Differential diagnosis of apical hypertrophic cardiomyopathy and apical displacement of the papillary muscles: a multimodality imaging point of view

Application of Cardiovascular Computed Tomography to the Assessment of Patients With Hypertrophic Cardiomyopathy

Hypertrophic cardiomyopathy is a common inherited cardiac condition in which regional myocardial thickening and scarring can lead to a range of symptoms including breathlessness, dizziness, chest pain, and collapse with loss of consciousness. It is vital to be able to understand the mechanisms behind these epiphenomena and to be able to distinguish, for example, between syncope because of arrhythmia versus syncope because of mechanical outflow tract obstruction. Therefore, we require a technique that can characterize anatomy, physiology, and myocardial substrate. Traditionally, this role has been the preserve of cardiac magnetic resonance (CMR) imaging. This review makes the case for cardiac computed tomography (CT) as an alternative imaging method. We review the use of functional CT to identify the components of outflow tract obstruction (and obstruction at other levels, which may be simultaneous), and as an aid to interventional and surgical planning. We demonstrate the added value of multiplanar isotropic reformats in this condition, particularly in cases where the diagnosis may be more challenging or where complications (such as early apical aneurysm) may be difficult to recognize with 2-dimensional techniques. In conclusion, our aim is to convince readers that cardiac CT is a highly valuable and versatile tool, which deserves wider usage and greater recognition in those caring for patients with hypertrophic cardiomyopathy.

Myocardial deformation analysis using cardiac magnetic resonance in apical hypertrophic cardiomyopathy: is it an useful tool to predict adverse outcomes?

Apical hypertrophic cardiomyopathy (AHCM) has a broad phenotypic spectrum and still poses many diagnostic and prognostic challenges. Our team performed a retrospective study to examine the prognostic value of myocardial deformation obtained with cardiac magnetic resonance tissue tracking (CMR-TT) analysis in predicting adverse events in AHCM patients. We included patients with AHCM referred to CMR in our department from August 2009 to October 2021. CMR-TT analysis was performed to characterize the myocardial deformation pattern. Clinical, other complementary diagnostic exams characteristics and follow-up data were analysed. Primary endpoint was the composite of all-cause hospitalizations and mortality. During the 12-year period, 51 AHCM patients were evaluated by CMR, with a median age of 64 years-old and male predominance. 56,9% had an echocardiogram suggestive of AHCM. The most frequent phenotype was "the relative form" (43,1%). CMR evaluation revealed a median maximum left ventricle thickness of 15 mm and the presence of late gadolinium enhancement in 78,4%. Applying CMR-TT analysis, median global longitudinal strain was - 14,4%, with a median global radial strain of 30,4% and global circumferential strain of -18,0%. During a median follow-up of 5,3 years, the primary endpoint occurred in 21,3% of patients, with a hospitalization rate of 17,8% and all-cause mortality rate of 6,4%. After multivariable analysis, longitudinal strain rate in apical segments was an independent predictor of the primary endpoint (p = 0,023), showing that CMR-TT analysis could be useful in predicting adverse events in AHCM patients.

Imaging in Heart Failure with Preserved Ejection Fraction: A Multimodality Imaging Point of View

Heart failure with preserved ejection fraction (HFpEF) is an important global health problem. Despite increased prevalence due to improved diagnostic options, limited improvement has been achieved in cardiac outcomes. HFpEF is an extremely complex syndrome and multimodality imaging is important for diagnosis, identifying its different phenotypes and determining prognosis. Evaluation of left ventricular filling pressures using echocardiographic diastolic function parameters is the first step of imaging in clinical practice. The role of echocardiography is becoming more popular and with the recent developments in deformation imaging, cardiac MRI is extremely important as it can provide tissue characterisation, identify fibrosis and optimal volume measurements of cardiac chambers. Nuclear imaging methods can also be used in the diagnosis of specific diseases, such as cardiac amyloidosis.

