Cardiomyopathy Flashcards
What is a cardiomyopathy and what can it lead to?
Disease of heart muscle making it harder to pump blood to body
can lead to heart failure
What main types of cardiomyopathy are there?
Dilated
Hypertrophic
Restrictive
What is dilated cardiomyopathy?
progressive
usually irreversible
causing contractile dysfunction with heart failure
What are the causes of dilated cardiomyopathy?
25% familial
secondary causes : heart valve disease
after child birth
thyroid disease
myocarditis alcoholism autoimmune ingestion of drugs mitocondrial disorders
What is the pathophysiology of dilated cardiomyopathy?
Enlarged L ventricle
–> lower EF, increase in V wall stress and ESV
What are the early compensatory mechanisms in dilated cardiomyopathy?
increase in heart rate and tone of peripheral vascular system
What hormones or peptides increase in circulation due to dilated cardiomyopathy?
Neurohumoral activation of renin-angiotensin aldesterone system and an increase in CATECHOLAMINES in system
levels of NATRIURETIC peptides
these increase as part of the compensatory mechanisms however these can become overhwlemed and heart will fail
How will a person with dilated myopathy present?
Dyspnoea Murmur Fatigue angina pulmonary congestion low cardiac output displaced apex beat, S3 or systolic
What investigations are done for dilated cardiomyopathy?
Genetic (familail) viral serology ECG chest C ray Cardiac cathetar cardiac MRI/CT exercise stress test echocardiography
What diet modifications should be made for dilated myopathy?
Fluid and Na+ restriction
If the underlying cause of dilated cardiomyopathy is sarcoidosis / myocarditis what treatment is given?
Immunosuppressants
If the underlying cause of dilated cardiomyopathy is haemochromatosis what treatment is given
Phlebotomy
When would you lower ACE inhibitor dose for heart failure?
If the px develops cough, hypertension, renal dysfunction
Wha is given for arrhythmias based on dilated cardiomyopathy?
Amiodarone
Dofetillide
What is hypertrophic cardiomyopathy?
Increase in left ventricular wall thickness that is not solely explained by abnormal loading conditions
Genetic - autosomal dominant in 50% of cases
Why is hypertrophic cardiomyopathy the leading cause of sudden cardiac death in children and adolescents?
Most px are asymptomatic however this means the first clinical manifestation may be sudden death from ventricular tachycardia or fibrillation
Where does the hypertrophy usually occur in the left ventricle?
Although it can occur in any region of LV
usually involved interventricular septum which obstructs the flow of blood from smaller LV to the aorta
How is the diastolic function in hypertrophic cardiomyopathy px?
abnormal function, impairs ventricular filling and increases filling pressure
these px have abnormal calcium kinetics, subendocardial ischaemia
How may a px with hypertrophic cardiomyopathy present?
- Sudden cardiac death
- S3
- ejection systolic murmur
- Gallop
- Syncope
- presyncope
- congestive heart failure
- dizziness
- palpitations
- angina
What investigations are done hypertrophic cardiomyopathy?
Haemoglobin levels - anaemia worsens chest pain and dyspnea
Brain natriuretic peptide (BNP), troponin T levels: Elevated BNP, NT-proBNP, and troponin T levels are associated with a higher risk of cardiovascular events, heart failure, and death
Echocardiography
Chest Xray
Cardiac MRI
How is HCM managed?
The symptoms are managed with B blocker, the side effects of which are reduced by verapamil
add disopyramide if symptoms persist
if there are refactory symptoms then undergo mechanical therapy
What mechanical treatments are avaliable for HCM?
?PM with short AV delay
if further invasive is required due to refractory symptoms –> Septal myectomy or ablation
What is restrictive cardiomyopathy?
diagnosis is based on establishing the presence of restrictive ventricular filling
characterized by:
-diastolic dysfunction with restrictive ventricular physiology
- systolic function remains normal.
- Atrial enlargement occurs due to impaired ventricular filling during diastole
- but the volume and wall thickness of the ventricles are usually normal.
What may cause RCM?
idiopathic, familial (has been related to troponin I or desmin mutations, the latter often in association with a skeletal myopathy),
systemic disorders: - haemochromatosis, - amyloidosis - sarcoidosis - Fabry's disease - carcinoid syndrome - scleroderma, anthracycline toxicity or previous radiation.
