cardiomyopathy Flashcards
what sort of cardiomyopathy does the anthracyclines cause?
restrictive
what is the diagnostic criteria for DCM?
LVEF < 45% and dilated LVEDD (>117% when corrected for age and BSA)
how is fractional shortening calculated?
this is (LVEDD - LVESD) / LVEDD
what CMP phenotype do hypertensive and ischaemic heart disease have?
typically long standing HTN, as well as ischaemia, cause a dilated heart.
however, these have been excluded from the DCM classification in more recent definitions
what are some causes of the DCM?
- tachyarrhythmias
- infectious causes
- nutritional abnormalities
- electrolyte
- endocrine
- infiltrative (incl amyloid, HCM, sarcoid)
- neuromusculars
- toxins, such as HART, amphetamines, clozapine, cocaine
what are the best treatments for dilated cardiomyopathy?
- ACEi - shown to have mortality improvement.
- diuretics for symptomatic pulm vessel congestion
- beta blockers - standard of care
- CRT - if LVEF < 30 - 45%; LBBB (QRS > 120 - 150 depending on study) on ECG
what are the indications for ICD therapy in DCM?
- VT/VF arrest
- spontaneous sustained VT
- syncope of uncertain origin
- VT/VF at EPS
- LVEF 1 year
what role do VAD play?
ventricular assist devices are really only as a bridge to transplant.
they are not, currently, suitable as destination therapy
what is the genetics of HCM?
this is a disease of the sarcomere
it is AD
many different abnormalities, with variable penetrance
What are the most common causes of sudden death in young athletes in the US
most common:
- HCM (~35%!)
- congenital coronary artery anomaly
less common
- myocarditis
- aortic rupture (Marfan)
- MVP
uncommon:
- ARVC
- CAD
- conduction system abnormalities
- aortic valve stenosis
what happens with HCM on echo?
- there is systolic anterior movement of the anterior leaflet of the mitral valve
- there is dynamic LVOT obstruction (depends on afterload, preload, contractility) (this is only about 25% of patients, however)
- MR occurs secondary to the aortic leaflet movement
- diastolic dysfunction is an important finding. this is because the LV is stiff. This leads to elevated LVEDP, elevated LA pressure and elevated pulm pressures
What are the clinical findings in HCM?
examination?
ECG?
examination has a systolic murmur, that is quieter on squatting and louder with standing
ecg is abnormal in about 95%. usually LVH with repol abnormalities
how do we diagnose HCM?
DNA analysis is actually Gold Standard, however there is a bit of a miss rate with genetic screen (not all abnormalities have been identified)
2D echo can demonstrate the anatomy - 90-95% see asymmetric hypertrophy, the rest see concentric
Doppler echo shows the pathophysiology such as LVOT, MR, diastolic dysfunction
what are some of the RF for sudden cardiac death in the HCM population?
high risk features:
- prior cardiac arrest or spont sustained VT
- FH of prematured HCM-related SCM
- syncope
- repetitive bursts of nsVT on Holter
- hypotension on response to exercise
- extreme LVH > 30mm
what is the role of septal ablation in HCM?
it is used to cause a localised infarct and reduce a LVOT obstruction
(they introduce alcohol down a small coronary artery)
what does the echo normally look like with restrictive cardiomyopathy?
usually we have normal or reduced ventricular volumes, normal or near normal systolic function, significant atrial dilatation
the pathophysiology is dominated by diastolic filling abnormalities
what is ARVC?
likely AD, progressive fibrofatty replacement of right myocardium, initially RV, then LV with relative sparing of the septum
it is diagnosed based on major and minor criteria
it is associated with many presentations, including arrhythmias and also heart failure
what are some of the findings on ECG for ARVC?
Epsilon waves are important, and they are associated with low amplitude signals between QRS and T wave
there can also be LBBB on nsVT etc
what is the best clinical predictor of sudden cardiac death?
previous arrest, probably
syncope is stronger than LVEF <25% and ECG changes
what is the most specific finding for HCM on echo?
asymmetrical wall thickening is probably number 1
