Cardiomyopathies Flashcards
Define cardiomyopathy [1]
‘A myocardial disorder in which the heart muscle is structurally and functionally abnormal, in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to cause the observed myocardial abnormality’
FYI
The old classification of dilated, restricted and hypertrophic cardiomyopathy has been largely abandoned due to the high degree of overlap. The latest classification of cardiomyopathy by the WHO and American Heart Association reflect this.
Describe the typical ECHO findings for dilated, restrictive and HOCM [3]
Dilated:
- Decreased LV thicknesss
- Ejection fraction decrease
HOCM:
- Hypertrophoed LV
- LVOT
- LVEF normal or raised
Restrictive:
- Enlarged right atrium
- LVEF reduced
- Infiltrated disordes: speckled apperance
State 4 classical causes of dialted cardiomyopathy [4]
Alcohol
Coxsackie B virus
Wet beri beri (thiamine deficiency)
Doxorubicin
State three classical causes of restrictive cardiomyopathy [3]
Amyloidosis
Post-radiotherapy
Loeffler’s endocarditis
Name two acquired cardiomyopathies [2]
peripartum cardiomyopathy
takotsubo cardiomyopathy
At which stage of pregnancy does peri-partum cardiomyopathy usually occur [1] and go on till? [1]
Which subpopulations of pregnant women usually suffer from peripartum cardiomyopathy? [2]
peri-partum cardiomyopathy:
- last month of pregnancy and 5 months post-partum
- usually older; greater parity and multiple gestations
The following indicates what type of cardiomyopathy? [1]
patient just found out family member dies then develops chest pain and features of heart failure
Takotsubo cardiomyopathy
Name two infective organisms that can cause cardiomyopathy [2]
Coxsackie B virus
Chagas diesease
State a disorder of disturbed mineral balance that can cause cardiomyopathy [1]
Haemochromatosis
State two causes of cardiomyopathy that arise from drug toxicity [2]
Alcohol induced
Doxorubicin
State three endocrine disorders that dispose patients to cardiomyopathy [3]
DM
Thyrotoxicosis
Acromegaly
State three neuromuscular disorders that dispose patients to cardiomyopathy [3]
Friedreich’s ataxia
Duchenne-Becker muscular dystrophy
Myotonic dystrophy
State a nutrional deficiency that disposes patients to cardiomyopathy [1]
Beriberi (thiamine)
State an autoimmune disorders that dispose patients to cardiomyopathy [1]
SLE
State an inflammatory disorder that dispose patients to cardiomyopathy [1]
Sarcoidosis
Define HOCM [1]
Describe the pathophysiology of HOCM
HOCM: is defined as increased ventricular wall thickness or mass not caused by pathologic loading conditions.
Pathophysiology:
- mutation in the gene encoding β-myosin heavy chain protein or myosin-binding protein C
- This results in predominantly diastolic dysfunction:
- left ventricle hypertrophy → decreased compliance → decreased cardiac output
Explain the clinical consequences of HOCM [5]
Myocardial hypertrophy:
- predominantly in the interventricular septum
- asymmetric septal hypertrophy narrows the left ventricular outflow tract (LVOT).
Diastolic dysfunction:
- Reduced compliance and elevated filling pressures ddue to hypertrophy
LVOT obstruction:
- The interventricular septal hypertrophy, combined with systolic anterior motion (SAM) of the mitral valve, causes dynamic obstruction of the LVOT during systole.
- This increases the pressure gradient across the LVOT, reducing cardiac output and provoking symptoms.
Mitral regurgitation:
- The SAM of the mitral valve contributes to mitral regurgitation by displacing the valve leaflets, exacerbating the hemodynamic abnormalities and worsening heart failure symptoms
Arrhythmogenesis:
- Myocardial disarray, fibrosis, and ischemia increase the risk of ventricular and atrial arrhythmias
- can lead to sudden cardiac death.
Describe what is meant by systolic anterior motion of the mitral valve [1]
Movement of the mitral valve anteriorly during systole: known as systolic anterior motion of the mitral valve due to hypertrophy of the interventricular septum
Describe a typical presentatio of HOCM [3]
Most patients are asymptomatic
Other patients may present with features of heart failure, arrhythmias or cardiac arrest.
Patients often have sudden cardiac arrests
Describe the typical signs seen in HOCM patient [7]
Ejection systolic murmur (left ventricular outflow obstruction):
- harsh crescendo-decrescendo shortly after S1 and loudest at the apex and lower left sternal edge
Mid-late systolic murmur (mitral regurgitation):
- occurs at the apex. Depending on the extent of mitral regurgitation and the direction of the jet regurgitating through the mitral valve it may be pansystolic
S4 gallop:
- This can be heard in patients with impaired diastolic function, reflecting atrial contraction against a noncompliant left ventricle.
