Restrictive Cardiomyopathy (RCM)

Rare cardiomyopathy characterized by marked diastolic dysfunction, normal (or near-normal) systolic function, and normal ventricular volumes.

---

🔹 Epidemiology

• Least common form of cardiomyopathy (2–5%).

• >80% develop heart failure.

• Prognosis: generally poor, 5-year survival ≈ 50% (adults), high sudden cardiac death risk in pediatrics.

---

🔹 Etiology (Mnemonic: “PLEASe Help”)

Postradiation/postsurgery fibrosis
Löffler endocarditis (hypereosinophilia)
Endocardial fibroelastosis
Amyloidosis (MC in high-income countries)
Sarcoidosis
Hemochromatosis

Categories:

1. Infiltrative – amyloidosis, sarcoidosis, hyperoxaluria

2. Storage disorders – hemochromatosis, transfusion iron overload, lysosomal diseases (Fabry, Gaucher, MPS, glycogen storage)

3. Endomyocardial – fibrosis (Africa), Löffler, fibroelastosis, carcinoid, metastasis

4. Iatrogenic/Non-infiltrative – radiation, anthracycline chemo, postsurgical, systemic sclerosis, idiopathic/familial

---

🔹 Pathophysiology

Infiltration or fibrosis → ↓ ventricular compliance → impaired diastolic filling → ↑ filling pressures → biatrial enlargement, pulmonary/systemic venous congestion → late decline in systolic function → hypotension + CHF.

---

🔹 Clinical Features

Symptoms:

• Dyspnea on exertion (MC)

• Fatigue, edema, palpitations, syncope, SCD

Exam findings:

• Right HF signs: JVD, hepatomegaly, ascites, edema, positive Kussmaul sign

• Auscultation: S4 gallop, MR/TR murmurs, AF common

• Systemic clues:

  • Amyloidosis → macroglossia, carpal tunnel

  • Hemochromatosis → bronze skin

  • Sarcoidosis → erythema nodosum

---

🔹 Diagnosis

Initial tests:

• ECG: Low voltage QRS (in amyloidosis), AV block, AF

  
  
  

• CXR: Biatrial enlargement, pulmonary congestion

  
  
  

• Labs: CBC (eosinophilia), renal/hepatic function, NT-proBNP, troponin

Echocardiography (first-line):

• Severe diastolic dysfunction

• Normal/reduced volumes

• Preserved EF (early)

• Biatrial enlargement

• Possible increased wall thickness (amyloidosis, sarcoidosis, storage disease)

  
  
  

Advanced studies:

• Cardiac MRI: infiltration/fibrosis patterns

• Endomyocardial biopsy: gold standard for etiology (amyloid, iron, granulomas, eosinophils)

• Catheterization: LVEDP > RVEDP; helps distinguish from constrictive pericarditis

---

🔹 Differential: RCM vs Constrictive Pericarditis

Feature	RCM	Constrictive Pericarditis
Pericardium	Normal	Thickened, calcified
Echo	↓ resp. variation	Septal shift w/ respiration
Cath	LVEDP > RVEDP, RVSP ≥ 55	LVEDP ≈ RVEDP, normal RVSP
Auscultation	S4 gallop	Pericardial knock
X-ray	Biatrial enlargement	Pericardial calcification

---

🔹 Treatment

General approach:

1. Treat CHF symptoms

2. Manage arrhythmias/thromboembolism risk

3. Disease-specific therapy

4. Consider transplant if refractory

Symptom management:

• Diuretics: gentle diuresis for congestion (avoid over-diuresis → hypotension)

• β-blockers / CCBs: slow HR, ↑ filling time (start cautiously)

• ACEI/ARB: afterload reduction, but risk of hypotension

• Avoid digoxin (worsens amyloidosis/sarcoidosis)

Arrhythmia management:

• Early cardioversion for AF

• Amiodarone or sotalol preferred

• Pacemaker (AV block) / AICD (SCD prevention)

Anticoagulation:

• Indicated in AF, thrombus, or high risk

Disease-specific therapy:

• Amyloidosis: chemo, stem cell transplant, tafamidis, patisiran, liver transplant (ATTR)

• Sarcoidosis: immunosuppression, pacemaker/AICD

• Hemochromatosis: phlebotomy, chelation

• Hypereosinophilia: steroids, IFN-α, hydroxyurea

• Radiation/chemo: supportive ± transplant

Advanced/severe disease:

• LVAD (bridge/destination therapy)

• Heart transplant (± liver in amyloidosis)

• Palliative care if not a candidate