in patients with various course of hypertrophic cardiomyopathy

Aim. To assess the relationship between fibrosis markers and structural and functional parameters in patients with various types of hypertrophic cardiomyopathy (HCM).

Material and methods. This prospective comparative non-randomized study included 49 patients with HCM. Patients were divided into 3 groups according to the disease course: group 1  — stable course (n=12; men, 8 (67%), mean age ‒ 41±12 years); group 2 — progressive course (n=26; men, men, 16 (61%). mean age — 57±11 years); group 3 — patients with atrial fibrillation (AF) (n=11; men, 4 (36%), mean age — 63±6 years). Patients underwent standard clinical and paraclinical investigations. The levels of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinases-1 (TIMP-1) were determined in all patients using enzyme-linked immunosorbent assay in blood serum.

Results. In all patients with HCM, elevated levels of MMP-9 and TIMP-1 are noted compared to the reference values. In group 1, the MMP-9 level [Me (Q1; Q3)] was 226 (201;271) ng/ml; TIMP-1 — 410 (267;488) ng/ml; in group 2, the MMP-9 level was 236 (187;285) ng/ml; TIMP-1 — 421 (321;499) ng/ml. In the course with AF, the MMP-9 level was 260 (228;296) ng/ml, while TIMP-1 — 381,5 (305;466) ng/ml; no significant difference was revealed (p=0,59; p=0,90, respectively). A correlation was found between age and MMP-9 levels, as well as between MMP-9 levels and left atrial volume (p=0,034; p=0,035, respectively).

Conclusion. The high activity of matrix metalloproteinases and their tissue inhibitors reflects enhanced fibrosis and myocardial remodeling in HCM, which is especially characteristic of patients with AF.

 

The Role of Cardiovascular Magnetic Resonance Imaging in the Evaluation of Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disorder, affecting 1 out of 500 adults globally. It is a widely heterogeneous disorder characterized by a range of phenotypic expressions, and is most often identified by non-invasive imaging that includes echocardiography and cardiovascular magnetic resonance imaging (CMR). Within the last two decades, cardiac magnetic resonance imaging (MRI) has emerged as the defining tool for the characterization and prognostication of cardiomyopathies. With a higher image quality, spatial resolution, and the identification of morphological variants of HCM, CMR has become the gold standard imaging modality in the assessment of HCM. Moreover, it has been crucial in its management, as well as adding prognostic information that clinical history nor other imaging modalities may not provide. This literature review addresses the role and current applications of CMR, its capacity in evaluating HCM, and its limitations.

Multimodality Cardiac Imaging in Cardiomyopathies: From Diagnosis to Prognosis

Cardiomyopathies are a group of structural and/or functional myocardial disorders which encompasses hypertrophic, dilated, arrhythmogenic, restrictive, and other cardiomyopathies. Multimodality cardiac imaging techniques are the cornerstone of cardiomyopathy diagnosis; transthoracic echocardiography should be the first-line imaging modality due to its availability, and diagnosis should be confirmed by cardiovascular magnetic resonance, which will provide more accurate morphologic and functional information, as well as extensive tissue characterization. Multimodality cardiac imaging techniques are also essential in assessing the prognosis of patients with cardiomyopathies; left ventricular ejection fraction and late gadolinium enhancement are two of the main variables used for risk stratification, and they are incorporated into clinical practice guidelines. Finally, periodic testing with cardiac imaging techniques should also be performed due to the evolving and progressive natural history of most cardiomyopathies.

The Impact of Ischemia Assessed by Magnetic Resonance on Functional, Arrhythmic, and Imaging Features of Hypertrophic Cardiomyopathy

Aims: The aim of the study is to investigate the association between the degree of ischemia due to coronary microvascular dysfunction (CMD) and the left ventricular (LV) tissue characteristics, systolic performance, and clinical manifestations in hypertrophic cardiomyopathy (HCM).

