Arrythmias

Question 1

what investigations would you carry out for an arrhythmia?

Answer 1

> 12 lead ECG, 24 hours
blood tests (thyroid function)
echocardiogram

Question 2

what are the signs and symptoms for supraventricular tachycardia?

Answer 2

> palpitations
dyspnoea
dizziness

Question 3

explain why supraventricular tachycardia occurs with reference to an accessary pathway?

Answer 3

the accessory pathway conducts into the ventricles quicker than the AV node resulting in premature excitation.

Question 4

what may be done to fix intermittent palpitations caused by supraventricular tachycardia?

Answer 4

Valsalva manoeuvre

Question 5

what is the presentation of ventricular tachycardia?

Answer 5

> palpitations
dyspnoea
dizziness
syncope

Question 6

what investigations are carried out for ventricular tachycardia?

Answer 6

> bloods
ECHO
angiogram

Question 7

what are the indications for intermediate cardiovascular defibrillator therapy?

Answer 7

> cardiac arrest due to ventricular failure/tachycardia
sustained ventricular tachycardia causing syncope/significant compromise
sustained ventricular tachycardia with poor left ventricle function

Question 8

what are the intermediate indications for temporary pacing?

Answer 8

> intermediate/sustained symptomatic bradycardia, particularly syncope
prophylactic when a patient is at high risk of development of sever bradycardia (2nd/3rd degree AV block, post anterior MI, or when asymptomatic)

Question 9

what are the indications for permanent pacing?

Answer 9

> symptomatic/profound 2nd/3rd degree AV block
probably mobitz type 2 2nd/3rd degree AV block even if asymptomatic
AV block associated with neuromuscular diseases
after or in preparation for AV node ablation
alternating RBBB/LBBB
syncope when bifascicular/trifascicular block with no other explanation
sinus node disease associated with symptoms
carotid sinus hypersensitivity/malignant vasovagal syncope

Question 10

name three types of arrhythmia

Answer 10

> sinus arrhythmia
supraventricular arrhythmia
ventricular arrhythmia

Question 11

what is an arrhythmia?

Answer 11

any deviation from the normal rhythm of the heart

Question 12

describe how an ecg would look in ventricular fibrillation

Answer 12

rhythm: extremely irregular

p wave: absent

Question 13

is the inside of a cardiac cell more negative or positive compared to the outside?

Answer 13

negative

Question 14

what are the electrophysiological properties of class 1A drugs?

Answer 14

they are fast sodium-channel blockades that delay the repolarisation and increases the action potential duration.

Question 15

what are the electrophysiological properties of class 1b drugs?

Answer 15

they are intermediate sodium-channel blockades that accelerate repolarisation and decrease the action potential duration.

Question 16

what are the electrophysiological properties of class 1c drugs?

Answer 16

they are slow sodium channel blockades that have little effect on the duration of the action potential.

Question 17

what are the electrophysiological properties of class 2 drugs?

Answer 17

beta-adrenergic receptor antagonists (beta-blockers), that reduce the sympathetic nervous system stimulation and depress stage four pf depolarisation.

Question 18

what are the electrophysiological properties of class 3 drugs?

Answer 18

they prolong refractoriness and increase the action potential duration by blocking the potassium channels.

Question 19

what are the electrophysiological properties of class 4 drugs?

Answer 19

they are calcium channel blockades

Question 20

name 3 class 1a drugs

Answer 20

> quinidine
procainamide
dispyramide

Question 21

name 3 class 1b drugs

Answer 21

> lidocaine
mexiletine
tocainide

Question 22

name 2 class 1c drugs

Answer 22

> flecainide

> propafenone

Question 23

name 2 class 2 drugs

Answer 23

> atenolol

> bisoprolol

Question 24

name 3 class 3 drugs

Answer 24

> amiodarone
bretylum
sotalol

Question 25

name 2 class 4 drugs

Answer 25

> diltiazem | > verapamil

Question 26

what are class 1a drugs used for?

Answer 26

> atrial fibrillation > premature atrial contractions > premature ventricular contractions > ventricular tachycardia

Question 27

what are class 1b drugs used for?

Answer 27

> ventricular dysrhthymias

Question 28

what are class 1c drugs used for?

Answer 28

> severe ventricular dysrhythmias | > atrial fibrillation

Question 29

what are class 2 drugs used for?

Answer 29

> supra ventricular and ventricular dysrhythmias | > atrial fibrillation

Question 30

what are class three drugs used for?

Answer 30

> difficult dysrhythmias > life threatening ventricular tachycardia > life threatening atrial fibrillation > sustained ventricular tachycardia

Question 31

what are class four drugs used for?

Answer 31

> paroxysmal supraventricular tachycardia | > rate control of atrial fibrillation

Question 32

what should you not give a patient who is on class four drugs?

Answer 32

beta blockers as they will go into cardiogenic shock and die

Question 33

name two anti-dysrhythmic drugs which are not placed in to one particular category

Answer 33

> digoxin | > adenosine

Question 34

what are the actions of digoxin?

Answer 34

> inhibition of the sodium potassium ATPase pump > positive inotrope (improving contraction strength) > allows more calcium to be available to contraction

Question 35

what is digoxin used for?

Answer 35

> heart failure | > atrial dysrhythmias

Question 36

what are the signs of digoxin toxicity?

Answer 36

``` > vomiting > xanthopsia (yellow glow) > reverse t waves > bradycardia > tachycrdia ```

Question 37

what is the treatment for digoxin toxicity?

Answer 37

> stop digoxin | > if levels are high give digibind which binds to digoxin forming a complex that is excreted in the urine

Question 38

what is amiodarone used to treat?

Answer 38

> ventricular tachycardia | > supraventricular tachycardia

Question 39

what are the potential side effects of amiodarone?

Answer 39

> thyroid (hypo and hyper) > pulmonary fibrosis > corneal deposits > LFT abnormalities

Question 40

what are the effects pf adenosine?

Answer 40

> slowing of conduction through the AV node | > converts paroxysmal supraventricular tachycardia to sinus rhythm

Question 41

how is adenosine administered?

Answer 41

as a fast IV push

Question 42

what can all anti-arrhythmias cause?

Answer 42

arrhythmias

Question 43

what are the indications for anti-coagulation?

Answer 43

``` > atrial fibrillation > valvular heart disease > venous thrombo-embolism > after surgery > immobalisation ```

Question 44

describe arterial thrombosis

Answer 44

adherence of platelets to arterial walls, this is white in colour and is associated with MI, stroke and ischaemia

Question 45

describe venous thrombosis

Answer 45

this develops in areas of stagnated blood flow and is red in colour. it is associated with congestive heart failure, cancer and surgery.

Question 46

what does warfarin inhibit?

Answer 46

the production of active clotting factors

Question 47

what does the direct affect of warfarin depend on?

Answer 47

> concentration of warfarin in the liver > rate of accumulation of warfarin > long t1/2 of clotting factors means slow onset of action

Question 48

what are the adverse effects of warfarin?

Answer 48

> bleeding | > teratogenic

Question 49

explain the CHADS2 score for warfarin

Answer 49

``` C: congestive heart failure H: hypertension A: age more than 75 D: diabetes S: stroke ```