Evaluation of apical subtype of hypertrophic cardiomyopathy using cardiac magnetic resonance imaging with gadolinium enhancement

Apical hypertrophic cardiomyopathy: pathophysiology, diagnosis and management

Since the first description of apical hypertrophic cardiomyopathy (ApHCM) in 1976, contrasting information from all over the world has emerged regarding the natural history of the disease. However, the recommended guidelines on hypertrophic cardiomyopathy (HCM) pay a cursory reference to ApHCM, without ApHCM-specific recommendations to guide the diagnosis and management. In addition, cardiologists may not be aware of certain aspects that are specific to this disease subtype, and a robust understanding of specific disease features can facilitate recognition and timely diagnosis. Therefore, the review covers the incidence, pathogenesis, and characteristics of ApHCM and imaging methods. Echocardiography and cardiovascular magnetic resonance imaging (CMR) are the most commonly used imaging methods. Moreover, this review presents the management strategies of this heterogeneous clinical entity. In this review, we introduce a novel transapical beating-heart septal myectomy procedure for ApHCM patients with a promising short-time result.

Apical hypertrophic cardiomyopathy with subendocardial late gadolinium enhancement in an adolescent

A 17-year-old boy with a history of dyspnea attacks and chest pain was referred to our paediatric cardiology department. Electrocardiogram at presentation showed T-wave inversion in the inferior leads. Cardiovascular magnetic resonance imaging revealed the rare diagnosis of apical hypertrophic cardiomyopathy with subendocardial late gadolinium enhancement, missed by echocardiography.

Clinical Outcomes of Myocardial Bridging versus No Myocardial Bridging in Patients with Apical Hypertrophic Cardiomyopathy

Objective: To determine the prevalence and clinical effects of myocardial bridging (MB) in patients with apical hypertrophic cardiomyopathy (AHCM). Methods: Angiograms from 212 AHCM patients were reviewed to identify MB. The patients were classified into 2 groups: AHCM with and AHCM without MB. We reviewed patient records on cardiovascular (CV) risk factors, symptoms, CV events, and CV mortality. Results: In all, 60 patients with MB and 100 without MB were included. Rates of angina (61.7 vs. 40%; p = 0.008), mimicking non-ST-segment elevation myocardial infarction (15 vs. 3%, p = 0.013), and Canadian Cardiovascular Society class III/IV angina (18.3 vs. 4%; p = 0.003) were higher in patients with MB than in those without. Mean follow-up periods (65.5 ± 50.5 vs. 64.4 ± 43.6 months, p = 0.378) and CV mortality (3.3 vs. 1%; p = 0.652) were similar in the 2 groups. Kaplan-Meier estimates demonstrated that CV event-free survival rates were lower in patients with MB than in those without (71.7 vs. 88%; p = 0.022). MB, late gadolinium enhancement, and female sex were independent risk factors for CV events in a multivariate Cox regression analysis adjusted for other risk factors. Conclusion: More serious symptoms and a higher risk of CV events were observed in AHCM patients with MB than in those without MB. CV mortality was similar in these 2 groups.

Incidental spade-shaped FDG uptake in the left ventricular apex suggests apical hypertrophic cardiomyopathy

PURPOSE

Apical wall thickening with an "ace-of-spades" configuration is a unique sign of apical hypertrophic cardiomyopathy (AHCM). We investigated spade-shaped FDG uptake around the left ventricular apex (SSUA) incidentally found in routine oncological FDG PET.

METHODS

Cases showing SSUA were selected based on retrospective review. The pattern or intensity of SSUA was compared with the results of electrocardiogram (ECG), echocardiography, and stress myocardial perfusion SPECT. The diagnosis of ACHM was based on the presence of giant negative T wave in ECG, thickness of spade-shaped hypertrophy in the apex in echocardiography, and increased tracer uptake in the apex in rest SPECT.

