Cardiomyopathy Flashcards
Define cardiomyopathy.
A group of diseases in which the myocardium becomes structurally and functionally abnormal (in the absence of coronary artery disease, valvular disease and congenital heart disease, drug toxicity etc)
What are the two types of cardiomyopathy?
- Primary: Confined to myocardium
- Secondary: Part of a systemic disease
Who is affected by cardiomyopathy?
Epidemiology: can affect YOUNG patients as well
What are the signs and symptoms of cardiomyopathy?
Symptoms/history:
- Symptoms of HF
- SOB on exertion
- Fainting
- Dizziness
- Fatigue
- Sudden death often 1st presentation
- FH
Signs:
- Signs of HF (resp. crackles, oedema, ↑ JVP)
- Murmurs
- S3
- S4
What investigations may be done for cardiomyopathy?
Investigations: NO single diagnostic test for all types
- Bloods,
- BNP
- CXR,
- ECG,
- Non-invasive stress test- excludes CAD
- ECHO - can differentiate bt different types of cardiomyopathy and is diagnostic for HCM
- Cardiac catheterisation - sometimes used to measure pressure in the left ventricle and aorta. Helps exclude coronary artery disease as cause of dilated cardiomyopathy and distinguishes between restrictive and constrictive
What is dilated cardiomyopathy? What are some causes?
Dilated cardiomyopathy: progressive dilation and contractile dysfunction.
Causes:
- Idiopathic
- Genetic
- Post myocarditis/ post viral
- Alcohol
- Doxorubicin
- Pregnancy
- Haemochromatosis
What are the signs and symptoms of dilated cardiomyopathy?
Symptoms: HF (dyspnoea, fatigue, arrhythmias, ankle swelling, ascites)
Signs:
- Raised JVP
- TR, MR murmur- dilatation of the ventricles leads to significant mitral and tricuspid valve insufficiency and therefore you get TR, MR
- S3
- Displaced apex beat
What would CXR and ECHO show in dilated cardiomyopathy?
- CXR may show a globular heart
- ECHO will show dilated ventricle
Define hypertrophic cardiomyopathy. What are the causes?
Hypertrophic obstructive cardiomyopathy (HOCM) - disproportionate thickening of septal myocardium, disarray and fibrosis.Thickened ventricle may block blood flow out and have poor compliance.
Causes:
50% is familial - autosomal dominant - beta-myosin heavy chain mutation
How can you tell the difference between aortic stenosis and HOCM murmur?
Valsava, Handgrip and squatting manoeuvres can differentiate between the ejection systolic murmurs caused by HOCM and Aortic Stenosis.
What are the signs and symptoms of HOCM?
Symptoms:
- Angina, dyspnea on exertion, palpitations, syncope
- Often sudden cardiac death might be the 1st presentation
Signs:
- Ejection systolic murmur (like in AS)
- Jerky carotid pulse
- Double apex beat
- S4 - atria contract forcefully in an effort to overcome the hypertrophic ventricle.
- Apex beat NOT displaced
Why is there a double impulse in apex in HOCM?
Double impulse in apex: caused by a 2nd impulse after the 1st one from filling of the enlarged ventricle
Pulsus bisfiriens: an aortic waveform with 2 peaks per cardiac cycle
What would you see on ECG and ECHO in hypertrophic cardiomyopathy?
ECG findings:
- Q waves
- Left axis deviation
- Signs of Left Ventricular Hypertrophy: Amir Sam’s LVH by voltage criteria:
- Deep S in V1/2
- Tall R in V5/6
- S in V1 + R in V5 or V6 ≥ 7 large squares
Echo/MRI:
- Ventricular hypertrophy >3cm (asymmetrical septal hypertrophy)
- Diastolic dysfunction
What is the management of HOCM?
Asymptomatic and low risk: observation
If symptomatic but low risk:
- BB - helps with ischaemia symptoms
- CCB - verapamil, diltiazem; avoid in outflow tract obstruction as may worsen it
- Disopyramide - used if there is outflow tract obstruction or symptoms despite BB
If at risk of sudden cardiac death:
- Implantable cardioverter-defibrillator (ICD)
- Avoidance of high-intensity athletics
Other:
- Surgical coronary artery unroofing - helps with ischaemia symptoms
- Surgical myectomy - relieves outflow tract obstruction
What is restrictive cardiomyopathy? What are the causes?