Heave (visible or palpation pulsation)
Thrill (palpable murmur)
Features of heart failure:
- raised JVP, crackles on lung auscultation, peripheral oedema
Bifid carotid pulse:
- A rapid upstroke followed by a mid-systolic dip may be observed, known as the ‘spike and dome’ pulse.
Increased left ventricular wall thickness ≥[] mm in the absence of any other identifiable cause is consistent with HCM
Increased left ventricular wall thickness ≥15 mm in the absence of any other identifiable cause is consistent with HCM
Name and describe the results seen in th 1st investigations to order for suspected HOCM? [3]
BMJ BP
ECG:
- Deep, narrow (“dagger-like”) Q waves in lateral (I, aVL, V5-6) +/- inferior (II, III, aVF) leads
- LVH (present with QRS complexes that are tallest in the midprecordial leads): deep T wave inversion in I, II, VL & V3-6
- ST-T wave abnormalities;
- normal
CXR:
- cardiomegaly
- normal
echocardiography
- cardinal feature is left ventricular hypertrophy (LVH)
- asymmetric septal hypertrophy
How would an ECG indicate HOCM? [3]
Left ventricular hypertrophy (LVH)
T-wave inversions:
- Deep, symmetric T-wave inversions in the precordial leads are suggestive of HOCM.
Arrhythmias:
- Atrial fibrillation or ventricular tachycardia may be detected.
Which imaging modality can be usefull to differentiate HOCM from other causes of LVH? [1]
Cardiac Magnetic Resonance Imaging (CMR): provides detailed assessment of myocardial hypertrophy, fibrosis (using late gadolinium enhancement), and ventricular function.
Describe the medical managment plan for a patient with HOCM used to reduce symptoms and LVOT obstruction [5]
A. Beta blockers
- 1st line: atenolol or propranolol
B. CCBs:
- Verapamil
C. antiarrhythmic agents:
- Disopyramide
D. Diuretics:
- furosemide
- Caution is warranted due to the potential for hypovolemia and exacerbation of LVOT obstruction.
E. Anticoagulation:
- Indicated in patients with atrial fibrillation or a history of thromboembolic events.
Describe the surgical managment that can be given for severe, symptomatic LVOT obstruction refractory to medical therapy? [2]
Septal myectomy:
- Surgical removal of a portion of the hypertrophied septum, with a low operative mortality rate and durable long-term symptomatic relief.
Alcohol septal ablation
- A percutaneous approach, involving injection of ethanol into a septal coronary artery to induce localized myocardial infarction and septal thinning.
- Outcomes are comparable to septal myectomy but may be less effective in patients with extreme septal thickness.
Which patients may be indicated to have an ICD with HOCM? [4]
- A history of cardiac arrest or sustained ventricular arrhythmias.
- Family history of sudden cardiac death.
- Unexplained syncope.
- Severe LVH or marked LVOT obstruction.
Arrhythmogenic cardiomyopathy is a genetic condition where the heart muscle is progressively replaced with fibrofatty tissue
Which type of arrhythmias are common? [1]
ventricular arrhythmias
Describe the hypotheses behind the pathophysiology of Takotsubo cardiomyopathy [5]
Catecholamine-Induced Myocardial Stunning:
- excessive catecholamine release during acute stress, such as adrenaline or noradrenaline cause direct myocardial injury and myocardial stunning through Ca2+ overload; myocardial microvascular spasm or beta receptor desensitisation
Coronary Microvascular Dysfunction:
- dysfunction of the coronary microcirculation leads to myocardial ischemia, resulting in the characteristic regional wall motion abnormalities observed in TCM
Multi-Vessel Coronary Artery Vasospasm:
- transient, multi-vessel coronary artery vasospasm, leading to transient myocardial ischemia.
Neurogenic Stunning:
- cardiac dysfunction occurs due to an acute central nervous system (CNS) injury or dysfunction.
Role of Oestrogen Deficiency:
- Oestrogen has been shown to have cardioprotective effects, including vasodilation, anti-inflammatory actions, and antioxidant properties.
- higher prevalence of TCM in postmenopausal women suggests that oestrogen deficiency may contribute to the development of the condition.
Describe the heart changes seen in TM
characteristic apical ballooning with transient systolic dysfunction
Which differentials should you think of when investigating TCM? [3]
Requires the exclusion of other potential causes, such as acute coronary syndrome (ACS), myocarditis, and pheochromocytoma
The gold standard for diagnosis of TCM is [], which helps rule out obstructive CAD.
The gold standard for diagnosis is coronary angiography, which helps rule out obstructive CAD.
How do you manage TCM? [1]
The management of TCM is primarily supportive, as the condition is generally self-limiting and resolves within weeks.
Which specific type of cardiomyopathy is the most well characterised arrhythmogenic cardiomyopathy caused by a genetic mutation? [1]
Arrhythmogenic right ventricular cardiomyopathy (ARVC) is the most well characterised ACM caused by a genetic mutation.
