What is the recommended workup for a patient with suspected restrictive heart disease?

Recommended Workup for Suspected Restrictive Heart Disease

The comprehensive workup for suspected restrictive cardiomyopathy should include echocardiography with Doppler, cardiac MRI, electrocardiography, laboratory testing, and in select cases, endomyocardial biopsy to establish the diagnosis and identify the underlying etiology.

Initial Diagnostic Evaluation

History and Physical Assessment

• Assess for signs and symptoms of biventricular heart failure
• Evaluate for orthostatic blood pressure changes
• Check for jugular venous pressure elevation
• Listen for heart murmurs and rales
• Assess for displaced apex beat
• Document pulse rate and regularity

First-Line Testing

• Two-dimensional echocardiography with Doppler is the cornerstone initial test 1

  • Assess for:
    • Normal or reduced diastolic volumes
    • Normal or reduced systolic volumes
    • Normal ventricular wall thickness
    • Restrictive filling pattern
    • Atrial enlargement
    • Valvular function

• 12-lead ECG should be performed in all patients 1

  • Look for:
    • Low voltage (suggestive of amyloidosis)
    • Conduction abnormalities
    • Arrhythmias

• Laboratory testing 1

  • Complete blood count
  • Serum electrolytes (including calcium and magnesium)
  • Blood urea nitrogen and creatinine
  • Liver function tests
  • Thyroid-stimulating hormone
  • Fasting blood glucose/glycohemoglobin
  • Lipid profile
  • NT-proBNP/BNP (helpful for risk stratification)
  • Cardiac troponins (particularly for suspected amyloidosis)

• Chest radiograph (posterior-anterior and lateral) 1

Advanced Diagnostic Testing

• Cardiac MRI with late gadolinium enhancement 1

  • Indicated when:
    • Echocardiography is inconclusive
    • Suspicion of infiltrative or storage disease
    • Need to differentiate from other cardiomyopathies
    • Assessment of myocardial fibrosis pattern

• 24-48 hour ambulatory electrocardiographic monitoring 1

  • To identify arrhythmias and assess risk of sudden cardiac death
  • Consider extended monitoring if palpitations or lightheadedness present

• Specific disease screening based on clinical suspicion 1

  • Hemochromatosis screening
  • Amyloidosis evaluation (serum free light chains, immunofixation)
  • Sarcoidosis assessment
  • Screening for storage diseases

Specialized Testing for Differential Diagnosis

• Cardiac catheterization with hemodynamic assessment 1

  • Consider when:
    • Noninvasive testing is inconclusive
    • Need to differentiate from constrictive pericarditis
    • Evaluate for "square root sign" in pressure tracings

• Coronary angiography 1

  • Indicated in patients with:
    • Angina or evidence of myocardial ischemia
    • Risk factors for coronary artery disease

• Endomyocardial biopsy 1

  • Consider when:
    • Specific diagnosis is suspected that would influence therapy
    • Differentiation between various infiltrative cardiomyopathies is needed
    • Not recommended for routine evaluation 1

• Genetic testing 2

  • Particularly useful for:
    • Familial forms of restrictive cardiomyopathy
    • Suspected transthyretin amyloidosis
    • Storage diseases

Diagnostic Algorithm

1. Start with echocardiography, ECG, chest X-ray, and basic laboratory tests
2. If diagnosis remains uncertain, proceed to cardiac MRI
3. If infiltrative disease is suspected, order disease-specific tests:
   • For amyloidosis: serum/urine protein electrophoresis, free light chains
   • For hemochromatosis: iron studies, ferritin
   • For sarcoidosis: chest CT, PET scan
4. Consider cardiac catheterization to confirm restrictive physiology and rule out constrictive pericarditis
5. Perform endomyocardial biopsy if specific diagnosis would change management

Common Pitfalls and Caveats

• Restrictive cardiomyopathy can be misdiagnosed as:

  • Constrictive pericarditis (differentiate with cardiac MRI and catheterization)
  • Hypertrophic cardiomyopathy (particularly infiltrative forms)
  • Heart failure with preserved ejection fraction

• Cardiac amyloidosis is frequently underdiagnosed in elderly patients with heart failure with preserved ejection fraction 3

• Endomyocardial biopsy should not be performed routinely but reserved for cases where a specific diagnosis would influence therapy 1

• The diagnosis of idiopathic restrictive cardiomyopathy should only be made after excluding all specific etiologies 4