Multimodality imaging for the diagnosis of infiltrative cardiomyopathies

Infiltrative cardiomyopathies result from the deposition or anomalous storage of specific substances in the heart, leading to impaired cardiac function and heart failure. In this review, we describe the utility of a variety of imaging modalities for the diagnosis of infiltrative cardiomyopathies and provide algorithms for clinicians to use to evaluate patients with these disorders. We have divided infiltrative cardiomyopathies into two different categories: (1) infiltrative cardiomyopathies characterised by increased wall thickness (eg, cardiac amyloidosis and Anderson-Fabry disease (AFD)) and (2) infiltrative cardiomyopathies that can mimic ischaemic or dilated cardiomyopathies (eg, cardiac sarcoidosis (CS) and iron overload cardiomyopathy). Echocardiography is the first modality of choice for the evaluation of cardiomyopathies in either category, and the differential can be narrowed using cardiac magnetic resonance (CMR) and nuclear imaging techniques. The diagnosis of cardiac amyloidosis is supported with key findings seen on echocardiography, CMR and nuclear imaging, whereas AFD can be suggested by unique features on CMR. CMR and nuclear imaging are also important modalities for the diagnosis of CS, while iron overload cardiomyopathy is mostly diagnosed using tissue characterisation on CMR. Overall, multimodality imaging is necessary for the accurate non-invasive diagnosis of infiltrative cardiomyopathies, which is important to ensure appropriate treatment and prognostication.

Infiltrative cardiomyopathy

Infiltrative cardiomyopathies are comprised of a variety of inherited or acquired conditions. Myocardial involvement is often part of a complex systemic disorder, but sometimes the disease can manifest predominantly in the heart. Clinical manifestations are heterogeneous, from mild symptoms to early cardiac death. A multimodality imaging approach by means of echocardiography, cardiovascular magnetic resonance (CMR), and molecular imaging is necessary; a comprehensive assessment of morphologic, functional, tissue, and metabolic changes is the key to improve the pathophysiologic understanding of these diseases, favouring early differential diagnosis and risk stratification of patients. Furthermore, quantitative, non-invasive assessment of tissue pathology is now available and plays a crucial role in the follow-up of patients affected by infiltrative cardiomyopathies, improving their management and potentially guiding the development of existing and new therapies.

The Importance of Multimodality Imaging in the Diagnosis and Management of Patients with Infiltrative Cardiomyopathies: An Update

Infiltrative cardiomyopathies (ICMs) comprise a broad spectrum of inherited and acquired conditions (mainly amyloidosis, sarcoidosis, and hemochromatosis), where the progressive buildup of abnormal substances within the myocardium results in left ventricular hypertrophy and manifests as restrictive physiology. Noninvasive multimodality imaging has gradually eliminated endomyocardial biopsy from the diagnostic workup of infiltrative cardiac deposition diseases. However, even with modern imaging techniques’ widespread availability, these pathologies persist in being largely under- or misdiagnosed. Considering the advent of novel, revolutionary pharmacotherapies for cardiac amyloidosis, the archetypal example of ICM, a standardized diagnostic approach is warranted. Therefore, this review aims to emphasize the importance of contemporary cardiac imaging in identifying specific ICM and improving outcomes via the prompt initiation of a targeted treatment.

Positron emission tomography imaging in cardiovascular disease

Positron emission tomography (PET) imaging is useful in cardiovascular disease across several areas, from assessment of myocardial perfusion and viability, to highlighting atherosclerotic plaque activity and measuring the extent of cardiac innervation in heart failure. Other important roles of PET have emerged in prosthetic valve endocarditis, implanted device infection, infiltrative cardiomyopathies, aortic stenosis and cardio-oncology. Advances in scanner technology, including hybrid PET/MRI and total body PET imaging, as well as the development of novel PET tracers and cardiac-specific postprocessing techniques using artificial intelligence will undoubtedly continue to progress the field.

Heart involvement in AL-amyloidosis. Current state of the issue

AL cardiac amyloidosis is a relatively rare disorder that belongs to the group of infiltrative cardiomyopathies. Diagnosis of primary amyloidosis is challenging due to many unspecific symptoms and sings, which often leads to late diagnosis when treatment options are limited. Primary amyloidosis particularly needs to be excluded in patients with heart failure with preserved ejection fraction. Therapy in cardiac amyloidosis has to main vectors: 1) chemotherapy to eliminate amyloidogenic plasmatic cells 2) heart failure treatment. The main challenge for cardiologists is to support hemodynamics until response to chemotherapy occurs. In the article the issue of diagnostics, risk stratification and treatment of primary cardiac amyloidosis is addressed.