Inherited cardiac conditions

Question 1

What is hypertrophic cardiomyopathy?
What is the prevalence?
Why is diastolic function impaired?
ECG changes in HCM?

Answer 1

Hypertrophic cardiomyopathy (HCM) is a disease in which the heart muscle becomes abnormally thick (hypertrophied). 
As the ventricle hypertrophies, it encroaches on the cavities and doesn't allow the heart to fully relax after contraction = systolic contraction is very powerful but diastolic function is impaired. 
Prevalance = 0.2%. (1 in 500)
- 70% have changes in actin and myosin, autosominal dominant inheritance. 

ECG changes

• Very large QRS complex (due to large ventricles)
• Progressive T wave inversion
• AF
• WPW syndrome
• VT can occur

Question 2

What is a dilated cardiomyopathy?
Signs and symptoms?
Treatment?

Answer 2

Dilatation of the ventricles causing a flabby heart and sometimes thinned walls.

• Commonly genetic
• prevalence 0.2%
• Affects contraction of the heart

Signs of DCM (not in lecture)

• Increased pulse
• Hypotension
• Increased JVP
• Displaced and diffuse apex
• S3 gallop
• Mitral or tricuspid regurgitation
• Pleural effusion, oedema, jaundice, hepatomegaly, ascites

Presentation of DCM (not. in lecture)

• Fatigue
• Dyspnoea
• Pulmonary oedema
• RVF
• AF
• VT

Treatment of DCM

• Bed rest
• Bblockers
• ACEi
• Anticoag
• ICD
• LVADs
• Transplantation

Question 3

What is arrhythmogenic cardiomyopathy?

Answer 3

Heart muscle disorder which usually affects RV and causes arrhythmias
Heart muscle gets thinned and replaced by fatty-fibrous tissue

Question 4

What is NAXOS disease?

What cardiac effects do we see?

Answer 4

Homozygous inherited syndrome from inbreeding family members which is characterised by peculiar woolly hair and palmoplantar keratoderma as well as arrhythmogenic right ventricular cardiomyopathy (ARVC)

Cardiac effects we see are that of ARVC - fibrous fatty replacement in the RV and changes in ECG showing RBBB and epsilon waves and VT.

Question 5

What is brugada syndrome?
What characteristic changes do we see on an ECG?

How do we prevent sudden cardiac death in these patients?

What do we do to test relatives of those who have died due to sudden cardiac death?

Answer 5

Predominantly an autosomal-dominant condition causing faulty sodium channels and therefore, predisposing to arrhythmias (VT fib), particularly in young males (triggered by something like a fever).

ECG

• Characteristic T wave elevation changes in V1-3.
• RBBB

Prevention of arrhythmias and SCD = Implant a defibrillator

For relatives
- IV ajmaline test (sodium channel blocker which stresses the system) to reveal any masked arrhythmias

Question 6

What is catecholaminergic polymorphic VT?

What are the complications of CPVT?

Answer 6

CPVT is a rare inherited heart rhythm disturbance found in young people and children which causes increased levels of calcium inside cardiac cells.
It is characterised by episodic syncope occuring during exercise or acute emotion in those without structural cardiac defects.

Complications
- VT, Blackouts, sudden death during times. of sudden stress or exercise

Question 7

What is Marfan’s syndrome?
What are the major criteria for diagnosis?
Treatment for Marfans?

Answer 7

Marfans syndrome is an autosomal dominant disorder which affects the connective tissue in the body - (fibrilin-1 abnormality)
25% have no family history

Major criteria for diagnosis (>2 = diagnosis)

• Lense dislocation
• Aortic dissection or dilatation
• Dural ectasia (ballooning or widening of the dural sac which can result in posterior vertebral scalloping)
• Skeletal features - long fingers, armspan > height, pectus deformity, scoliosis (sideways curve of spine), pes planus (flat footed)

Treatment

• Danger is aortic dissection so we treat with b-blockers which reduce the dilatation of aortic root
• Annual echos
• Surgical repair when aortic root >5cm

Question 8

What is familial hypercholesterolaemia?

What are the consequences of FH?

Answer 8

Familial hypercholesterolaemia is an inherited condition which can lead to extremely high cholesterol levels due to LDL receptor abnormalities affecting the way LDL cholesterol is taken out of the circulation and metabolised in the liver

This leads to cholesterol build up in circulation

• CAD and narrowing in coronary arteries
• Tendons anthomata - on back of hands
• Corneal archus where cholesterol build up in the eye.

Treatment (not in lecture)

• high intensity statin and aim for 50% reduction in LDL-C from baseline measurement
• Ezetimibe recommended where either statin therapy is CI, or co-administered with statin if statin is not adequately controlling LDL-C levels below 50% of. baseline level.