cardiomyopathy (see DM)

Question 1

what is a cardiomyopathy

Answer 1

a disorder in which heart muscle is structurally and functionally abnormal

Question 2

what are the 2 common types of cardiomyopathies

Answer 2

hypertrophic cardiomyopathy; dilated cardiomyopathy

Question 3

what are the 2 less common types of cardiomyopathies

Answer 3

arrythmogenic right ventricular cardiomyopathy; restrictive cardiomyopathy

Question 4

what is hypertrophic cardiomyopathy

Answer 4

unexplained hypertrophy, most often affecting the wall between two ventricles; diastolic abnormality; usually asymmetrical (symmetrical may be due to AS/MR); bulges into LV overflow tract

Question 5

what is dilated cardiomyopathy

Answer 5

stretching and weakening of the heart muscle, usually starts in the LV; systolic abnormality

Question 6

what is arrythmogenic right ventricular cardiomyopathy

Answer 6

an inherited disease where fat and scar tissue (fibrofatty tissue) replace muscle in the right ventricle

Question 7

what is restrictive cardiomyopathy

Answer 7

stiffening of the ventricle walls

Question 8

what is the commonest cause of sudden cardiac death in <35yro

Answer 8

hypertrophic cardiomyopathy

Question 9

what kind of dominance does HCM have

Answer 9

autosomal dominant mutations in genes that code for sarcomere components

Question 10

brief pathophys of HCM

Answer 10

mutant peptides incorporated into sarcomere -> bad contraction -> hypertrophy to compensate

Question 11

muscle cell organisation in HCM

Answer 11

disarray; hypertrophied

Question 12

what is hypertrophic obstructuve cardiomyopathy (HOCM)

Answer 12

obstructive form of HCM where the outflow tract is blocked due to the anterior leaflet of the MV veing dragged over towards the lateral wall, blocking the outflow of blood from the LV; leads to MR and irregular/jumping pulse

Question 13

myofibre disarray pathway to symptoms

Answer 13

myofibre disarray -> ventricular arrhythmias e.g. re-entry due to hypertrophic cells having diff electrical properties -> syncope, sudden death

Question 14

LVH to symptom pathway (2)

Answer 14

1. LVH ->impaired relaxation -> increased LVEDP -> SOB;
2. LVH -> increased myocardial O2 demand -> chest pain

Question 15

LV outflow obstruction to symptom pathway (3)

Answer 15

1. obstruciton -> incr systolic pressure -> incr 02 myocardial demand -> chest pain;
2. obstruciton -> mitral regurg -> SOB
3. obstruciton -> failure to incr CO during exertion -> syncope

Question 16

4 main parts to management of HCM

Answer 16

1. education and reassurance;
2. risk stratification for sudden cardiac death;
3. management of symptoms and complications;
4. family screening

Question 17

when is an ICD recommended for HCM

Answer 17

of there has been a prior CVD event e.g. sustained VT

Question 18

what drug is given for HCM

Answer 18

BBs or verapamil - decr HR and force of contraction -> incr diastolic filling time, decr myocardial O2 demand

Question 19

what is mavacamten

Answer 19

a targeted inhibitor of cardiac myosin (reduces cross bridges) that improves symptoms in HOCM

Question 20

what are 2 main complications o HCM and how are they managed

Answer 20

1. AF - often poorly tolerated due to loss of atrial contribution to diastolic filling, anticoagulate, rate/rhythm control;
2. HF - drugs or myomectomy improve symptoms, if refractory HF symptoms refer for transplant

Question 21

what should be offered to first degree relatives

Answer 21

genetic counselling; cascade family screening; regular ECG and echo (if no mutation found)

Question 22

4 compensatory mechs of dilated cardiomyopathy

Answer 22

neurohormonal activation; sympathetic nervse upregulated; ADH release; RAAS downreg

Question 23

brief pathophys of dilated cardio myopathy (3)

Answer 23

1. myocyte injury -> decr contractility -> decr SV -> incr ventricular filling pressure -> pulmonary congestion + systemic congestion;
2. myocyte injury -> decr contractility -> decr SV -> LV dilation -> mitral regur -> LV dilation etc.
3. myocyte injury -> decr contractility -> decr SV -> decr forward CO

Question 24

6 main causes of DCM

Answer 24

1. idiopathic
2. genetic (familial, neuromuscular)
3. inflammatory (infectious, non infectious)
4. toxic
5. metabolic
6. tachy induces (arryhtmias)

Question 25

what is the management of DCM the same as?

Answer 25

management of HFrEF (ACEi, BB, MRA, SGLT2i, loop diuretic)

Question 26

what does ACM predispose the heart to

Answer 26

ventricular arrythmias and impaired contraction

Question 27

what area is most commonly affected in ARCV

Answer 27

right ventricle

Question 28

what cellular structure does ARVC affect and how

Answer 28

desmosomes (binds muscle cells together); muscle cells die when they are not attached to each other and this dead tissue is replaced by fat and scar tissue

Question 29

ARVC ECG abnormality

Answer 29

T wave inversion in V1-3; localised prolongation of QRS complex in V1-3; LBBB VT is a common arrythmia seen

Question 30

what are the 3 clinical phases associated with ARVC

Answer 30

1. concealed phase (asymptomatic but still at risk of sudden cardiac death);
2. electrical phase (symptomatic ventricular arrhythmia);
3. advanced phase (characterised by RV/biventricular failure)

Question 31

4 aspects of ARVC management

Answer 31

risk stratification for sudden cardiac death (ICD); improve symptoms and QoL (HF/aarythmias); Prevent disease progression (exercise restriction); cascade screening of fam members (autosomal dominant mutation)

Question 32

restrictive cardiomyopathy rigid myocardium to symptoms pathway (2)

Answer 32

1. rigid myocardium -> incr diastolic ventricular pressure -> venous congestion -> JVP distention, hepatomegaly and ascites, peripheral oedema;
2. rigid myocardium -> decr ventricular filling -> decr CO -> weakness, fatigue

Question 33

what can cause restrictive cardiomyopathy

Answer 33

myocardial fibrosis or infiltration (e.g by amyloid)

Question 34

what is Takotsubo’s cardiomyopathy

Answer 34

broken heart syndrome; often brought on by stress (usually acute and severe); Symptoms and signs may mimic MI; self limiting condition but there is a risk of sudden death due to arrhythmia or
ventricular free-wall rupture