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Restrictive Cardiomyopathy

Title               

Ñ    Restrictive Cardiomyopathy

Definition

Ñ    Disorder characterised by:

·          Rigid non-compliant ventricles

That:

·          Resist diastolic filling

Ñ    May involve one or both ventricles more commonly the left

Pathogenesis

Causes

Internal Factors

Ñ    Idiopathic

Ñ    Endomyocardial fibrosis

Ñ    Loeffler’s endocarditis:

Hypereosinophilia and myocardial involvement

Systemic Factors

HS

Ñ    Amyloidosis

RS

Ñ    Sarcoidosis

E&M

Ñ    Haemochromatosis

Ñ    Glycogen storage disease

Pathological Process

Two types:

Ñ    Obliterative

Ñ    Non-obliterative

The primary disorder is endocardial thickening or myocardial infiltration with loss of myocytes, compensatory hypertrophy and fibrosis.

This results in:

Ñ    Diastolic dysfunction

Ñ    Systolic dysfunction may occur later

Ñ    Sinoatrial dysfunction

Ñ    Heart block of varying degrees

Ñ    Mural thrombosis and systemic emboli

Ñ    Atrioventricular valve malfunction:

Mitral or tricuspid regurgitation

Clinical Features

History

CVS

Ñ    Dyspnoea

Ñ    Orthopnoea

Ñ    Oedema

Examination

CVS

Ñ    Tachycardia

Ñ    Atrial and ventricular tachyarrhythmias

Ñ    Heart block

Ñ    Low volume pulse

Ñ    JVP elevated with rapid y descent

Ñ    Quiet praecordium

Ñ    S_4:

Almost all cases

Ñ    S₃ :

May occur

Ñ    Murmurs of mitral or tricuspid regurgitation

RS

Ñ    Bilateral basal crepitations (crackles)

GIT

Ñ    Hepatomegaly

Ñ    Ascites

Investigations

Imaging

Chest X-ray

Ñ    Heart size normal or small

Ñ    Enlarged in late stage

CT

Ñ    Normal pericardium

ECHO

Ñ    Normal systolic function

Ñ    Atria often dilated

Ñ    Symmetrical myocardial thickening

Ñ    Impaired ventricular filling

MRI

Ñ    Abnormal myocardial texture if myocardium is infiltrated:

Amyloid, iron

Electrophysiology

ECG

Ñ    Low voltage:

Sometimes

Ñ    Non-specific ST, T wave changes

Physiological studies

Cardiac catheterisation

Ñ    High atrial pressures with prominent y descent

Ñ    Early diastolic dip with high diastolic plateau in ventricular pressure

Ñ    Diastolic pressure is higher in the left ventricle than in the right ventricle:

Unlike constrictive pericarditis

Tissue Diagnosis

Endomyocardial Biopsy demonstrates

Ñ    Endocardial fibrosis and thickening

Ñ    Myocardial infiltration with amyloid or iron

Ñ    Chronic myocardial fibrosis

Management

Control

Drugs

Ñ    No therapy is available for most patients

Ñ    Diuretics:

Use with caution as they lower pre-load which is necessary to maintain cardiac output

Ñ    Digoxin:

Does little

Dangerous in amyloid

Ñ    Afterload reduction:

May induce profound hypotension

Ñ    Steroids:

Sarcoidosis

Hypereosinophila

Ñ    Primary amyloidosis:

Melphalan plus prednisolone with or without colchicine

Surgery

Ñ    Rarely surgical debridement may be used

Biological Agents

Phlebotomy

Ñ    Haemochromatosis

Transplantation

Ñ    Cardiac transplantation in severe cases

Ñ    Liver transplantation in familial amyloidosis

Prognosis

Ñ    Poor

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