Arrythmias

Question 1

How long is the PR interval in sinus rhythm?

Answer 1

0.12->0.2s

Question 2

How long is the QRS complex?

Answer 2

0.08s
abnormal considered >0.12s

Question 3

How long is the QT interval?

Answer 3

Varies with HR but at 60BPM ~0.42 seconds

Question 4

What is sinus bradycardia/Sinus tachycardia and how are they treated?

Answer 4

Normal rhythm but slow or fast (<60BPM or >80BPM) in a healthy adult
Sinus Bradycardia:
B1 receptor agonist - Isoprenaline - Short Term
Pacemaker - Long Term

Sinus Tachycardia: Internal Defribillator

Question 5

What is Sinus Arrest?

Answer 5

A pause in the heart beat with no waves at all
Usually misses atleast 2 beaths
Underlying rythm is usually slow and irregular sinus rythm

Question 6

What is an escape beat?

Answer 6

The first beat after a sinus arrest, its triggered by a abckup pacemaker so is slightly out of sync but then the SA takes over agian

Question 7

What is (Broad Complex Tachy) Ventricular Tachycardia and what causes it?

Answer 7

A very high but regular Heart Rate
Ventricular cells are irritated or scarred causing them to fire independantly of the normal conduction and rapidly

Question 8

How does ventricular tachycardia (broad Complex Tachy) present, ECG and whats the danger?

Answer 8

Palpitations - Syncope - Lightheadedness - sOB - Angina
ECG: Hr >120BPM - Broad QRS complex - often 3 wide QRS between P waves
- Can devolve into Vfib

Question 9

What is Vfib?

Answer 9

Ventricles quivering instead of contracting

Question 10

HOw does vfib manifest clinically and on ECG?

Answer 10

Cardiac arrest - syncope - no pulse - no breathing - angina - cyanosis - naeusea
Irregular unformed QRS and no p waves

Question 11

What are the indications for ICD?

Answer 11

Secondary Prevention:
- Cardiac arrest due to VF/VT
- Sustained VT -> syncope or significant compromise
- Sustained VT with poor LV function

Question 12

What is supraventricular tachycardia?

Answer 12

Tachycardia starting at or above the AV node
Present with palpitaions - anxiety - chest pain - dizziness - SOB
Supraventricular ectopic beats - Afib - Aflutter - W-P-W

Question 13

What is Wolff-Parkinson-White syndrome?

Answer 13

A type of supraventricular tachycardia of the AV re-entrant type:
A short P-R interval with a slow rising R wave.
Due to:
An extra accessory pathway bypassing the AV node straight to the ventricles, thus signal travels faster thugh the accessory pathway so the ventricle is triggered faster (short P-R) and for a longer time (slow rising R wave).
Can slip into a re-entry circuit causing tachycardia

Question 14

What is Atrial Flutter?

Answer 14

A supraventricular Tachycardia caused by one of the backup pacemakers going wrong and firing way above the SA node at 250-300BPM, because the AV node has a delay the ventricles will contract closer to 150BPM.

Question 15

How does Atrial Flutter appear on an ECG?

Answer 15

Saw tooth P wave going v fast.
V high QRS rate but regular

Question 16

What is Afib?

Answer 16

A type of supraventricular tachycardia. Abnormal electrical activity in atria leads to random atria spasming & random irregularly irregular AV node stimulation

Question 17

HOw does afib appear on an ECG?

Answer 17

NO distinct p waves
Irregularly Irregular QRS complexes (rapid)

Question 18

What other tests can be done for Afib?

Answer 18

Bloods - Esp TFTs
Echo - Quivering Atria
Pulse - Rapid and irregularly iregular

Question 19

How does Afib present?

Answer 19

Fatigue
Palpitations
SOB
Angina
Oedema
Emboli -> Stroke

Question 20

How do we treat Afib?

Answer 20

Rate Control:
Class 2, 4 and 5 anti-arrthmics - B blockers (atenolol), RL CCBs and Digoxin

Rhythm Control:
Electrical Cadioversion
Chemical Cadioversion (Class 1c Flecainide {Na blocker} and 3 Amiodarone {Prolongs refractory})

Anti-Coagulants:
Aspirin + clopidogrel and warfarin to prevent emboli

Question 21

What is 1st degree heart block?

Answer 21

A P-R interval over 0.2 seconds (5 small squeres)

Question 22

What could you see on an ECG in severe type 1 Heart block?

Answer 22

P wave buried in previous T wave

Question 23

Describe the 2 types of 2nd degree AV block, the problem and the treatment?

Answer 23

Mobitz 1:
- Progressive P-R prolongation culminating in a non-conducted P wave (skipped QRS)
- Malfunctioning AV node
- Treat with Atropine

Mobitz 2:
- Intermittant non-conducted P waves with no prolongations
- Worse than Mobitz 1
- Problem below AV node
- Treat with a pacemaker

Question 24

What is a fixed ratio block?

Answer 24

Shown in type 2 AV block
blocks of a fixed ratio of P-QRS waves

Question 25

Describe 3rd degree heart block?

Answer 25

Complete AV block
Both P waves and QRS are reuglar but unrelated
May include ventricular standstill
Usually develops at the end point of 2nd degree

Treat with Atropine and Pacemaker

Question 26

What is Polymorphic Ventricular Tachycardia?

Answer 26

Ventricular Tachycardia where multiple ventricular foci causing the QRS complexes to be varied in amplitude, axis and duration
The commonest Cause is Myocardial Ischaemia

Question 27

What is Torsades De Pointes?

Answer 27

A specific type of Polymorphic Ventricular Tachycardia in the context of QT prolongation.

Question 28

How does torsades de pointes appear on an ECG?

Answer 28

PVT and QT prolongation appearing like massive QRS complexes twisting around the central line.
Like the Arctic monkeys album cover

Question 29

How does Torsades de Pointes present and whats it treated with?

Answer 29

Usually its short lived and self-limiting but it can devolve into Vfib
It presents haemodynamic instability and collapse.