Restrictive cardiomyopathy - ventricles become abnormally rigid and lack the flexibility to expand as the ventricles fill with blood. But there is normal wall thickness and normal/reduced diastolic and systolic volumes.
Causes:
- Idiopathic
- Familial
- Secondary to e.g. radiation, amyloidosis, haemochromatosis, tumour mets
What are the signs and symptoms of restrictive cardiomyopathy?
Symptoms:
- asymptomatic or
- symptoms of HF (dyspnea, fatigue)
Signs (signs of RHF)
- ↑JVP
- Kussmaul’s sign (paradoxical rise in JVP in inspiration due to restricted filling of the ventricles)
- S3
- Ascites, ankle oedema, hepatomegaly
What is the pathophysiology of restrictive cardiomyopathy (Kussmaul’s sign)?
Usually JVP falls with inspiration due to reduced pressure in the expanding thoracic cavity and increased volume allowed for RV expansion.
Kussmaul sign suggests impaired filling of the RV due to poorly compliant myocardium/pericardium
This impaired filling causes increased blood flow back up to the venous system, causing jugular vein distension (JVD) and is seen clinically as the JVP becoming more visible.
What does the ECG/MRI show in restrictive cardiomyopathy?
ECG - bi-atrial hypertrophy and non-specific ST-T wave changes
Cardiac MRI - bi-atrial enlargement, diastolic dysfunction
May need to do myocardial biopsy to distinguish it from constrictive pericarditis.
What is the management of restrictive cardiomyopathy?
Treating the underlying process usually shows no improvement
- Management of heart failure e.g. ACEi
- Arrhythmia management e.g. amiodarone
- Anticoagulation - if AF
- Pacemaker implantation +/- ICD
- Transplantation
A 55-years old man with a heavy history of alcohol abuse presents with breathlessness, which is worse on exertion. He also feels that his heart is racing at times and he complains that his ankles have been swollen. On examination the JVP is increased and the apex beat is displaced. CXR shows a globular heart. Which is the most likely cause of his heart failure?
- A.Myocarditis
- B.Hypertrophic Cardiomyopathy
- C.Dilated Cardiomyopathy
- D.Tricuspid Regurgitation
- E.Amyloidosis.
A.Myocarditis - Signs & Imaging not really consistent
B.Hypertrophic Cardiomyopathy - Apex bear is NOT displaced in hypertrophic cardiomyopathy
C.Dilated Cardiomyopathy
D.Tricuspid Regurgitation - Affects the R side of the heart so apex beat NOT displaced
E.Amyloidosis. - Amyloidosis can lead to dilated (and other types of) cardiomyopathy but is not the SINGLE best answer
A 45-year-old woman complains of increasing shortness of breath on exertion for the previous 3–4 months. She also reports that her ankles have become more swollen during the same time period. She had apparently recovered from pericarditis about a year earlier. CXR shows pericardial calcification. The presumptive diagnosis is constrictive pericarditis. Which of the following signs would be consistent with this diagnosis?
- A.Increased JVP on inspiration
- B.Third heart sound
- C.Fourth heart sound
- D.Inspiratory crackles at lung bases
- E.Loud first and second heart sounds
A.Increased JVP on inspiration - Seen in constrictive pericarditis & restrictive cardiomyopathy
B.Third heart sound - Associated with HF but not pericardial diseases
C.Fourth heart sound - Associated with HF but not pericardial diseases
D.Inspiratory crackles at lung bases - Constrictive pericarditis presents more with RHF signs than LHF
E.Loud first and second heart sounds - S1 and S2 are reduced if anything due to decreased sound transmission through the thickened pericardium
What is the most common cause of sudden death in HOCM?
Outflow obstruction/ cardiac failure / arrhythmia?
Arrhythmia - this is why it is sudden
- Severe thickening of LV increases metabolic demand of muscle whilst moving the subendocardial region further from coronary arterial blood supply on the epicardial surface of the heart.*
- There is also often obstruction to aortic outflow by thickened ventricular septum. Subendocardial region being at the end of the line of blood supply becomes prone to ischaemia.*
What is the genetic inheritance pattern of HOCM?
HCM is an autosomal dominant condition and each child (regardless of sex) has, therefore, a 50% chance of the abnormal gene being passed on to them.
Many are asymptomatic.
What can be done to reduce the risk of sudden cardiac death in HOCM?
An implantable cardioverter-defibrillator can be inserted
