6: Inherited cardiac conditions

Question 1

What are the two main types of inherited heart disease?

Answer 1

Channelopathies (leading to arrythmia)

Cardiomyopathies

Question 2

What is a common sign of inherited heart disease?

Answer 2

Arrythmias

Question 3

People with inherited heart disease often present with what type of arrythmia?

Answer 3

Sinus bradycardia

You may fit a pacemaker and never know that the disease has a genetic basis

Question 4

Name three common channelopathies.

Answer 4

Long QT syndrome

Brugada syndrome

Catecholaminergic polymorphic ventricular tachycardia (CPVT)

Question 5

Name three common cardiomyopathies.

Answer 5

Hypertrophic cardiomyopathy

Arrythmogenic right ventricular cardiomyopathy (ARVC)

Dilated cardiomyopathy

Question 6

Inherited cardiac conditions tend to be diagnosed using which kind of test?

Answer 6

Genetic testing

Question 7

Inherited cardiac condition patients need to be advised on how they can manage their ___ factors.

Answer 7

risk

Question 8

If a patient is diagnosed with inherited cardiac disease, who else may be screened?

Answer 8

The patient’s family

Question 9

How does channelopathy cause arrythmia?

Answer 9

Movement of ions into/out of cardiac cells becomes dysfunctional, depolarisation doesn’t occur properly and therefore contraction of muscle doesn’t either

Question 10

The most common mutation causing channelopathy is that of ___ channels, which causes ___ __ ___.

Answer 10

K⁺ channels

Long QT syndrome

Question 11

Mutations in which channel’s genes causes Brugada syndrome?

Answer 11

Na⁺ channels

Question 12

Mutations in Ryanodine channel genes causes which type of arrythmia?

Answer 12

Cathecolaminergic polymorphic ventricular tachycardia (CPVT)

Question 13

What causes Long QT syndrome?

Answer 13

Mutations in K⁺ channels

Reduction in repolarising currents

Resulting in longer action potentials

Question 14

What arrythmia can occur as a result of QT interval prolongation?

Answer 14

Ventricular tachycardia (to compensate for reduced heart rate)

Question 15

What symptom can occur in people with long QT syndrome?

Answer 15

Syncope

Question 16

What channelopathy do you (probably) have if your QT interval is >= 0.48s?

Answer 16

Long QT syndrome

Question 17

How long must your QT interval be to be diagnosed with long QT syndrome?

Answer 17

>= 0.48s

Question 18

There are ___ variations of long QT syndrome with different ___ of lethal cardiac events.

Answer 18

three

triggers

Question 19

In patients with long QT syndrome - you need to avoid specific ___ - why?

Answer 19

drugs

Some drugs further prolong the QT interval, which puts patients at risk of arrythmia and sudden death

Question 20

Patients with long QT syndrome should avoid ___ which may cause arrythmia.

Answer 20

triggers

Question 21

What is an example of a trigger for LQTS1?

Answer 21

Breath holding → avoid strenuous swimming

Question 22

What is an example of a trigger for LQTS2?

Answer 22

Loud noises (alarm clocks, guns, gaffs)

Question 23

What arrythmia is common in Brugada syndrome?

Answer 23

Atrial fibrillation

Question 24

What channels are affected in Brugada syndrome?

Answer 24

Sodium channels

Calcium channels

(slows upstroke and prolongs action potential)

Question 25

What are some ECG indicators of Brugada syndrome?

Answer 25

**ST elevation in chest leads**

Question 26

Which drugs may you need to give a patient to bring out ECG changes characteristic of Brugada syndrome?

Answer 26

**Sodium channel blockers** e.g Flecainide, ?ajmaline

Question 27

What drug treatments should be avoided in patients with Brugada syndrome?

Answer 27

**Anti-arrhythmic drugs** (e.g Na⁺ channel blockers - flecainide, ajmaline) ## Footnote **Psychotropic drugs** **Analgesics** **Anaesthetics**

Question 28

Which inherited cardiac disease is induced by adrenergics?

Answer 28

**Catecholaminergic polymorphic VENTRICULAR TACHYCARDIA**

Question 29

What is CPVT triggered by?