RESULTS

Among the 34 patients in 36 PET scans showing SSUA, SSUA was weak in 17 and intense in 17. There were isolated SSUA (n = 29) and SSUA with diffuse or other focal left ventricular uptake (n = 5). Three patients with the latter uptake pattern turned out to have coexistence of AHCM and asymmetric septal hypertrophy. Of the 16 SSUA-positive patients who underwent echocardiography, 13 (81%) were diagnosed as AHCM and the remaining 3 were regarded as borderline AHCM (apical wall thickness, 14-15 mm). There were 16 patients with SSUA who also underwent PET scans after the study period among which 11 (69%) had persistent SSUA in the follow-up PET. In the remaining 5, follow-up PET scans showed diffuse left ventricular uptake and SSUA was barely visible. The intensity of SSUA was significantly or marginally associated with giant negative T wave (p < 0.01), apical asynergy (p = 0.08), and impaired coronary flow reserve (p < 0.05). There were no other factors correlated with the pattern or intensity of SSUA.

CONCLUSION

SSUA incidentally found in oncological FDG PET appeared to be associated with AHCM, especially in ischemic conditions. The moderate repeatability of SSUA was probably due to obscurity by physiological uptake.

Hypertrophic obstructive cardiomyopathy

Hypertrophic obstructive cardiomyopathy is an inherited myocardial disease defined by cardiac hypertrophy (wall thickness ≥15 mm) that is not explained by abnormal loading conditions, and left ventricular obstruction greater than or equal to 30 mm Hg. Typical symptoms include dyspnoea, chest pain, palpitations, and syncope. The diagnosis is usually suspected on clinical examination and confirmed by imaging. Some patients are at increased risk of sudden cardiac death, heart failure, and atrial fibrillation. Patients with an increased risk of sudden cardiac death undergo cardioverter-defibrillator implantation; in patients with severe symptoms related to ventricular obstruction, septal reduction therapy (myectomy or alcohol septal ablation) is recommended. Life-long anticoagulation is indicated after the first episode of atrial fibrillation.

The clinical features, outcomes and genetic characteristics of hypertrophic cardiomyopathy patients with severe right ventricular hypertrophy

Introduction

Severe right ventricular hypertrophy (SRVH) is a rare phenotype in hypertrophic cardiomyopathy (HCM) for which limited information is available. This study was undertaken to investigate the clinical, prognostic and genetic characteristics of HCM patients with SRVH.

Methods

HCM with SRVH was defined as HCM with a maximum right ventricular wall thickness ≥10 mm. Whole-genome sequencing (WGS) was performed in HCM patients with SRVH. Multivariate Cox proportional hazards regression models were used to identify risk factors for cardiac death and events in HCM with SRVH. Patients with apical hypertrophic cardiomyopathy (ApHCM) were selected as a comparison group. The clinical features and outcomes of 34 HCM patients with SRVH and 273 ApHCM patients were compared.

Results

Compared with the ApHCM group, the HCM with SRVH group included younger patients and a higher proportion of female patients and also displayed higher cardiovascular morbidity and mortality. The multivariate Cox proportional hazards regression models identified 2 independent predictors of cardiovascular death in HCM patients with SRVH, a New York Heart Association class ≥III (hazard ratio [HR] = 8.7, 95% confidence interval (CI): 1.43-52.87, p = 0.019) and an age at the time of HCM diagnosis ≤18 (HR = 5.5, 95% CI: 1.24-28.36, p = 0.026). Among the 11 HCM patients with SRVH who underwent WGS, 10 (90.9%) were identified as carriers of at least one specific sarcomere gene mutation. MYH7 and TTN mutations were the most common sarcomere mutations noted in this study. Two or more HCM-related gene mutations were observed in 9 (82%) patients, and mutations in either other cardiomyopathy-related genes or ion-channel disease-related genes were found in 8 (73%) patients.

Conclusions

HCM patients with SRVH were characterized by poor clinical outcomes and the presentation of multiple gene mutations.

