Cardiomyopathy Flashcards
What is meant by cardiomyopathy
A group of diseases of the myocardium that affect the mechanical or electrical function of the heart
4 types of cardiomyopathy
- Hypertrophic
- Dilated
- Restricted
- Arrythmogenic right ventricular
Are cardiomyopathy disorders generally inherited or acquired?
Inherited (tho some are acquired)
Risk factors of cardiomyopathy
Family history of cardiomyopathy High BP Obesity Diabetes Previous MI
What is hypertrophic cardiomyopathy (HCM)
Ventricular hypertrophy/thickening of the muscle
particularly the intraventricular septum
Hypertrophic cardiomyopathy (HCM): epidemiology
Quite common, second most common cardiomyopathy (behind dilated)
• 1/500 people have it
• Autosomal dominant - familial
• May present at any age
• Most common cause of sudden cardiac death in the young
• HCM refers to otherwise unexplained primary cardiac hypertrophy
What is most common cardiomyopathy
Dilated
What is most common cause of sudden cardiac death in young people
Hypertrophic Cardiomyopathy (HCM)
Hypertrophic cardiomyopathy (HCM): Pathophysiology
- Caused by sarcomeric protein gene mutations e.g troponin T and B- myosin
- The hypertrophic, non-compliant ventricles impair diastolic filling resulting in reduced stroke volume and thus cardiac output
- Conduction is also affected in the heart by the disarray of cardiac myocytes
(- All in the absence of hypertension and valvular disease)
Clinical presentation of Hypertrophic Cardiomyopathy
- Sudden death may be the first manifestation
- Chest pain, Angina, dysponea, dizziness, palpitations, syncope
- Left ventricular outflow obstruction may be a feature
- Cardiac arrhythmia
- Ejection systolic murmur
- Jerky carotid pulse
Diagnosis of Hypertrophic Cardiomyopathy
• ECG: is abnormal and shows signs of left ventricular hypertrophy with progressive T wave inversion and deep Q waves
- Echocardiogram: shows ventricular hypertrophy and a small left ventricle cavity
- Genetic analysis can confirm diagnosis since most cases are autosomal dominant and familial
Treatment of Hypertrophic Cardiomyopathy
- Amiodarone - anti-arrythmatic medication, if at high risk of arrhythmia then can place an implantable cardiac defibrillator
- Calcium channel blocker e.g. Verampil
- Beta-blocker e.g. Atenolol
Describe dilated cardiomyopathy
Dilated left ventricle which contracts poorly/has thin muscle
Dilated Cardiomyopathy: Epidemiology
Most common cardiomyopathy
Autosomal dominant - familial
Aetiology of Dilated Cardiomyopathy
Ischaemia
Alcohol
Thyroid disorder
Familial/genetic
Pathophysiology of Dilated Cardiomyopathy
- *Caused by Cytoskeletal Gene Mutations
- Left ventricle or right ventricle or all 4 chamber dilatation and thus dysfunction
- Theory is that poorly generated contractile force leads to progressive dilatation of heart with some diffuse interstitial fibrosis
Clinical presentation of Dilated Cardiomyopathy
- Shortness of breath at first and fatigue
- Dysponea
- Heart failure since can’t contract
- Arrhythmias
- Thromboembolism
- Sudden death
- Increased jugular venous pressure
Diagnosis of Dilated Cardiomyopathy
- CXR: cardiac enlargement
- ECG: tachycardia, arrhythmia and non-specific T wave changes
- Echo: shows dilated ventricles
Treatment of Dilated Cardiomyopathy
Treat as you would Heart Failure and Atrial Fibrillation
Aetiology of Restricted Cardiomyopathy
Amyloidosis
Idiopathic
Sarcoidosis
End-myocardial fibrosis
Pathophysiology of Restricted Cardiomyopathy
Normal or decreased volume of both ventricles with bi-atrial enlargement, normal wall thickness, normal cardiac valves and impaired ventricular filing.
Poor dilation of the heart restricts its the ability of the heart to take on
blood and pass it to the rest of the body
Rigid myocardium restricts diastolic ventricular filling
Clinical presentation of Restricted Cardiomyopathy
Similar to constructive pericarditis Dysponea, fatigue and embolic symptoms
Elevated jugular venous pressure with diastolic collapse and elevation of venous pressure with inspiration
Hepatic enlargement, ascites and dependent oedema
Third and fourth heart sounds
Diagnosis of Restricted Cardiomyopathy
CXR, ECHO & ECG are abnormal but non-specific
*Cardiac catheterisation helps to diagnose restrictive cardiomyopathy
Treatment of Restricted Cardiomyopathy
No specific treatment with poor prognosis
Patients die within a year
Can consider cardiac transplantation
What is Arrhythmogenic Right Ventricular Cardiomyopathy
Progressive genetic cardiomyopathy characterised by progressive fatty and fibrous replacement of ventricular myocardium.
Cardiac cells are held less together thus conduction issues.
(cause is unknown)
What inheritance pattern is shown by Arrhythmogenic Right Ventricular Cardiomyopathy?
Familial form is usually autosomal dominant with incomplete penetrance
but can be recessive
Clinical presentation of Arrhythmogenic Right Ventricular Cardiomyopathy
- ARRHYTHMIA is most common feature
- Syncope
- In late stages may be signs of Right heart failure
Diagnosis of Arrhythmogenic Right Ventricular Cardiomyopathy
ECG usually normal but may show T wave inversion
ECHO may also be normal but in advanced disease may show Right ventricular dilation
Genetic testing is the gold standard
Treatment of Arrhythmogenic Right Ventricular Cardiomyopathy
- Beta-blockers e.g. Atenolol for patients with non-life-threatening arrhythmias
- Amiodarone for symptomatic arrhythmias
- Occasionally cardiac transplant indicated i.e. in cardiac failure or devastating arrhythmia
