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.