Methods and Results: This prospective study enrolled 75 patients with HCM without obstructive epicardial coronary artery disease. Each patient underwent cardiovascular magnetic resonance (CMR) including parametric mapping, perfusion imaging during regadenoson-induced hyperemia, late gadolinium enhancement (LGE) and three-dimensional longitudinal, circumferential, and radial strains analysis. Electrocardiogram, 24-h Holter recording, and cardiopulmonary exercise testing (CPET) were performed to assess arrhythmias and functional capacity. In total, 47 (63%) patients were men with the mean age of 54.6 (14.8) years, 51 (68%) patients had non-obstructive HCM, maximum wall thickness (MWT) was 20.2 (4.6) mm, LV ejection fraction (LVEF) was 71.6 (8.3%), and ischemic burden was 22.5 (16.9%) of LV. Greater MWT was associated with the severity of ischemia (β-estimate:1.353, 95% CI:0.182; 2.523, p = 0.024). Ischemic burden was strongly associated with higher values of native T1 (β-estimate:9.018, 95% CI:4.721; 13.315, p < 0.001). The association between ischemia and LGE was significant in following subgroup analyses: MWT 15–20 mm (β-estimate:1.941, 95% CI:0.738; 3.143, p = 0.002), non-obstructive HCM (β-estimate:1.471, 95% CI:0.258; 2.683, p = 0.019), women (β-estimate:1.957, 95% CI:0.423; 3.492, p = 0.015) and age <40 years (β-estimate:4.874, 95% CI:1.155; 8.594, p = 0.016). Ischemia in ≥21% of LV was associated with LGE >15% (AUC 0.766, sensitivity 0.724, specificity 0.659). Ischemia was also associated with atrial fibrillation or flutter (AF/AFL) (OR-estimate:1.481, 95% CI:1.020; 2.152, p = 0.039), but no association was seen for non-sustained ventricular tachycardia. Ischemia was associated with shorter time to anaerobic threshold (β-estimate: −0.442, 95% CI: −0.860; −0.023, p = 0.039).

Conclusion: In HCM, ischemia associates with morphological markers of severity of disease, fibrosis, arrhythmia, and functional capacity.

Major Clinical Issues in Hypertrophic Cardiomyopathy

By actively implementing contemporary management strategies in hypertrophic cardiomyopathy, morbidity and mortality can be substantially reduced. In this review, we discuss the pathophysiology and management of the major clinical issues in hypertrophic cardiomyopathy, including sudden cardiac death, atrial fibrillation and thromboembolism, dynamic left ventricular outflow tract obstruction, and heart failure progression. Although echocardiography and cardiac magnetic resonance imaging currently play an essential and complementary role in the management of hypertrophic cardiomyopathy, further studies are needed to establish how developing techniques such as myocardial deformation and late gadolinium enhancement can provide better risk stratification and guide treatment.

Hypertrophic cardiomyopathy (HCM) is one of the most common inheritable cardiomyopathies. Contemporary management strategies, including the advent of implantable cardioverter-defibrillators and effective anticoagulation, have substantially improved the clinical course of HCM patients; however, the disease burden of HCM is still high in Korea. Sudden cardiac death (SCD), atrial fibrillation and thromboembolic risk, dynamic left ventricular outflow tract (LVOT) obstruction, and heart failure (HF) progression remain important issues in HCM. SCD in HCM can be effectively prevented with implantable cardioverter-defibrillators. However, appropriate patient selection is important for primary prevention, and the 5-year SCD risk score and the presence of major SCD risk factors should be considered. Anticoagulation should be initiated in all HCM patients with atrial fibrillation regardless of the CHA₂DS₂-VASc score, and non-vitamin K antagonist oral anticoagulants are the first option. Symptomatic dynamic LVOT obstruction is first treated medically with negative inotropes, and if symptoms persist, septal reduction therapy is considered. The recently approved myosin inhibitor mavacamten is promising. HF in HCM is usually related to diastolic dysfunction, while about 5% of HCM patients show reduced left ventricular ejection fraction <50%, also referred to as “end-stage” HCM. Myocardial fibrosis plays an important role in the progression to advanced HF in patients with HCM. Patients who do not respond to guideline-directed medical therapy can be considered for heart transplantation. The development of imaging techniques, such as myocardial deformation on echocardiography and late gadolinium enhancement on cardiac magnetic resonance, can provide better risk evaluation and decision-making for management strategies in HCM.

Risk factors of sudden cardiac death in hypertrophic cardiomyopathy

PURPOSE OF REVIEW

Hypertrophic cardiomyopathy (HCM) is one of the leading causes of sudden cardiac death (SCD) in younger people and athletes. It is crucial to identify the risk factors for SCD in individuals with HCM. This review, based on recent systematic literature studies, will focus on the risk factors for SCD in patients with HCM.

RECENT FINDINGS

An increasing number of studies have further explored the risk factors for SCD in patients with HCM, and new risk markers have emerged accordingly. In addition, more accurate SCD risk estimation and stratification methods have been proposed and continuously improved.

SUMMARY

The identification of independent risk factors for HCM-related SCD would likely contribute to risk stratification. However, it is difficult to predict SCD with absolute certainty, as the annual incidence of SCD in adult patients with HCM is approximately 1%. The review discusses the established risk factors, such as a family history of SCD, unexplained syncope and some new risk factors. Taken together, the findings of this review demonstrate that there is a need for further research on individual risk factors and that SCD risk stratification in HCM patients remains a clinical challenge.

