16. Cardiomyopathy Flashcards
Main types of cardiomyopathy
- Dilated - ventricular enlargement without muscular thickening (causing less contractility).
- Hypertrophic - massive left ventricular hypertrophy, usually most prominent in the inter-ventricular septum.
- Restrictive
- Arrhythmogenic right ventricular
Types of dilated cardiomyopathy
- Familial DCM
- with family history
- autosomal dominant inheritance and associated with lots of different gene mutations. - Sporadic DCM
- no family history
- happens in a person with a normal heart in response to an insult
What is “cardiomyopathy”?
A myocardial disorder in which the heart muscle is structurally and functionally abnormal without coronary artery disease, hypertension, valvular or congenital diseases.
Clinical features of dilated cardiac myopathy.
Acute presentations:
- arrhythmias
- sudden cardiac death
- thromboembolism and stroke
Chronic presentations:
- most likely to present as heart failure
- may be symptomless
- may have a history of a preceding illness if sporadic
**Important to ascertain if there is family history of sudden unexpected deaths!
Examination of dilated cardiac myopathy
Signs of heart failure - oedema, raised JVP, loud third and/or fourth heart sound
CXR: signs of heart failure
ECG: may show arrhythmias, conduction abnormalities or non specific ST segment changes
Echocardiogram: gives an idea to the pumping of the heart and if there are any valve problems or structural problems
Can also perform cardiac MRI, coronary angiography, cardiac biopsy (rarely done).
Treatment of dilated cardiac myopathy.
- Diuretics
- ACE inhibitors and beta blockers
- Anticoagulation
- Pacemakers or implantable defibrillators
The commonest indication for heart transplantation.
Prognosis of dilated cardiac myopathy
- Not curable.
- Treatments only manage symptoms and prevent complications.
- (As the disease progresses, the heart failure worsens.) Risk of sudden cardiac death.
What is hypertrophic obstructive cardiomyopathy?
Hypertrophic cardiomyopathy when the large, bulky septum gets in the way of the left ventricular outflow tract during systole. Known as dynamic left ventricular outflow tract obstruction.
Epidemiology of hypertrophic cardiomyopathy
- Most cases are familial.
- Most common cause of sudden cardiac death in young people.
- Tends to affect men and those of African-American origin.
What is systolic anterior motion of the mitral valve or ‘SAM’?
Hypertrophy cardiomyopathy where the anterior leaflet of the mitral valve moves anteriorly, towards the left ventricular outflow tract during systole due to the large drag force of the hypertrophied septum.
Causes of hypertrophic cardiomyopathy
- Most cases are familial.
- Most common genetic cardiovascular disease.
- Most common mutations affect the beta myosin heavy chain and myosin binding protein C, causing hypertrophy and a disorganised structure to the cardiac myocytes.
Risk factors for sudden death in hypertrophic myocardiopathy
Sudden death is usually due to arrhythmias or obstruction of the LV outflow tract.
- flat or hypotension response on exercise
- family history of sudden cardiac death (<50 yo)
- non-sustained ventricular tachycardia
- prior unexplained syncope
Examination of hypertrophic cardiomyopathy
- Ejection systolic murmur
- Jerky carotid pulse
- Fourth heart sound
- Double apical pulse
- if SAM, pan-systolic murmur
ECG: ST and T wave changes
Echocardiography
Cardiac MRI
Genetic analysis
Symptoms of hypertrophic cardiomyopathy
- Most patients are asymptomatic.
- Patients may present with chest pain, dyspnoea and syncope (especially during exercise)
Treatment for hypertrophic cardiomyopathy
- Alleviating symptoms and preventing sudden death
- Patients with 2 or more risk factors should be considered for an implantable cardioverter-defibrillator (ICD).
May need a heart transplant.
