Cardiomyopathies Flashcards
What is cardiomyopathy
disease of heart muscle making it difficult for heart to pump to the rest of the body. Can lead to heart failure
Types of cardiomyopathy
Dilated
Hypertrophic
Restrictive
What is dilated cardiomyopathy? (DCM)
Ventricular chamber enlargement (>4cm) and systolic dysfunction
Primary causes of dilated cardiomyopathy
Genetics
Idiopathic (w/o FH)
What are some secondary causes of dilated cardiomyopathy?
MI, Heart valve disease, thyroid disease, myocarditis, alcoholism, autoimmune
Pathophysiology of dilated cardiomyopathy
Damage/death of myocytes (inflamm/toxic)
Eccentric fibrosis + vol ^
LV enlargement w/o ^ muscle mass due to fibrosis of the muscles
initially contractility is ok (frank-starling law)
Gradual over distension and systolic dysfunction
red. CO + ^EDV/EDP
Vol overload and congestive heart failure
Why does DCM lead to dyspnoea and cold, clammy extremities
red CO -> insufficient tissue O2
Why is there a displaced apex beat in DCM
Enlarged left ventricle
Why would a px with DCM experience fatigue
red CO/organ perfusion
What causes angina in cardiomyopathy
low coronary perfusion
What is a sign of pulmonary congestion
diffuse crackles
What can heart failure lead to
Pulmonary oedema
What is the presentation of dilated cardiomyopathy?
Dyspnoea, displaced apex beat, fatigue, angina, pulmonary congestion, low cardiac output
Investigations for the diagnosis of dilated cardiomyopathy
ECG
CXR
cardiac MRI/CT
Cardiac catheterisation
Echocardiography
What investigations would you carry out if you suspected familial/viral cause of dilated cardiomyopathy
Genetic testing
viral serology
What are the main types of management in dilated cardiomyopathy
counselling - irreversible
Alleviate the cause
Symptom relief
What are the general areas of treatment for dilated cardiomyopathy?
Diet (fluid and Na+ restriction),
treat underlying conditions (immunosuppressants),
heart failure symptoms (ACE-i, beta blockers),
treat arrhythmias (atrial fibrillation),
thromboembolic events (anticoag)
What is hypertrophic cardiomyopathy? (HCM)
Genetic CVD
^ LV wall thickness / interventricular septum thickness -> obstruction of flow through left ventricle
Why does hypertrophic cardiomyopathy cause sudden death?
Often asymptomatic, first clinical presentation is ventricular fibrillation
Pathophysiology of HCM
Genetic disease/disorders -> thickened LV myocardium/septum -> obstruction of flow
Disorganised myocytes disrupt signal conduction
Ventricular arrhythmia
Sudden cardiac death
How does HCM present?
Sudden cardiac death, syncope, congestive heart failure, S4 sound, angina, ejection systolic murmur
Why is there an S4 sound in HCM
Forceful atrial contraction into hypertrophic LV
What causes syncope in HCM
red. CO to peripheries and head
Why does a px with HCM feel fatigue
low CO and red. organ perfusion
Why is a systolic murmur heard in HCM
Impaired passage of blood through to aorta
Investigations to diagnose HCM
Echocardiogram
CXR
Cardiac MRI
How would you manage HCM initially?
Beta blocker, verapamil if contraindicated
What is the more severe management of HCM?
Mechanical therapy - pacemaker, septal myectomy or ablation (remove part of septum)
What is restrictive cardiomyopathy? RCM
Rigid heart muscles restricts heart stretch/ventricular filling
Describe the pathophysiology of restrictive cardiomyopathy
Deposition of abnormal substances (amyloids proteins, noncaseating granulomas) in heart tissue,
Infiltrates ventricular walls ->fibrosis/stiffening -> diastolic dysfunction.
Atrial enlargement in response
conductive abnormalities -> diastolic heart failureW
What can advanced restrictive cardiomyopathy lead to
Adverse remodelling -> systolic dysfunction/ ventricular arrhythmias
What causes ascites and peripheral pitting oedema in RCM
^ venous pressure -> right sided heart failure
(back pressure into systemic veins)
Why is there hepatomegaly in RCM
Hepatic congestion due to RHF
Why is S4 heard in RCM
atrium contracts to pump blood into stiff ventricle
Why is there an increase in JVP in RCM
RHF means greater pressure in the veins
What is the presentation of restrictive cardiomyopathy?
congestion (fluid in abdomen and lungs),
hepatomegaly,
increased jugular venous pressure,
reduced Pulse/SV/CO
Investigations for the diagnosis of RCM
Serology
Amyloidosis check
CXR
ECG
Echocardiography
MRI
What are the 5 management techniques for restrictive cardiomyopathy?
Heart failure meds,
antiarrhythmic therapy,
immunosuppression (steroids),
pacemaker,
cardiac transplantation
