Arrythmia

Question 1

what is arrhythmia

Answer 1

problem with heart rate

Question 2

what is bradycardia

Answer 2

slowed heart rate

Question 3

what is tachycardia

Answer 3

increased heart rate

Question 4

how can we classify arrhythmia

Answer 4

Location of damage

Effect on rate

Question 5

describe the structure of the heart

Answer 5

Structure of the heart

• left and right atria
• left and right ventricle

Atria and ventricles split by bicuspid and tricuspid valves

Seperated via septum

Question 6

describe the conduction of a heart beat

Answer 6

Sino atrial node conducts an action potential down to the atrio ventricular node

where there is a sleight delay 0.1s to allow the atria to contract.

This then goes down the bundle of his into the atrioventricular bundle branches down into the perkinje fibers causing the ventricle to contract in unison.

Question 7

What are the 5 phases of a cardiac action potential

Answer 7

0 rapid depolarization

1 initial repolarization

2 plateux

3 repolarization

4 baseline

Question 8

What does Na+ influx lead to

Answer 8

rapid depolarization (phase 0)

Question 9

what does Ca2+ influx lead to

Answer 9

slow depolarization (phase 2)

Question 10

what does K+ efflux lead to

Answer 10

repolarization and hyperpolarization (phase 3)

Question 11

what is refractory period of the heart

Answer 11

time take to evoke another Ap constriction limiting absolute contract rate

Question 12

what is refractory period dependent on

Answer 12

Na+ channels

Question 13

describe how action potentials in pacemaker cells work

Answer 13

action potential threshold higher than in muscles -65 needed

slower upstroke of AP gives slower conduction due to L type voltage dependent calcium channels

resting membrane potential is unstable called the pacemaker potential

Question 14

what is the rhythm of the heart controlled by

Answer 14

autonomic nervous system (ANS)

Question 15

describe how the ANS acts on the heart to controll heart rate

Answer 15

right vagus has acetyl choling acting on M2 receptors

symptathetic noradrenaline acts on beta 1 adrenoceptors

left vagus has acetyl choline acting on m2 receptors

Question 16

describe the different parts of an electrocardiogram

Answer 16

P wave = atrial depolarization

QRS complex = ventricular muscle depolarization

T wave = ventricular repolarization during intraventricular conduction time

PR interval = conduction from atrium to ventricle

QT interval = duration of ventricular action potential

Question 17

what is heart block

Answer 17

damage to the conducting system of heart in total heart block, atria and ventricles beat indepndently the rate is determined by the pacemaker that is distal to the condition block.

Question 18

how do we treat total heartblock

Answer 18

pacemaker devices

Question 19

what is ectopic pacemaker activity

Answer 19

pacemaker activity from areas other than SAN

Question 20

what are the causes of ectopic pacemaker activity

Answer 20

sympathetic activity can promote ectopic activity

ischaemia partial depolarization

delayed after depolarization

Question 21

what is re entry - arrythmias

Answer 21

normally action potential dies out in ventricles as surrounding tissue is still in refractory period

damage can mean APs re-excite areas that refractory period has ended, termed re entry or circus movement

ischaemic damage a common cause can cause arterial and ventricular tachycardia and fibrillation

Question 22

Describe the cardiac action potential

Answer 22

-96 as Na+ moves in depolarization occurs

+52 K+ and Cl- out

Ca2+ in K+ out

K+ out repolarization

Question 23

what is vaugn williams classification based on

Answer 23

electrophysiological properties of drugs

Question 24

what are the 4 classes of vaugn williams

Answer 24

sodium channel blockers

beta blockers

amiodarone like drugs

calcium channel blockers

Question 25

what do sodium channel blockers do

Answer 25

block voltage gated sodium channels phase 0 of the cardiac action potential

Question 26

what are the 3 classes of sodium channel blockers

Answer 26

Class la - intermediate kinetics Class lb - Fast kinetics block open channel during phase 0 reducing max depolarization before next beat Class Ic - Slow kinetics steady state of block during whole cardiac cycle

Question 27

what is the role of beta blockers

Answer 27

block action of adrenlaine/noradrenaline on heart to prevent tachyarrhytmias

Question 28

how do beta blockers work

Answer 28

Supress actions of sympathetic nervous system, reducing depolarization in phase 4 of the pacemaker AP

Question 29

what is the overall effect of a beta blocker

Answer 29

Slowing heart rate and force of contraction

Question 30

what are the main side effects of a beta blocker

Answer 30

hypertension and ischaemic heart disease

Question 31

what was amiordarone like originally based on

Answer 31

action of amiordarone however not includes other such as sotalol

Question 32

what does amiordarone like do

Answer 32

prolong the cardiac ap increasing the refractory period inhibiting potassium channels involved in phase 3