Classic causes of which type of cardiomyopathy are amyloidosis, haemochromatosis (iron overload) and sarcoidosis
Dilated cardiomyopathy
Arrhythmogenic cardiomyopathy
Takotsubo’s cardiomyopathy
Restrictive cardiomyopathy
Classic causes of which type of cardiomyopathy are amyloidosis, haemochromatosis (iron overload) and sarcoidosis
Dilated cardiomyopathy
Arrhythmogenic cardiomyopathy
Takotsubo’s cardiomyopathy
Restrictive cardiomyopathy
This image shows
Dilated cardiomyopathy
Hypertrophic Obstructive Cardiomyopathy
Arrhythmogenic cardiomyopathy
Takotsubo’s cardiomyopathy
Restrictive cardiomyopathy
Dilated cardiomyopathy: note the large ventricles and thin walls
This image shows
Dilated cardiomyopathy
Hypertrophic Obstructive Cardiomyopathy
Arrhythmogenic cardiomyopathy
Takotsubo’s cardiomyopathy
Restrictive cardiomyopathy
This image shows
Dilated cardiomyopathy
Hypertrophic Obstructive Cardiomyopathy
Arrhythmogenic cardiomyopathy
Takotsubo’s cardiomyopathy
Restrictive cardiomyopathy
Describe the wall changes seen in retrictive cardiomyopathy [3]
This shows evidence of non-dilated, non-thickened ventricles with abnormal ventricular filling, features of diastolic dysfunction and usually atrial enlargement.
Describe why HOCM causes a crescendo-decresendo heart murmur [1]
Haemochromatosis causes
Dilated cardiomyopathy
Hypertrophic Obstructive Cardiomyopathy
Arrhythmogenic cardiomyopathy
Takotsubo’s cardiomyopathy
Restrictive cardiomyopathy
Haemochromatosis causes
Dilated cardiomyopathy
Hypertrophic Obstructive Cardiomyopathy
Arrhythmogenic cardiomyopathy
Takotsubo’s cardiomyopathy
Restrictive cardiomyopathy
Loffler syndrome is when eiosinophils infiltrate lung tissue. This can turn into Loffler’s endocarditis, where they are found in endocardium. This typically causes
Dilated cardiomyopathy
Hypertrophic Obstructive Cardiomyopathy
Arrhythmogenic cardiomyopathy
Takotsubo’s cardiomyopathy
Restrictive cardiomyopathy
Loffler syndrome is when eiosinophils infiltrate lung tissue. This can turn into Loffler’s endocarditis, where they are found in endocardium. This typically causes
Dilated cardiomyopathy
Hypertrophic Obstructive Cardiomyopathy
Arrhythmogenic cardiomyopathy
Takotsubo’s cardiomyopathy
Restrictive cardiomyopathy
Heart tissue radiation generally causes:
Dilated cardiomyopathy
Hypertrophic Obstructive Cardiomyopathy
Arrhythmogenic cardiomyopathy
Takotsubo’s cardiomyopathy
Restrictive cardiomyopathy
Heart tissue radiation generally causes:
Dilated cardiomyopathy
Hypertrophic Obstructive Cardiomyopathy
Arrhythmogenic cardiomyopathy
Takotsubo’s cardiomyopathy
Restrictive cardiomyopathy
What is a good pneumonic for learning causes of restrictive CM? [5]
What is the management for HOCM? [5]
Management:
Amiodarone
Beta-blockers or verapamil for symptoms
Cardioverter defibrillator
Dual chamber pacemaker
Endocarditis prophylaxis*
Which drug classes should be avoided in HOCM patients? [3]
nitrates
ACE-inhibitors
inotropes
How can you elicit a louder [1] and quieter [1] murmur for a patient with HOCM? [1]
HOCM may present with ejection systolic murmur, louder on performing Valsalva and quieter on squatting
Describe what is meant by Arrhythmogenic right ventricular cardiomyopathy
Form of inherited cardiovascular disease which may present with syncope or sudden cardiac death:
* inherited in an autosomal dominant pattern with variable expression
* the right ventricular myocardium is replaced by fatty and fibrofatty tissue
* around 50% of patients have a mutation of one of the several genes which encode components of desmosome
[] is generally regarded as the second most common cause of sudden cardiac death in the young after hypertrophic cardiomyopathy.
Arrhythmogenic right ventricular cardiomyopathy
How would you investigate arrhythmogenic right ventricular cardiomyopathy? [3]
- ECG abnormalities in V1-3, typically T wave inversion. An epsilon wave is found in about 50% of those with ARV - this is best described as a terminal notch in the QRS complex
- echo changes are often subtle in the early stages but may show an enlarged, hypokinetic right ventricle with a thin free wall
- magnetic resonance imaging is useful to show fibrofatty tissue
How do you manage arrhythmogenic right ventricular cardiomyopathy? [3]
Management
* drugs: sotalol is the most widely used antiarrhythmic
* catheter ablation to prevent ventricular tachycardia
* implantable cardioverter-defibrillator
