Makindo Medical Notes

Related Subjects: |Dilated Cardiomyopathy |Hypertrophic cardiomyopathy (HCM - HOCM) |Peripartum cardiomyopathy |Restrictive Cardiomyopathy |Takotsubo Cardiomyopathy

Consider infiltrative diseases. There is a significant risk of embolism, arrhythmias, and sudden death.

About

• Restrictive cardiomyopathy is characterized by restricted ventricular filling, leading to "diastolic failure."

Aetiology

• Myocardial thickening, fibrosis, or infiltration (e.g., amyloid deposition).
• Restricted diastolic filling due to stiff or rigid ventricular walls.

Causes

• Idiopathic causes or connective tissue diseases.
• Radiotherapy-induced myocardial changes.
• Infiltrative diseases:
  • Cardiac amyloidosis: Associated with abnormal protein deposition in the heart.
  • Haemochromatosis: Iron overload leading to cardiac damage.
  • Sarcoidosis: Inflammatory infiltrates causing conduction disturbances.
  • Eosinophilic endomyocardial disease: Often part of a hyper-eosinophilic syndrome.
  • Fabry's disease: A metabolic disorder, where galactose infusion can improve cardiac function.
• Other causes:
  • Carcinoid syndrome.
  • Antracycline (chemotherapy-induced cardiotoxicity).
  • Scleroderma (systemic sclerosis).

Clinical Features

• Atrial fibrillation (AF), dependent oedema, dyspnoea, and reduced exercise tolerance.
• Raised jugular venous pressure (JVP), which may rise during inspiration (Kussmaul's sign).
• JVP demonstrates steep x and y descents.
• Other signs include the presence of an S3 heart sound, ascites, ankle oedema, and hepatomegaly.

Differential Diagnosis

• Key differentiation is from constrictive pericarditis, which is treatable with surgery.

Investigations

• Blood tests: FBC, U&E, LFTs, ESR.
• ECG: Low voltage QRS, ST/T wave changes.
• Echocardiography: Shows non-dilated ventricles, atrial enlargement, preserved left ventricular function, diastolic dysfunction. A "granular sparkly" appearance of the myocardium is suggestive of amyloidosis.
• CT / MRI: Useful to exclude constrictive pericarditis.
• Serum amyloid protein scan: To assess for systemic amyloidosis.
• Endomyocardial biopsy: May be considered to confirm diagnosis, especially in infiltrative diseases.

Management

• Treat heart failure symptoms with diuretics and vasodilators.
• Consider anticoagulation to reduce the risk of thromboembolic events.
• Cytotoxic therapy for eosinophilic heart disease.
• Prognosis is generally poor, with limited treatment options available.