The Role of the Submitral Apparatus in Hypertrophic Obstructive Cardiomyopathy

Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease, is characterized by unexplained hypertrophy of any myocardial segment, and has a prevalence of 0.2% to 0.5% among the general population. As one of the phenotypes of hypertrophic cardiomyopathy, left ventricular outflow tract obstruction (LVOTO) is associated with high morbidity and mortality, including cardiac death. The integration of various factors, including septal hypertrophy, malformation of the mitral valve apparatus, and an anomalous mitral subvalvular apparatus, may contribute to the occurrence of LVOTO. Previous studies have thoroughly discussed the role of the mitral valve in the mechanisms of systolic anterior motion and LVOTO. Recent studies have shown the importance of determining the potential mechanism of the submitral apparatus in inducing systolic anterior motion and LVOTO. The authors review recent advances in knowledge regarding the submitral apparatus of patients with hypertrophic cardiomyopathy.

The Feline Cardiomyopathies: 2. Hypertrophic cardiomyopathy

Practical relevance:

Hypertrophic cardiomyopathy (HCM) is the most common form of feline cardiomyopathy observed clinically and may affect up to approximately 15% of the domestic cat population, primarily as a subclinical disease. Fortunately, severe HCM, leading to heart failure or arterial thromboembolism (ATE), only occurs in a small proportion of these cats.

Patient group:

Domestic cats of any age from 3 months upward, of either sex and of any breed, can be affected. A higher prevalence in male and domestic shorthair cats has been reported.

Diagnostics:

Subclinical feline HCM may or may not produce a heart murmur or gallop sound. Substantial left atrial enlargement can often be identified radiographically in cats with severe HCM. Biomarkers should not be relied on solely to diagnose the disease. While severe feline HCM can usually be diagnosed via echocardiography alone, feline HCM with mild to moderate left ventricular (LV) wall thickening is a diagnosis of exclusion, which means there is no definitive test for HCM in these cats and so other disorders that can cause mild to moderate LV wall thickening (eg, hyperthyroidism, systemic hypertension, acromegaly, dehydration) need to be ruled out.

Key findings:

While a genetic cause of HCM has been identified in two breeds and is suspected in another, for most cats the cause is unknown. Systolic anterior motion of the mitral valve (SAM) is the most common cause of dynamic left ventricular outflow tract obstruction (DLVOTO) and, in turn, the most common cause of a heart murmur with feline HCM. While severe DLVOTO is probably clinically significant and so should be treated, lesser degrees probably are not. Furthermore, since SAM can likely be induced in most cats with HCM, the distinction between HCM without obstruction and HCM with obstruction (HOCM) is of limited importance in cats. Diastolic dysfunction, and its consequences of abnormally increased atrial pressure leading to signs of heart failure, and sluggish atrial blood flow leading to ATE, is the primary abnormality that causes clinical signs and death in affected cats. Treatment (eg, loop diuretics) is aimed at controlling heart failure. Preventive treatment (eg, antithrombotic drugs) is aimed at reducing the risk of complications (eg, ATE).

Conclusions:

Most cats with HCM show no overt clinical signs and live a normal or near-normal life despite this disease. However, a substantial minority of cats develop overt clinical signs referable to heart failure or ATE that require treatment. For most cats with clinical signs caused by HCM, the long-term prognosis is poor to grave despite therapy.

Areas of uncertainty:

Genetic mutations (variants) that cause HCM have been identified in a few breeds, but, despite valiant efforts, the cause of HCM in the vast majority of cats remains unknown. No treatment currently exists that reverses or even slows the cardiomyopathic process in HCM, again despite valiant efforts. The search goes on.

A Novel Case of Yamaguchi Syndrome in a Hispanic Male

Yamaguchi syndrome or apical hypertrophic cardiomyopathy (HCM) is a unique variant of HCM. It is characterized by localized hypertrophy involving the left ventricular apex rather than the left ventricular septum. This syndrome has been traditionally seen in the Asian population, particularly those of Japanese descent. We present an interesting case of Yamaguchi syndrome seen in a Hispanic male.

A 48-year-old Hispanic male presented with epigastric tenderness and was admitted to the hospital for a non-ST-segment elevation myocardial infarction. His diagnostic catheterization revealed no significant coronary artery disease. However, his echocardiogram revealed apical hypertrophy and narrowing of the left ventricular cavity at the apex, consistent with Yamaguchi syndrome. Case reports such as ours serve to help clinicians broaden their differential diagnoses when approaching patients with acute coronary syndrome-like symptoms to include diagnoses such as Yamaguchi syndrome.