Radiomics Analysis Derived From LGE-MRI Predict Sudden Cardiac Death in Participants With Hypertrophic Cardiomyopathy

Objectives: To identify significant radiomics features derived from late gadolinium enhancement (LGE) images in participants with hypertrophic cardiomyopathy (HCM) and assess their prognostic value in predicting sudden cardiac death (SCD) endpoint.

Method: The 157 radiomic features of 379 sequential participants with HCM who underwent cardiovascular magnetic resonance imaging (MRI) were extracted. CoxNet (Least Absolute Shrinkage and Selection Operator (LASSO) and Elastic Net) and Random Forest models were applied to optimize feature selection for the SCD risk prediction and cross-validation was performed.

Results: During a median follow-up of 29 months (interquartile range, 20–42 months), 27 participants with HCM experienced SCD events. Cox analysis revealed that two selected features, local binary patterns (LBP) (19) (hazard ratio (HR), 1.028, 95% CI: 1.032–1.134; P = 0.001) and Moment (1) (HR, 1.212, 95%CI: 1.032–1.423; P = 0.02) provided significant prognostic value to predict the SCD endpoints after adjustment for the clinical risk predictors and late gadolinium enhancement. Furthermore, the univariately significant risk predictor was improved by the addition of the selected radiomics features, LBP (19) and Moment (1), to predict SCD events (P < 0.05).

Conclusion: The radiomics features of LBP (19) and Moment (1) extracted from LGE images, reflecting scar heterogeneity, have independent prognostic value in identifying high SCD risk patients with HCM.

EACVI survey on hypertrophic cardiomyopathy

AIMS

The European Association of Cardiovascular Imaging (EACVI) Scientific Initiatives Committee performed a global survey to evaluate current practice for the assessment and management of patients with hypertrophic cardiomyopathy (HCM).

METHODS AND RESULTS

A total of 213 centres from 38 different countries (87% European) responded to the survey. One hundred twenty-one (57%) centres followed HCM patients in a general cardiology outpatient clinic and 85 (40%) centres in a specialized HCM/cardiomyopathy clinic. While echocardiography was the primary imaging modality, cardiovascular magnetic resonance (CMR) has become an important complementary tool. Cardiac anatomy, left ventricular (LV) systolic, and diastolic function were assessed according to current European guidelines and recommendations. To evaluate LV obstruction, 49% of the centres performed bedside provocation manoeuvres in every patient and 55% of the centres used exercise stress echocardiography. The majority of centres used the 5-year risk assessment of sudden cardiac death (SCD) calculated with the HCM Risk-SCD score. However, 34% of the centres also used extensive non-infarct late gadolinium enhancement on CMR and 27% the presence of LV apical aneurysm to help select patients for primary prevention implantable cardioverter-defibrillator therapy. Ninety-nine percent of the responding centres performed regular imaging follow-up of HCM patients.

CONCLUSION

Most centres followed European guidelines and recommendations for the diagnosis and management of patients with HCM. The importance of bedside provocation manoeuvres and exercise stress echocardiography to diagnose LV outflow obstruction requires emphasis. Additional risk markers for SCD are used in many centres and might indicate the need for an update of current European recommendations.

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.

Importance of Newer Cardiac Magnetic Resonance-Based Risk Markers for Sudden Death Prevention in Hypertrophic Cardiomyopathy:An International Multicenter Study

BACKGROUND

The sudden death (SD) risk stratification algorithm in hypertrophic cardiomyopathy (HCM) has evolved, underscored recently by novel cardiac magnetic resonance (CMR)-based risk markers: LV apical aneurysm, extensive late gadolinium enhancement and end-stage with systolic dysfunction, incorporated into 2020 AHA/ACC HCM Guidelines.

OBJECTIVE

Assess the specific impact of newer predominantly CMR-based risk markers in a large multicenter HCM population that underwent primary prevention ICD implants METHODS: Longitudinal study of 1149 consecutive HCM patients from 6 North American and European HCM centers prospectively judged to be at high SD risk based on ≥ 1 AHA/ACC individual risk markers and prophylactically implanted with ICDs. ESC risk score was retrospectively analyzed with respect to the known clinical outcome.

RESULTS

Of 1149 patients with ICDs, 162 (14%) experienced device therapy terminating VT/VF 4.6 ± 4.2 years after implant. CMR-based markers solely or in combination led to ICD implantation in 49 of the 162 patients (30%) experiencing device-therapy. Particularly low ESC scores (<4%/5-years) would have excluded an ESC-ICD recommendation for 67 patients who nevertheless experienced appropriate ICD therapy included 26 with the CMR-based risk markers not part of the ESC formula.

CONCLUSION

The identification and incorporation of novel guideline-supported CMR-based risk markers enhances selection of HCM patients for SD prevention with ICDs. Absence of CMR-based markers from the ESC risk score in part accounts for it not identifying many HCM patients with SD events. These data support inclusion of CMR as a routine part of HCM patient evaluation and risk stratification.