Question 33

what are the serious potential adverse effects of amiordarone

Answer 33

lead to pro arrhythmic effects such by prolonging Q-T interval

Question 34

what do calcium channel blocker do

Answer 34

they slow the conduction in the sino atrial and atrio ventricular node where action potential depends on calcium entry which reduces the duration of the plateu of the action potential

Question 35

what effect does the calcium channel blocker have

Answer 35

reduces for of heart beat also reduce after depolarization preventing ectopic beat

Question 36

what do class 1 drugs work on

Answer 36

phase - 0

Question 37

what do class 2 drugs work on

Answer 37

phase 2 and 4

Question 38

what do class 3 drugs work on

Answer 38

phase 3

Question 39

what drug are not classified in vaugn williams system

Answer 39

many however one of which is anti arrhytmic drugs

Question 40

what is adenosine used in

Answer 40

supraventriculartachycardia (SVT), stops SVT if other measures fail as action are short lived it is safer than verapamil

Question 41

what does digoxin do

Answer 41

used in Atrial fibrillation as slows AV conduction by blocking Na/K atpase involved in resetting the pacemaker cell ion balances

Question 42

what non pharmacological treatment options exist for arrhythmias

Answer 42

DC cardioversion - electronic paddles which deliver shocks performed under anaesthetic used for SVT and VT if haemodynamically unstable implantable defibrillator catheter ablation high power radio waves used to lesion small areas known to be causing tachyarrhythmias electronic pacemaker

Question 43

what 4 things do we consider when managing arrhythmia

Answer 43

eliminate cause make diagnosis determine baseline condition therapy needed?

Question 44

what are the two types of tachyarrhythmias

Answer 44

supraventricular SVT ventricular VT

Question 45

what are some symptoms of SVT

Answer 45

palpitations, fainting/light headedness and shortness of breath; sometimes causes peripheral and even pulmonary oedema

Question 46

what is the most common sustained arrhythmia

Answer 46

supraventricular artial fibrillation

Question 47

what are the causes of supraventricular atrial fibrillation

Answer 47

``` hypertension valvular heart disease coronary disease heart failure hyperthyroidism pulmonary embolism lungcancer ```

Question 48

what is the difference between a normal ecg and one with Atrial fibrilation

Answer 48

lack of P wave

Question 49

what are the 3 types of atrial fibrillation

Answer 49

paroxysmal afib persistent afib permanent afib

Question 50

Describe the nice guideline for atrial fibrillation

Answer 50

Confirm diagnosis do further investigations including risk stratifcation for stroke thromboembolism if paroxysmal af carry out rythm control if failure carry out rate control if permanent carry out rate control and if remains symptomatic carry out rythm control if persistant determine whether rhythm or rate then treat appropriatly

Question 51

what can we use for rate control

Answer 51

beta blocker or calcium antagonist sedentary patients use digoxin

Question 52

what can we use for rhythm control

Answer 52

electrical cardioversion pharmacological cardioversion - Class I catheter ablation

Question 53

if atrial fibrilation what is assessed

Answer 53

CHA2DS2Vasc

Question 54

if CHA2DS2VASc score is greater than 2 in a patient with atrial fibrilation what is recommmended

Answer 54

anticoagulant

Question 55

what is HAS-BLED used for

Answer 55

determine bleeding risk for use of anticoagulants in AF

Question 56

if hasbled score is greater than 3 what risk is it

Answer 56

high risk of bleeding and thus requires additional monitoring

Question 57

what is supraventricular AVNRT / AVRT termed

Answer 57

paroxysmal supraventricular tachycadria

Question 58

what does AVNRT stand for

Answer 58

atrioventricular nodal re entranct tachycardia

Question 59

what does AVRT

Answer 59

atrioventricular re entranct tachycardia

Question 60

what can be used to treat supraventricular AVNRT / AVRT

Answer 60

often terminated by non pharmacological means e.g. carotid massage or reflex vagal stim however can be terminated by adenosine as well

Question 61

what are some causings of ventricular tachyarrhytmias

Answer 61

congenital heart disease drugs that prolong long QT interval changes in blood pH, ionic balance etc Ischaemic heart disease

Question 62

how do we treat VT and Vf

Answer 62

cardioversion to restore sinus rhythm sustained VT can be treated with amiodarone class 1c or 1b non sustained VT can be treated with a beta blocker or sotalol implantable cardioversion, catheter ablation