From the Guidelines
The workup for infiltrative cardiomyopathy should start with a thorough clinical history and physical examination, followed by initial testing including electrocardiography (ECG) and echocardiography, and advanced cardiac imaging with cardiac MRI being particularly valuable, as recommended by the most recent guidelines 1.
Initial Evaluation
The initial evaluation of infiltrative cardiomyopathy involves a comprehensive approach to identify the underlying cause of the disease. This includes:
- A thorough clinical history and physical examination to identify signs and symptoms of the disease
- Electrocardiography (ECG) to assess for low voltage, conduction abnormalities, or pseudoinfarct patterns
- Echocardiography to assess ventricular wall thickness, diastolic function, and ejection fraction
Advanced Cardiac Imaging
Advanced cardiac imaging is essential in the diagnosis of infiltrative cardiomyopathy.
- Cardiac MRI is particularly valuable as it can identify specific patterns of late gadolinium enhancement characteristic of different infiltrative diseases, as noted in the guidelines 1.
- Cardiac MRI can also help to distinguish between different types of infiltrative cardiomyopathy, such as amyloidosis and sarcoidosis.
Laboratory Tests
Laboratory tests should include:
- Complete blood count
- Comprehensive metabolic panel
- Brain natriuretic peptide (BNP)
- Troponin
- Specific tests based on suspected etiology, such as serum protein electrophoresis and free light chain assay for amyloidosis, or angiotensin-converting enzyme levels for sarcoidosis
Tissue Diagnosis
Tissue diagnosis remains the gold standard for diagnosing infiltrative cardiomyopathy.
- Endomyocardial biopsy is often necessary for definitive diagnosis, though extracardiac biopsies (such as abdominal fat pad for amyloidosis) may be less invasive alternatives, as recommended by recent studies 1.
- Nuclear imaging studies like technetium pyrophosphate scanning can be particularly helpful in diagnosing transthyretin amyloidosis without requiring biopsy.
Genetic Testing
Genetic testing is recommended for suspected hereditary forms of infiltrative cardiomyopathy, such as transthyretin amyloidosis.
- Genetic testing can help to identify the underlying cause of the disease and guide treatment decisions.
- The most recent guidelines recommend a comprehensive approach to the diagnosis and management of infiltrative cardiomyopathy, including genetic testing and advanced cardiac imaging 1.
From the Research
Workup for Infiltrative Cardiomyopathy
The workup for infiltrative cardiomyopathy involves a combination of clinical evaluation, electrocardiography, echocardiography, and advanced imaging techniques.
- Clinical evaluation is essential to identify signs and symptoms of the disease, such as heart failure, atrioventricular block, and ventricular arrhythmia 2.
- Electrocardiography and echocardiography are helpful in identifying cardiac abnormalities, such as increased ventricular wall thickness, chamber dilatation, and disruption of the conduction system 2, 3.
- Advanced imaging techniques, such as cardiac magnetic resonance (CMR) and nuclear imaging, are increasingly preferred for their ability to provide detailed information about the extent of cardiac involvement and the type of substance deposited 3, 4, 5.
- CMR is particularly useful for identifying late gadolinium enhancement and T1-mapping, which can help diagnose cardiac amyloidosis and other infiltrative cardiomyopathies 3, 4.
- Nuclear imaging, such as single-photon emission computed tomography (SPECT) or positron emission tomography (PET), can provide additional diagnostic and prognostic information 5.
- Cardiac CT-scan may be useful for estimating the amyloid load, identifying potential cardiac thrombus, and ruling out associated coronaropathy 3.
Key Imaging Features
The key imaging features of infiltrative cardiomyopathies include:
- Increased ventricular wall thickness and chamber dilatation 2, 3
- Disruption of the conduction system 2
- Late gadolinium enhancement and T1-mapping on CMR 3, 4
- Abnormal uptake on nuclear imaging 5
- Estimation of amyloid load and identification of potential cardiac thrombus on cardiac CT-scan 3
Importance of Early Recognition
Early recognition of infiltrative cardiomyopathy is crucial to institute specific therapies and improve prognosis 2, 6. Noninvasive diagnosis has replaced endomyocardial biopsy for most instances in the workup of these conditions 4, 6.