Prognostic role of global longitudinal strain by feature tracking in patients with hypertrophic cardiomyopathy: The STRAIN-HCM study

BACKGROUND

The assessment of myocardial fiber deformation with cardiac magnetic resonance feature tracking (CMR-FT) has shown to be promising in terms of prognostic information in several structural heart diseases. However, little is known about its role in hypertrophic cardiomyopathy (HCM). Aims of the present study were: 1) to assess the prognostic role of CMR-FT derived strain parameters in patients with HCM.

METHODS

CMR was performed in 130 consecutive HCM patients (93 males, mean age (54 ± 17 years) with an estimated 5-year risk of sudden cardiac death (SCD) <6% according to the HCM Risk-SCD calculator. 2D- and 3D-Global Radial (GRS), Longitudinal (GLS) and Circumferential (GCS) Strain was evaluated by FT analysis. The primary outcome of the study was a composite of major adverse cardiac events (MACE) including SCD, resuscitated cardiac arrest due to ventricular fibrillation (VF) or hemodynamically unstable ventricular tachycardia (VT), and hospitalization for heart failure.

RESULTS

After a median follow-up of 51.7 (37.1-68.8) months, 4 (3%) patients died (all of them suffered from SCD) and 36 (28%) were hospitalized for heart failure. After multivariable adjustment for clinical and imaging covariates, among all strain parameters, only GLS remained a significant independent predictor of outcome events in both the model including 2D strain (HR 1.12, 95% CI 1.03-1.23, p = 0.01) and the model including 3D strain (HR 1.14, 95% CI 1.01-1.30, p = 0.04). The addition of 2D-GLS into the model with clinical and imaging predictors resulted in a significant increase in the C-statistic (from 0.48 to 0.65, p = 0.03).

CONCLUSION

CMR-FT derived GLS is a powerful independent predictor of MACE in patients with HCM, incremental to common clinical and CMR risk factors including left ventricular ejection fraction and late gadolinium enhancement.

Mean Scar Entropy by Late Gadolinium Enhancement Cardiac Magnetic Resonance Is Associated With Ventricular Arrhythmias Events in Hypertrophic Cardiomyopathy

Background: Ventricular arrhythmias are associated with sudden cardiac death (SCD) in hypertrophic cardiomyopathy (HCM). Previous studies have found the late gadolinium enhancement (LGE) on cardiac magnetic resonance (CMR) was independently associated with ventricular arrhythmia (VA) in HCM. The risk stratification of VA remains complex and LGE is present in the majority of HCM patients. This study was conducted to determine whether the scar heterogeneity from LGE-derived entropy is associated with the VAs in HCM patients.

Materials and Methods: Sixty-eight HCM patients with scarring were retrospectively enrolled and divided into VA (31 patients) and non-VA (37 patients) groups. The left ventricular ejection fraction (LVEF) and percentage of the LGE (% LGE) were evaluated. The scar heterogeneity was quantified by the entropy within the scar and left ventricular (LV) myocardium.

Results: Multivariate analyses showed that a higher scar [hazard ratio (HR) 2.682; 95% CI: 1.022–7.037; p = 0.039] was independently associated with VA, after the adjustment for the LVEF, %LGE, LV maximal wall thickness (MWT), and left atrium (LA) diameter.

Conclusion: Scar entropy and %LGE are both independent risk indicators of VA. A high scar entropy may indicate an arrhythmogenic scar, an identification of which may have value for the clinical status assessment of VAs in HCM patients.

Microvolt QRS Alternans in Hypertrophic Cardiomyopathy: A Novel Risk Marker of Late Ventricular Arrhythmias

Background

Unlike T‐wave alternans (TWA), the relation between QRS alternans (QRSA) and ventricular arrhythmia (VA) risk has not been evaluated in hypertrophic cardiomyopathy (HCM). We assessed microvolt QRSA/TWA in relation to HCM risk factors and late VA outcomes in HCM.

Methods and Results

Prospectively enrolled patients with HCM (n=130) with prophylactic implantable cardioverter‐defibrillators underwent digital 12‐lead ECG recordings during ventricular pacing (100–120 beats/min). QRSA/TWA was quantified using the spectral method. Patients were categorized as QRSA+ and/or TWA+ if sustained alternans was present in ≥2 precordial leads. The VA end point was appropriate implantable cardioverter‐defibrillator therapy over 5 years of follow‐up. QRSA+ and TWA+ occurred together in 28% of patients and alone in 7% and 7% of patients, respectively. QRSA magnitude increased with pacing rate (1.9±0.6 versus 6.2±2.0 µV; P=0.006). Left ventricular thickness was greater in QRSA+ than in QRSA− patients (22±7 versus 20±6 mm; P=0.035). Over 5 years follow‐up, 17% of patients had VA. The annual VA rate was greater in QRSA+ versus QRSA− patients (5.8% versus 2.0%; P=0.006), with the QRSA+/TWA− subgroup having the greatest rate (13.3% versus 2.6%; P<0.001). In those with <2 risk factors, QRSA− patients had a low annual VA rate compared QRSA+ patients (0.58% versus 7.1%; P=0.001). Separate Cox models revealed QRSA+ (hazard ratio [HR], 2.9 [95% CI, 1.2–7.0]; P=0.019) and QRSA+/TWA− (HR, 7.9 [95% CI, 2.9–21.7]; P<0.001) as the most significant VA predictors. TWA and HCM risk factors did not predict VA.