Hypertrophic Cardiomyopathy from A to Z: Genetics, Pathophysiology, Imaging, and Management

Hypertrophic cardiomyopathy (HCM) is a heterogeneous group of diseases related to sarcomere gene mutations exhibiting heterogeneous phenotypes with an autosomal dominant mendelian pattern of inheritance. The disorder is characterized by diverse phenotypic expressions and variable natural progression, which may range from dyspnea and/or syncope to sudden cardiac death. It is found across all racial groups and is associated with left ventricular hypertrophy in the absence of another systemic or cardiac disease. The management of HCM is based on a thorough understanding of the underlying morphology, pathophysiology, and clinical course. Imaging findings of HCM mirror the variable expressivity and penetrance heterogeneity, with the added advantage of diagnosis even in cases where a specific mutation may not yet be found. The diagnostic information obtained from imaging varies depending on the specific stage of HCM-phenotype manifestation, including the prehypertrophic, hypertrophic, and later stages of adverse remodeling into the burned-out phase of overt heart failure. However, subtle or obvious, these imaging findings become critical components in diagnosis, management, and follow-up of HCM patients. Although diagnosis of HCM traditionally relies on clinical assessment and transthoracic echocardiography, recent studies have demonstrated increased utility of multidetector computed tomography (CT) and particularly cardiac magnetic resonance (MR) imaging in diagnosis, phenotype differentiation, therapeutic planning, and prognostication. In this article, we provide an overview of the genetics, pathophysiology, and clinical manifestations of HCM, with the spectrum of imaging findings at MR imaging and CT and their contribution in diagnosis, risk stratification, and therapy.

Characteristic myocardial strain identified in hypertrophic cardiomyopathy subjects with preserved left ventricular ejection fraction using a novel multi-layer transthoracic echocardiography technique

PURPOSE

In order to evaluate compensatory mechanisms in hypertrophic-cardiomyopathy (HCM) subjects with preserved left-ventricular (LV) ejection-fraction (EF), we measured myocardial percentage endocardial strain dependency, as represented by 2D LV global longitudinal (GLS) and circumferential-strain (GCS), using a novel, multi-layer, speckle-tracking transthoracic-echocardiography (TTE) technique.

METHODS

A total of 60 subjects (40 HCM with preserved LV EF (30 male; 62 ± 15 years, all LV EF>50%)) and 20 controls (10 male; 59 ± 10 years) underwent TTE (Vivid-E9). Quantitative strain-measurements of: endocardial, all and epicardial layers were performed at each-site. We defined percentage endocardial strain dependency as the ratio of endocardial strain to epicardial strain.

RESULTS

Absolute GLS values at all views in all, endocardial and epicardial myocardial layers were significantly smaller in HCM subjects than in controls (all P<0.001). There were no significant differences between both-groups in absolute GCS values in the endocardial layers, at the mitral valve and papillary muscle levels. Percentage endocardial GCS dependency at all levels were greater in HCM subjects than in controls (all P<0.01). In HCM subjects, percentage endocardial GCS dependency at the mitral valve and papillary muscle levels revealed significant, moderate, negative correlations with LV end-diastolic and systolic dimensions (correlation coefficients -0.505, -0.451 (mitral valve level) and -0.533, -0.591 (papillary muscle level), respectively).

CONCLUSIONS

In HCM subjects with preserved LV EF, 2D LV GLS was lower than in controls, but endocardial GCS was maintained in compensation for reduction in endocardial GLS; thus percentage endocardial GCS dependency may increase, and the larger the LV size, the smaller this compensatory effect.

An Atypical Case of Apical Hypertrophic Cardiomyopathy: Absence of Giant T Waves in spite of Extreme Apical Wall Hypertrophy

Apical hypertrophic cardiomyopathy is an uncommon variant of hypertrophic cardiomyopathy, with hypertrophy mainly affecting the apex of the left ventricle. We hereby describe a case of an octogenarian female patient who was randomly diagnosed with AHCM due to other comorbidities.

The role of magnetic resonance imaging in hypertrophic cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common inheritable cardiac disorder, with an estimated prevalence of 1:500 in the general population. Most cases of HCM are phenotypically expressed in adolescence or early adulthood but age-related penetrance with certain phenotypes is increasingly recognized. Clinical manifestations of HCM are usually the result of systolic and/or diastolic dysfunction, left ventricular outflow tract (LVOT) obstruction, arrhythmias and sudden cardiac death (SCD). In recent years magnetic resonance imaging (MRI) has become established as an important tool for the evaluation of suspected HCM as it can reliably establish the diagnosis, help distinguish HCM from other causes of left ventricular hypertrophy (LVH) and identify those patients at greatest risk of SCD. This article reviews the current status of MRI in the evaluation of the HCM patient including imaging protocols, disease characterization and the emerging role of MRI for risk stratification and proband screening.