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
Describe the appearance of this heart.
- Marked hypertrophy of the LV
- Disorganised arrangement of hypertrophied cardiac muslce = HCM/HOCM
LV hypertrophy may be asymmetric (more thickening in septum, than free wall) but is usually symmetric (concentric) and affects full circumference of LV.
Define dilated cardiomyopathy.
LV dilatation and systolic dysfunction in absence of abnormal loading or significant CAD
What is the aetiology of dilated cardiomyopathy?
- idiopathic: the most common cause
- myocarditis: e.g. Coxsackie B, HIV, diphtheria, Chagas disease
- Wet beri beri (thiamine/B1 deficiency)
- ischaemic heart disease
- peripartum
- hypertension
- iatrogenic: e.g. doxorubicin
- substance abuse: e.g. alcohol, cocaine
- inherited (35%): either a familial genetic predisposition to DCM or a specific syndrome e.g. Duchenne muscular dystrophy
- infiltrative e.g. haemochromatosis, sarcoidosis
What is the pathophysiology of dilated cardiomyopathy?
- Predominately systolic dysfunction
- All 4 chambers are dilated, but the LV > RV
- Eccentric hypertrophy (sarcomeres added in series) is seen
What are the clinical features of dilated cardiomyopathy?
- Heart failure symptoms
- Systolic murmur: stretching of the valves may result in mitral and tricuspid regurgitation
- S3
- ‘Balloon’ appearance of the heart on the chest x-ray
What is the management of dilated cadiomyopathy?
Treat symptoms and prevent complications of HF
+/- ICD
+/- Mitral annuloplasty or valve replacement
+/- Catheter ablation of arrhythmias
What is the prognosis with dilated cardiomyopathy?
Depends on initial presentation
5yr survival is ~50%. MR or diastolic dysfunction is associated with a worse prognosis.
What is arrhythmogenic right ventricular cardiomyopathy? What is the cause and how does it present?
ARVC - There is progressive replacement of the myocardium with fatty and fibrous material, usually around the apex.
Aetiology - inherited (AD)
Presentation - asymptomatic initially , may present with arrhythmias especially during exercise. May have hair and skin changes e.g. Naxos disease
What is the pathophysiology of AVRC?
AD pattern of inheritance
RV myocardium replaced by fatty and fibrofatty tissue
~50% have a mutation of genes which encode desmosomes
What do investigations show in ARVC?
ECG - T wave inversion in V1-3, epsilon wave in 50% of cases (i.e. terminal notching in the QRS complex)
Echo - enlarged, hypokinetic RV with thin free wall
MRI - useful to show fibrofatty tissue
What is the management of ARVC?
- Anti-arrhythmics - sotalol is the most widely used antiarrhythmic
- Catheter ablation - to prevent ventricular tachycardia
- ICD
Name 2 features of Naxos disease.
- AR variant of ARVC
- Triad of:
- ARVC,
- palmoplantar keratosis,
- woolly hair
Name the different aetiologies of cardiomyopathies and a specific cause of each e.g. infective etc
What are some risk factors for peripartum cardiomyopathy?
- Develops between last month of pregnancy-5months post-partum
- Older women
- Greater parity
- Multiple gestations
Define Takotsubo cardiomyopathy.
Takotsubo cardiomyopathy is a type of non-ischaemic cardiomyopathy associated with a transient, apical ballooning of the myocardium. It may be triggered by stress.
AKA broken heart syndrome
What is the pathophysiology of Takotsubo cardiomyopathy?
NOT inherited
Apical ballooning due to severe hypokinesis of the mid-apical segments of the ventricle, with preservation of activity in the basal (top) segments
This creates the shape of an octopus trap
Ventricular wall may appear weakened on TTE/MRI
What are the clinical features of Takotsubo cardiomyopathy?
- Sudden intense chest pain
- SOB
- Palpitations
- Nausea/vomiting
- Features of heart failure
- ECG: ST-elevation
- normal coronary angiogram
What is the management of Takotsubo cardiomyopathy?
Supportive treatment:
- Diuretics
- BB/ACEi
- Anticoagulants - if AF
What is the prognosis with Takotsubo cardiomyopathy?
Most improve with supportive treatment
Reversible
What are the triggers for Takotsubo cardiomyopathy?
Extreme emotional or physical stress
Who is most affected by Takotsubo cardiomyopathy?
Postmenopausal women
Higher prevalence in Japan
2000-3000 cases per year in UK