Conclusions

In HCM, microvolt QRSA is a novel, rate‐dependent phenomenon that can exist without TWA and is associated with greater left ventricular thickness. QRSA increases VA risk 3‐fold in all patients, whereas the absence of QRSA confers low VA risk in patients with <2 risk factors.

Registration

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02560844.

Advanced cardiac imaging in athlete's heart: unravelling the grey zone between physiologic adaptation and pathology

Over the last decades, interest toward athlete's heart has progressively increased, leading to improve the knowledge on exercise-induced heart modifications. Sport may act as a trigger for life-threatening arrhythmias in patients with structural or electrical abnormalities, hence requiring to improve the diagnostic capability to differentiate physiological from pathological remodeling. Pathological alterations are often subtle at the initial stages; therefore, the challenge is to promptly identify athletes at risk of sudden cardiac death during the pre-participation screening protocols. Advanced imaging modalities such as coronary computed tomography angiography (CCTA) and cardiac magnetic resonance (CMR) can non-invasively depict coronary vessels and provide a deep morpho-functional and structural characterization of the myocardium, in order to rule out pathological life threatening alterations, which may overlap with athletes' heart remodeling. The purpose of the present narrative review is to provide an overview of most frequent diagnostic challenges, defining the boundaries between athlete's heart remodeling and pathological structural alteration with a focus on the role and importance of CCTA and CMR.

Ventricular arrhythmia management in patients with genetic cardiomyopathies

Genetic cardiomyopathies are associated with increased risk for cardiac arrhythmias and sudden cardiac death. The management of ventricular arrhythmias (VAs) in patients with these conditions can be nuanced due to particular disease-based considerations, yet data specifically addressing management in these patients are limited. Here we describe the current evidence-based approach to the management of ventricular rhythm disorders in patients with genetic forms of cardiomyopathy, namely, hypertrophic cardiomyopathy, arrhythmogenic cardiomyopathy, left ventricular noncompaction, and Brugada syndrome, including recommendations from consensus guideline statements when available.

Non-pharmaceutical Interventions for Hypertrophic Cardiomyopathy: A Mini Review

Hypertrophic cardiomyopathy is an inherited cardiovascular disease, and 70% of patients have left ventricular outflow tract obstruction. Ventricular septal myectomy has been the gold standard treatment for most patients with refractory symptoms. Due to higher mortality associated with medical facilities with less experience, alcohol septal ablation has been accepted as an alternative to conventional surgical myectomy. It offers lower all-cause in-hospital complications and mortality, which could be potentially more preferable for patients with serious comorbidities. In recent years, radiofrequency ablation, providing another option with reproducibility and a low risk of permanent atrioventricular block, has become an effective invasive treatment to relieve left ventricular outflow tract obstruction. Moreover, substantial progress has been made in gene therapy for hypertrophic cardiomyopathy. The principal objective of this review is to present recent advances in non-pharmaceutical interventions in hypertrophic cardiomyopathy.

