Inherited Cardiac Conditions

Question 1

What are the 3 types of inherited cardiac conditions?

Answer 1

Cardiomyopathies, channelopathies and aortopathy.

Question 2

What are the 2 types of arrhythmic inherited cardiac conditions?

Answer 2

Channelopathies and cardiomyopathies.

Question 3

Give examples of channelopathies.

Answer 3

Congential long QT syndrome, Brudaga syndrome, short QT syndrome, progressive familial conduction disease, familial AF, familial WPW (Wolf Parkinson White).

Question 4

Give examples of cardiomyopathies that cause arrhythmias.

Answer 4

Hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy (ARVC), dilated cardiomyopathy.

Question 5

What causes channelopathies?

Answer 5

Mutations in genes that encode the cardiac ion channels.

Question 6

What part of the cardiac cycle do channelopathies usually affect?

Answer 6

Repolarisation.

Question 7

What can cause AF in a young person?

Answer 7

Channelopathies.

Question 8

What channels are most commonly mutated in long QT syndrome?

Answer 8

Potassium channels.

Question 9

How long does the QT interval have to be to be considered congenital long QT syndrome?

Answer 9

> 440ms in males, >450ms in females.

Question 10

Give some examples of autosomal dominant causes of long QT syndrome.

Answer 10

Isolated LQT: Romano-Ward syndrome.

Extra cardiac features: Anderson-Tawil syndrome, Timothy syndrome.

Question 11

Give examples of autosomal recessive causes of long QT and what are they associated with?

Answer 11

Jervell and Lange-Nielsen syndrome. Deafness.

Question 12

What is the hallmark arrhythmia of congenital long QT syndrome?

Answer 12

Polymorphic VT (Torsades de Pointes VT).

Question 13

What are other arrhythmias associated with long QT?

Answer 13

Lone AF, heart block.

Question 14

What are the usualy primary presenting complaints in long QT?

Answer 14

Syncope, sudden cardiac death (SCD) in children and young adults.

Question 15

Why is the QT interval prolonged?

Answer 15

There is less repolarising current which prolongs the AP (due to decreased potassium and increased sodium currents).

Question 16

What is the management of long QT syndrome?

Answer 16

Avoid QT prolonging drugs (no included in BNF, look on www.crediblemed.org.
Correction of electrolyte abnormalities.
Avoidance of triggers: strenuous swimming, breath holding, loud sudden noises.

Question 17

What are the arrhythmias associated with Brudaga syndrome?

Answer 17

Risk of polymorphic VT/VF. AF common.

Question 18

What are the ECG changes associated with brudaga syndrome and are they constant?

Answer 18

ST elevation and RBBB in V1-V3. Changes may be intermittent and change over time. May only be seen with provocative testing with flecainide or ajmaline (drugs that block cardiac sodium channel).

Question 19

How many genes are associated with Brudaga syndrome and what channels do they affect?

Answer 19

Cardiac sodium and calcium channels.

Question 20

What are the triggers of VF in Brudaga syndrome?

Answer 20

Rest or sleep, fever, excessive alcohol or large meals.

Question 21

What does not influence the prognosis in Brudaga syndrome?

Answer 21

Genotype and family history of SCD.

Question 22

How can triggers of Brudaga syndrome be avoided?

Answer 22

Avoidance of certain drugs, avoidance of excessive alcohol intake and large meals, genotype and family history of SCD does not influence prognosis.

Question 23

When would ICD implantation be considered and recommended in a patient with Brudaga syndrome?

Answer 23

Considered: spontaneous diagnostic type I ECG pattern and history of syncope.
Recommended: Survivors of aborted cardiac arrest or have documented spontaneous sustained VT.

Question 24

What drugs would you avoid prescribing in long QT syndrome?

Answer 24

Anti-arrhythmic drugs, psychotropics, analgesics, anaesthetics. Look on brugadadrugs.org.

Question 25

What is the clinical presentation of hypertrophic obstructive cardiomyopathy (HOCM)?

Answer 25

Sudden death, heart failure, angina, AF, asymptomatic.

Question 26

If dilated cardiomyopathy is X-linked, the mutation will be in the gene for which protein?

Answer 26

Dystrophin.

Question 27

Why is it important to diagnose inherited cardiac conditions before symptoms appear?

Answer 27

SCD may be the only presentation, young age group at risk, effective therapies are available. There will likely be no co-morbidities so many years of benefit from therapeutic strategies.

Question 28

What does diagnosis of inherited cardiac conditions require a combo of?

Answer 28

Clinical and genetic testing.

Question 29

Should people exercise if they have an inherited cardiac condition and why?

Answer 29

Yes, as it prevents health problems and improves psychological well-being.

Question 30

What should the next step be after spontaneous cardiac death?

Answer 30

Assessing relatives for disease and risk to prevent further deaths.

Question 31

Describe how cascade screening works.

Answer 31

Once a diagnosis is confirmed in an individual, testing is extended to first degree and second degree relatives and so on.