Cardiomyopathy I – Overview & Genetics

Learning Objectives

• Understanding the macro and micro difference of main cardiomyopathies

• Characterise Hypertrophic cardiomyopathies (HCM) from a: Morphological,Molecular Genetic basis, Pathogenesis

What is cardiomyopathy?

Cardiomyopathy - is a heterogeneous group of disease at affect the myocardium in the heart which can latter cause heart releated issues such as: arrythmias, heart failure and Sudden Cardiac Death (SCD)

• Structure problems with cardiomyopathy

  • Heart muscle becomes enlarged or abnormally thick or rigid

• Function problems with cardiomyopathy

  • Loses the basic ability to pump blood effectively to the body

Cardiomyopathy classifications

Primary Cardiomyopathy

- Relates to genetics causing the disease either acquired or mixed

• TYPES of Primary Cardiomyopathies

  • Dilated Cardiomyopathy (DCM)

  • Restrictive Cardiomyopathy (RCM)

  • Arrhythmogenic right ventricular cardiomyopathy (ARCV)

  • Hypertrophic cardiomyopathy (HCM)

• Dilated Cardiomyopathy (DCM)

  • Heart muscle is abornamlly thin

  • LV (Left ventricle) dilation

  • Systolic (heart contraction) function is impaired which means heart contraction is weakened

• Causes of DCM are commonly familial via autosomal dominant inheritance

• Clinical features:

  • Decreased exercise capacity,

  • Fatigue,

  • Dyspnea,

  • Paroxysmal nocturnal dyspnea,

  • Abnormal bloating

• Restrictive Cardiomyopathy (RCM)

  • Heart muscle becomes rigid and unable to relax and fill with blood

  • Reduced diastole (heart relaxation)

  • No alteration or systolic function

• Causes: familial form or sometimes associated to health problems

• Clinical Features

  • Fatigue

  • Exercise intolerance

  • Dyspnea

  • Syncope

  • Palpitation

• Arrhythmogenic right ventricular cardiomyopathy (ARCV)

  • The presence of progressive replacement of myocardium with adipose and fibrous tissue (fats in the heart muscle tissue)

  • Interrupts normal electrical signalling in the heart leading to poor contractions causing irregular and potentially life-threatening heart

• Causes: most cases are a familial transmissions hence autosomal dominant inherited

• Hypertrophic cardiomyopathy (HCM)

  • The heart muscle becomes abnormally thickened ( over 15mm in adults)

  • A common inherited genectic heart condition which is again via autosomal dominant inheritance

  • HCM can develop at any age which is common in people in their 30s

• There are 2 types of HCM:

  • Obstructive (HOCM)

  • Non-Obstructive HCM

HCM - Left Ventricular Outflow Tract (LVOT)

• When muslcle walls of the ventricles in particular the left ventricle becomes thick will casue narrowing of the mitral valve

• Mitral valve when it narrows less blood is able to pass through in comparison to a healthy heart from ventricle to aorta

• As the aorta is the valve which pumps oxygenated blood to the body. Less oxygen will reach to cells that requires it

• Symptoms:

  • Arryhtmia

  • Chest pain

  • Fatigue

  • Pounding feeling in the chest

  • Shortness of breath

Complications can arise from LVOT including heart failure and Sudden Cardiac Death (SCD) which is sudden loss of heart function due to dangerously fast heartbeat (ventricular tachycardia)

An example of these is Eriksens collapse in the Euros relating to sport players just collapsing on field due to heavy sport activity

Secondary Cardiomyopathy

- Cardiomyopathy that is acquired instead of genetic which can develop due to another health condition