Patterns of Replacement Fibrosis in Hypertrophic Cardiomyopathy

Background Myocardial replacement fibrosis is one of the major histologic features of hypertrophic cardiomyopathy (HCM), but its characteristics have not been well delineated. Purpose To clarify the characteristics of replacement fibrosis in HCM and to evaluate the prognostic value of the regional extent of fibrosis. Materials and Methods This prospective study evaluated participants with HCM who underwent contrast-enhanced cardiac MRI from March 2011 to April 2019. For each participant, global and 16-segment extent of late gadolinium enhancement (LGE) in the left ventricle (LV) at cardiac MRI was analyzed. The primary end point was all-cause death. Results Among the 798 study participants enrolled (median age, 49 years [interquartile range {IQR}: 38-59 years]; 508 men), 588 (74%) underwent whole-exome sequencing. Thirty-five participants (4%) experienced death from any cause during a median follow-up of 2.9 years (IQR: 1.5-4.7 years). Spearman analysis showed weak correlations between the extent of LGE and wall thickness (LGE of global LV and maximal LV wall thickness, r = 0.35 [P < .001]; LGE and thickness of septum, r = 0.30 [P < .001]). In the 16-segment model, the distribution of LGE was visually inhomogeneous and higher in the basal anterior, basal septal, midanterior, and midseptal regions (P < .001). This similar distribution of LGE was observed in participants with asymmetric septal hypertrophy, those with apical HCM, participants positive for mutation and those negative for mutation, and participants with MYH7 and MYBPC3 mutations. Cox analysis indicated that both the global extent of LGE (adjusted hazard ratio = 1.68 per 10% increase in LGE; P < .001) and the regional extent of LGE (ie, basal, midventricular, and apical regions of LV when on the short-axis view; septum, anterior free wall, inferior free wall, and lateral free wall when on the long-axis view) were associated with adverse outcomes. Conclusion In hypertrophic cardiomyopathy, myocardial replacement fibrosis weakly correlated with hypertrophy, was inhomogeneous and asymmetric, and was predominantly distributed in the interventricular septal wall and anterior free wall at the basal and mid levels. Greater extent of fibrosis was associated with poor prognosis, regardless of its location in the left ventricle. © RSNA, 2021 See also the editorial by Hanneman in this issue.

Prognostic Value of Transthoracic Doppler Echocardiography Coronary Flow Velocity Reserve in Patients With Asymmetric Hypertrophic Cardiomyopathy

Background

Microvascular dysfunction might be a major determinant of clinical deterioration and outcome in patients with hypertrophic cardiomyopathy (HCM). However, long‐term prognostic value of transthoracic Doppler echocardiography (TDE) coronary flow velocity reserve (CFVR) on clinical outcome is uncertain in HCM patients. Therefore, the aim of our study was to assess long‐term prognostic value of CFVR on clinical outcome in HCM population.

Methods and Results

We prospectively included 150 HCM patients (82 women; mean age 48±15 years). Patients’ clinical characteristics, echocardiographic and CFVR findings (both for left anterior descending [LAD] and posterior descending artery [PD]), were assessed in all patients. The primary outcome was a composite of: HCM related death, heart failure requiring hospitalization, sustained ventricular tachycardia and ischemic stroke. Patients were stratified into 2 subgroups depending on CFVR LAD value: Group 1 (CFVR LAD>2, [n=87]) and Group 2 (CFVR LAD≤2, [n=63]). During a median follow‐up of 88 months, 41/150 (27.3%) patients had adverse cardiac events. In Group 1, there were 8/87 (9.2%), whereas in Group 2 there were 33/63 (52.4%, P<0.001 vs. Group 1) adverse cardiac events. By Kaplan‐Meier analysis, patients with preserved CFVR LAD had significantly higher cumulative event‐free survival rate compared to patients with impaired CFVR LAD (96.4% and 90.9% versus 66.9% and 40.0%, at 5 and 8 years, respectively: log‐rank 37.2, P<0.001). Multivariable analysis identified only CFVR LAD≤2 as an independent predictor for adverse cardiac outcome (HR 6.54; 95% CI 2.83–16.30, P<0.001), while CFVR PD was not significantly associated with outcome.

Conclusions

In patients with HCM, impaired CFVR LAD (≤2) is a strong, independent predictor of adverse cardiac outcome. When the aim of testing is HCM risk stratification and CFVR LAD data are available, the evaluation of CFVR PD is redundant.

Risk stratification in cardiomyopathies (dilated, hypertrophic, and arrhythmogenic cardiomyopathy) by cardiac magnetic resonance imaging

Cardiac magnetic resonance imaging (CMR) is a non-invasive, multiplanar, and high spatial resolution imaging technique, which represents the current gold standard for the evaluation of biventricular volumes and function. Furthermore, unlike other methods, it has the great advantage of characterizing the myocardial tissue by identifying the presence of alterations, such as oedema and focal and diffuse fibrosis. In particular, the late gadolinium enhancement technique makes it possible to identify areas of focal fibrosis that often constitute the substrate for the triggering of threatening ventricular arrhythmias at the basis of sudden cardiac death. For this reason, the use of CMR in the study of cardiomyopathies has become of primary importance, both for the differential diagnosis and for patient risk stratification. In this brief review, the ability of CMR in prognostic stratification of patients with dilated, hypertrophic, and arrhythmogenic cardiomyopathy will be analysed. In particular, the role of CMR in the prediction of arrhythmic risk and in the decision-making process for the implantation of a cardiac defibrillator will be examined.