Answer 29

**Emotional stress** **Physical activity** (anything that releases catecholamines like adrenaline)

Question 30

What kind of VT will be seen in the ECG of someone with CPVT?

Answer 30

**Bi-directional ventricular tachycardia**

Question 31

Why are CPVT patients advised to avoid strenuous exercise and stress?

Answer 31

Releases adrenaline, which is a trigger for the VT

Question 32

Use of ___ - which give out adrenaline-producing, stressful shocks, should be considered carefully in those with CPVT.

Answer 32

**Pacemakers**

Question 33

Which sodium channel blocker improves the outcome of those with CPVT?

Answer 33

**Flecainide** (remember that it's strongly contraindicated in Brugada syndrome)

Question 34

Which class of drugs is used to calm VT in CPVT?

Answer 34

**Beta blockers** (beta adrenoceptor antagonists)

Question 35

Which kind of cardiomyopathy is most common?

Answer 35

**Hypertrophic cardiomyopathy**

Question 36

Name three types of inherited cardiomyopathy.

Answer 36

**Hypertrophic cardiomyopathy** **Dilated cardiomyopathy** and Cardiomyopathy which selectively targets the right ventricle: **Arrhytmogenic right ventricular cardiomyopathy (ARVC)**

Question 37

Hypertrophic cardiomyopathy ___ the myocardium and causes stiffening, reducing the ___ \_\_\_.

Answer 37

**thickens** **cardiac output**

Question 38

What arrythmia can occur as a result of hypertrophic cardiomyopathy?

Answer 38

Blood doesn't pump so back pressure causes **atrial hypertrophy / dilatation** **⇒** atrial fibrillation

Question 39

If a patient's presentation, ECG etc. suggest cardiac hypertrophy but you can't pin down a specific disease, what should be tested?

Answer 39

**Genetics**

Question 40

When should the use of nitrates be avoided?

Answer 40

**Significant outflow tract obstruction** because it reduces coronary filling in patients already prone to ischaemia, syncope

Question 41

What does ICD stand for?

Answer 41

**Implantible cardioverter defibrillator**

Question 42

What is an ICD used for?

Answer 42

**Restores normal sinus rhythm by shocking an arrythmia**

Question 43

What is **dilated cardiomyopathy**?

Answer 43

**Dilatation of the left ventricle, reducing cardiac output** due to poorer pumping capability

Question 44

What is **arrhythmogenic right ventricular cardiomyopathy**?

Answer 44

Fibro-fatty replacement of cardiac myocytes in the **RIGHT VENTRICLE**, which causes arrythmia (e.g VT)

Question 45

Why should patients with **ARVC** avoid competitive sports?

Answer 45

**Associated with increased right ventricle pressure** which worsens the conditions

Question 46

What drugs and mechanical interventions are recommended in patients with ARVC?

Answer 46

**Beta blockers** or amiodarine **ICD implantation** or catheter ablation of affected nerves

Question 47

What may the only presentation be for someone with an undiagnosed, inherited cardiac condition?

Answer 47

**Sudden death** you want to avoid this

Question 48

ICDs have a variety of possible \_\_\_.

Answer 48

**complications**

Question 49

What are some complications associated with ICDs?

Answer 49

**Endocarditis** **Perforation** **Thromboembolic events**

Question 50

What kind of screening involves investigating people more at risk of ICD, e.g family, rather than random individuals?

Answer 50

**Cascade screening**

Question 51

On an ECG, what is **torsades de pointes**? Which type of arrythmia is it? What inherited cardiac condition is it an indicator of? What arrythmia can it degenerate into?

Answer 51

**Irregular QRS complexes which seem to twist around the ECG baseline** Polymorphic VT **Long QT syndrome** Ventricular tachycardia

Question 52

Which arrythmia can be triggered in people with **Brugada syndrome**?

Answer 52

**Ventricular fibrillation**

Question 53

What can trigger ventricular fibrillation in people with Brugada syndrome?

Answer 53

**Rest / sleep**

Question 54

What kind of polymorphic arrythmia is seen in catecholaminergenic polymorphic ventricular tachycardia **(CPVT)**?

Answer 54

**Bi-directional ventricular tachycardia**