Restrictive Cardiomyopathy

What is it?

Restrictive cardiomyopathy is the least common type of cardiomyopathy and accounts for a very small population of patients. It is characterized by a rigid myocardial wall that decreases the expansion of the chamber wall during ventricular filling.

As the ventricles fail to accept full blood flow from the atria, atrial pressure increases leading to pulmonary congestion, and eventually to right sided HF. Symptoms worsen during activity as the increased HR decreases ventricular filling time even more.

Causes

Restrictive cardiomyopathy can be idiopathic, resulting from generalized infiltrative processes such as amyloidosis or sarcoidosis, or be due to scarring from therapeutic radiation.

  • Amyloidosis & Sarcoidosis
    • Usually affects both ventricals, with the size remaining relatively normal or possibly slightly decreased. Deposits impact the conduction pathway of the heart and can lead to dysrhythmias
  • Therapeutic Radiation
    • Scarring from radiation
  • Idiopathic
    • No evident cause
Diagnostics
  • ECG
    • Will show low-voltage QRS complexes, and cardiac conduction abnormalities.
  • ECHO
    • The severity of the diastolic dysfunction will be evident, in the rate and volume of ventricular filling.
    • A decreased EF is seen in later stages of the disease.
  • Biopsy
    • Endomyocardial biopsy obtains a sample from the right ventricular wall in an attempt to determine the disorder causing the symptoms.
Signs & Symptoms
  • Cardiac
    • S4 (heart at 5th intercostal space, left midclavicular line)
    • Systolic murmur or both mitral and tricuspid regurgitation
    • Decreased peripheral pulses
Treatment
  • Cardiac Output
    • Diuretics in small doses if fluid overloaded
    • Beta blockers (diastolic relaxation, improves filling)
    • Calicum┬áchannel blockers (diastolic relaxation, improves filling)
  • Dysrhythmias
    • Atrial fibrillation is the most common (convert to SR)
    • Consider permanent pacemaker for bradycardia or heart block
  • Anticoagulation
    • Warfarin (Coumadin)
    • ASA
    • Rivaroxaban (Xeralto)
    • Dabigatran (Pradaxa)
  • Amyloidosis
    • Chemotherapy
    • Melphalan (Alkeran) has the highest success rate.
  • Sarcoidosis
    • May be treated with high dose steroids and possibly immunosuppression therapy
  • AVOID
    • ACE-I (will cause severe hypotension)
Alternative Treatments
  • Valve Replacement or Repair
    • May help control symptoms
  • Mechanical Circulatory Assist
    • Ventricular Assist Devices (VADs) may be suitable in selected patients
  • Cardiac Transplant