Clinical, echocardiographic and cardiac MRI predictors of outcomes in patients with apical hypertrophic cardiomyopathy

Recent studies have found that some adverse cardiovascular events could also occur in patients with apical hypertrophic cardiomyopathy (ApHCM), which is different with previous studies suggesting benign nature of this condition. Therefore, the present study aimed to observe the clinical prognosis of ApHCM and to identify the predictors of poor prognosis in clinical, echocardiography and cardiac magnetic resonance (CMR). A total of 126 ApHCM patients with both echocardiography and CMR were identified retrospectively from January 2008 to December 2018. Adverse clinical events were defined as a composite of cardiac death, progressive heart failure, myocardial infarction, thromboembolic stroke, appropriate implantable cardioverter-defibrillator (ICD) interventions for ventricular tachycardia or ventricular fibrillation, and new-onset atrial fibrillation (AF). During a mean follow-up of 96.8 ± 36.0 months, clinical events were observed in 34 (27.0%) patients. As compared with patients without clinical events, patients with clinical events were older and had a higher incidence of heart failure. Moreover, patients with clinical events had a higher incidence of non-sustained ventricular tachycardia (NSVT) and had larger left atrial volume index (LAVI), thicker apical thickness, lower peak systolic mitral annular velocity (S') than those without clinical events. In addition, late gadolinium enhancement (LGE) in CMR were more frequently observed in patients with clinical events. Five predictors of poor prognosis were identified: age ≥ 55 years, LAVI ≥ 36.7 ml/m², S' ≤ 6.7 cm/s, NSVT and LGE. ApHCM was not as benign as expected. Age ≥ 55 years, LAVI ≥ 36.7 ml/m², S' ≤ 6.7 cm/s along with NSVT and LGE were independent predictors for poor prognosis of ApHCM.

Targeted exome analysis of Russian patients with hypertrophic cardiomyopathy

Background

Hypertrophic cardiomyopathy (HCM), described as the presence of hypertrophy of left ventricular, is the most prevalent heritable cardiovascular disease with predominantly an autosomal dominant type of inheritance. However, pathogenic alleles are not identified in at least 25% of patients with HCM, and the spectrum of pathogenic variants that contribute to the development of HCM in Russia has not been fully described. Therefore, the goal of our study was to identify genetic variants associated with the etiopathogenesis of HCM in Russian patients.

Methods

The study cohort included 98 unrelated adult patients with HCM. We performed targeted exome sequencing, an analysis using various algorithms for prediction of the impact of variants on protein structure and the prediction of pathogenicity using ACMG Guidelines.

Results

The frequency of pathogenic and likely pathogenic variants in all HCM‐related genes was 8% in our patients. We also identified 20 variants of uncertain significance in all HCM‐related genes.

Conclusions

The prevalence of individual pathogenic variants in HCM‐related genes in Russian population appears to be lower than in general European population, which could be explained by ethnic features of Russian population, age characteristics of our sample, or unidentified pathogenic variants in genes previously not linked with HCM.

Supplementary role of left ventricular global longitudinal strain for predicting sudden cardiac death in hypertrophic cardiomyopathy

AIMS

We investigated the prognostic role of left ventricular global longitudinal strain (LV-GLS) and its incremental value to established risk models for predicting sudden cardiac death (SCD) in patients with hypertrophic cardiomyopathy (HCM).

METHODS AND RESULTS

LV-GLS was measured with vendor-independent software at a core laboratory in a cohort of 835 patients with HCM (aged 56.3 ± 12.2 years) followed-up for a median of 6.4 years. The primary endpoint was SCD events, including appropriate defibrillator therapy, within 5 years after the initial evaluation. The secondary endpoint was a composite of SCD events, heart failure admission, heart transplantation, and all-cause mortality. Twenty (2.4%) and 85 (10.2%) patients experienced the primary and secondary endpoints, respectively. Lower absolute LV-GLS quartiles, especially those worse than the median (-15.0%), were associated with progressively higher SCD event rates (P = 0.004). LV-GLS was associated with an increased risk for the primary endpoint, independent of the LV ejection fraction, apical aneurysm, and 2014 European Society of Cardiology (ESC) risk score [adjusted hazard ratio (aHR) 1.14, 95% confidence interval (CI) 1.02-1.28] or 2011 American College of Cardiology/American Heart Association (ACC/AHA) risk factors (aHR 1.18, 95% CI 1.05-1.32). LV-GLS was also associated with a higher risk for the composite secondary endpoint (aHR 1.06, 95% CI 1.01-1.12). The addition of LV-GLS enhanced the performance of the ESC risk score (C-statistic 0.756 vs. 0.842, P = 0.007) and the 2011 ACC/AHA risk factor strategy (C-statistic 0.743 vs. 0.814, P = 0.007) for predicting SCD.

CONCLUSION

LV-GLS is an important prognosticator in patients with HCM and provides additional information to established risk stratification strategies for predicting SCD.

