Definition

A myocardial disorder in which the heart muscle is structurally and functionally abnormal in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to explain the observed myocardial abnormality 

--- European Society of Cardiology

 

Main types

  1. Hypertrophic cardiomyopathy
  2. Dilated cardiomyopathy
  3. Restrictive cardiomyopathy
  4. Arrhythmogenic right ventricular cardiomyopathy
  5. Obliterative cardiomyopathy

 

1. Hypertrophic cardiomyopathy

Definition

  • a group of inherited conditions that produce hypertrophy of the myocardium, which is not secondary to any other causes e.g. aortic stenosis, hypertension

Aetiology

  • Approximately 50% of cases are familial autosomal dominant
  • With mutations in the genes encoding for sarcomeric proteins
  • these sarcomeric proteins include: most commonly beta-myosin heavy chain, myosin-binding protein C, and Troponin T.

 

Epidemiology

  •  Prevalence: 1 in 500

 

Features

  • characterized by variable myocardial hypertrophy, according to the underlying genetic mutation
  • frequently involving the interventricular septum and disorganization of cardiac myocytes and myofibrils
  • beta-myosin heavy chain: marked hypertrophy
  • Troponin T: mild hypertrophy but associated with a high risk of sudden death
  • 25% patients have dynamic left ventricular outflow tract obstruction due to combined effect of hypertrophy + systolic anterior motion of the anterior mitral valve leaflet + rapid ventricular ejection

 

Symptoms and signs



Investigations



Management

  1. Implantable cardioverter-defibrillator (ICD) (for Pt with increased risk of sudden death)
  2. Beta blocker and/or verapamil (for chest pain and dyspnoea)
  3. Disopyramide (for left ventricular outflow tract obstruction)
  4. Alcohol (non-surgical) ablation of the septum (to reduce outflow tract obstruction and to improve exercise capacity)
  5. Surgical resection of septal myocardium 
  6. Cardiac transplantation for end-stage heart failure
  7. Screen family members with ECG or echocardiography

 

Complications

  1. Heart failure
  2. Arrhythmias (atrial and ventricular)
  3. Infective endocarditis

 

2. Dilated cardiomyopathy

Defintion

  • it is a myocardial disorder characterized by dilatation of the ventricular chambers and systolic dysfunction with preserved wall thickness

Aetiology

  • two types: Familial and sporadic

 



Epidemiology

  •  prevalence: 1 in 2500

 

Symptoms and signs



Investigations



Management

  1. Treat heart failure
  2. Treat arrhythmias
  3. ICD for recurrent ventricular tachycardias
  4. Cardiac transplantation for end-stage heart failure

 

Complications

  1. Sudden death
  2. Embolism
  3. Heart failure
  4. arrhythmias (atrial and ventricular)

 

3. Restrictive cardiomyopathy

Definition

  • a rare condition in which there is normal or decreased volume of both ventricles with bi-atrial enlargement, normal wall thickness, normal cardiac valves and impaired ventricular filling with restrictive physiology but near normal systolic function

 

Aetiology

  • commonest is amyloidosis
  • sarcoidosis
  • Loeffler’s endocarditis (a form of hypereosinophilic syndrome)
  • endomyocardial fibrosis (a form of hypereosinophilic syndrome)
  • can be familial

 

Epidemiology

  • rare

 

Symptoms and signs



Investigations



Management

  1. No specific treatment
  2. Manage the underlying cause
  3. Cardiac transplantation in end-stage heart failure

 

Complications

  1. Heart failure
  2. Embolism

 

4. Arrhythmogenic right ventricular cardiomyopathy

Definition

  • an inherited condition that predominantly affects the right ventricle with fatty or fibro-fatty replacement of myocytes, leading to segmental or global dilatation.
  • these fibro-fatty replacements lead to ventricular arrhythmias 
  • risk of sudden death in its early stages
  • risk of right ventricular or biventricular failure in its later stages

 

Aetiology

  • genetic: autosomal dominant (mainly) and recessive
  • for autosomal dominant, there are mutations in four genes: cardiac ryanodine receptor RyR2, desmoplakin, plakophillin-2, and transforming growth factor-beta gene
  • there are two recessive forms: Naxos disease (characterized by wooly hair and palmoplantar keratoderma) and Carvajal syndrome

 

Epidemiology

  • prevalence: 1 in 5000

 

Symptoms and signs

  • mostly asymptomatic
  • symptomatic ventricular arrhythmias
  • syncope
  • family history of sudden death
  • signs and symptoms of right heart failure

 

Investigations



Management

  1. Beta-blocker for non-life-threatening arrhythmias
  2. Amiodarone or sotalol for symptomatic arrhythmias
  3. ICD for refractory or life-threatening arrhythmias
  4. Cardiac transplantation for intractable arrhythmia or cardiac failure

 

5. Obliterative cardiomyopathy

 

Definition

  • a cardiomyopathy that involves the endocardium of one or both ventricles
  • Characterized by thrombus formation on the endocardium of the apex and inflow segments of one or both ventricles
  • elaborate fibrosis with gradual obliteration of the ventricular cavities
  • mitral and tricuspid valves become regurgitant
  • ultimately, causing endomyocardial fibrosis

 

Aetiology

  • any cause of systemic hypereosinophilia e.g eosinophilic leukaemia, Churg-Strauss syndrome, Bechet’s syndrome, and idiopathic hypereosinophilia

 

Epidemiology

  • in tropical countries, it can lead to 10% of cardiac deaths
  • mortality is high (50% at 2 years)

 

Symptoms and signs

  • Symptoms and signs of heart failure
  • Symptoms and signs of pulmonary and systemic embolism

 

Management

  1. Anticoagulation and antiplatelet therapy
  2. Diuretics for heart failure symptoms
  3. Surgery (tricuspid and/or mitral valve replacement with decortication of the endocardium)

     

    References

    1. Classification of the cardiomyopathies: a position statement from the European Society Of Cardiology Working Group on Myocardial and Pericardial Diseases. Elliott P, Andersson B, Arbustini E, et al. Eur Heart J. 2008;29(2):270.
    2. Kumar and Clark’s Clinical Medicine
    3. Oxford Handbook of Clinical Medicine
    4. Rapid Medicine

     

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