Myocardial extracellular volume by T1 mapping: a new marker of arrhythmia in mitral valve prolapse

OBJECTIVES

We aimed to evaluate the relationship between mitral annular disjunction (MAD) severity and myocardial interstitial fibrosis at the left ventricular (LV) base in patients with mitral valve prolapse (MVP), and to assess the association between severity of interstitial fibrosis and the occurrence of ventricular arrhythmic events.

BACKGROUND

In MVP, MAD has been associated with myocardial replacement fibrosis and arrhythmia, but the importance of interstitial fibrosis remains unknown.

METHODS

In this retrospective study, 30 patients with MVP and MAD (MVP-MAD) underwent cardiovascular magnetic resonance (CMR) with assessment of MAD length, late gadolinium enhancement (LGE), and basal segments myocardial extracellular volume (ECVsyn). The control group included 14 patients with mitral regurgitation (MR) but no MAD (MR-NoMAD) and 10 patients with normal CMR (NoMR-NoMAD). Fifteen MVP-MAD patients underwent 24 h-Holter monitoring.

RESULTS

LGE was observed in 47% of MVP-MAD patients and was absent in all controls. ECVsyn was higher in MVP-MAD (30 ± 3% vs 24 ± 3% MR-NoMAD, p < 0.001 and vs 24 ± 2% NoMR-NoMAD, p < 0.001), even in MVP-MAD patients without LGE (29 ± 3% vs 24 ± 3%, p < 0.001 and vs 24 ± 2%, p < 0.001, respectively). MAD length correlated with ECVsyn (rho = 0.61, p < 0.001), but not with LGE extent. Four patients had history of out-of-hospital cardiac arrest; LGE and ECVsyn were equally performant to identify those high-risk patients, area under the receiver operating characteristic (ROC) curve 0.81 vs 0.83, p = 0.84). Among patients with Holter, 87% had complex ventricular arrhythmia. ECVsyn was above the cut-off value in all while only 53% had LGE.

CONCLUSION

Increase in ECVsyn, a marker of interstitial fibrosis, occurs in MVP-MAD even in the absence of LGE, and was correlated with MAD length and increased risk of out-of-hospital cardiac arrest. ECV should be includedin the CMR examination of MVP patients in an effort to better assess fibrous remodelling as it may provide additional value beyond the assessment of LGE in the arrhythmic risk stratification.

Validation of the 2020 AHA/ACC Risk Stratification for Sudden Cardiac Death in Chinese Patients With Hypertrophic Cardiomyopathy

Background: Sudden cardiac death (SCD) is a common cause of death in hypertrophic cardiomyopathy (HCM), but identification of patients at a high risk of SCD is challenging. The study aimed to validate the three SCD risk stratifications recommended by the 2011 ACCF/AHA guideline, the 2014 ESC guideline, and the 2020 AHA/ACC guideline in Chinese HCM patients.

Methods: The study population consisted of a consecutive cohort of 511 patients with HCM without a history of SCD event. The endpoint was a composite of SCD or an equivalent event (appropriate implantable cardioverter defibrillator therapy or successful resuscitation after cardiac arrest).

Results: During a follow-up of 4.7 ± 1.7 years, 15 patients (2.9%) reached the SCD endpoint and 12 (2.3%) were protected by implantable cardioverter defibrillator for primary prevention. A total of 13 (2.8%) patients experiencing SCD events were misclassified as low-risk patients by the 2011 ACCF/AHA guideline, 12 (2.3%) by the 2014 ESC model, and 7 (1.6%) by the 2020 AHA/ACC guideline. The SCD risk stratification in the 2020 AHA/ACC guideline showed greater area under the curve (0.71; 95% CI 0.56–0.87, p < 0.001) than the one in the 2011 ACCF/AHA guideline (0.52; 95% CI 0.37–0.67, p = 0.76) and 2014 ESC guideline (0.68; 95% CI 0.54–0.81, p = 0.02).

Conclusion: The SCD risk stratification recommended by the 2020 AHA/ACC guideline showed a better discrimination than previous stratifications in Chinese patients with HCM. A larger multicenter, independent, and prospective study with long-term follow-up would be warranted to validate our result.

Looking for the Right Diagnosis? Cardiovascular Magnetic Resonance Imaging Can Help Differentiate Cardiomyopathies

Differentiating cardiomyopathies is a common clinical quandary in cardiology. Getting the right diagnosis is important for guiding patient management and providing prognosis. Incorrect or uncertain diagnoses can lead to further unnecessary investigations and/or treatment decisions applied inappropriately, which can have consequences for both the patient and health care costs. Cardiovascular magnetic resonance (CMR) imaging offers strength here due to its precision and breadth in assessing cardiac function and tissue characterisation. This review aims to raise awareness among cardiologists and physicians of the important insights provided by CMR-insights that can improve diagnosis and guide management, as well as aid in risk stratification, in different cardiomyopathies.