Cardiac Arrhythmias Flashcards Preview

Year 3 - CR > Cardiac Arrhythmias > Flashcards

Flashcards in Cardiac Arrhythmias Deck (65)
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1

what should you look for in your general approach to arrhythymias

- whether the heart rhythm is fast (tachycardia) or slow (bradycardia)
- you should see whether the patient is presenting acutely or electively
- you should see whether the arrhythmia is primary (the heart) or secondary (something else)

2

what is tachycardia

greater than 100bpm

3

What is bradycardia

less than 60bpm

4

How do you assess the patient with tachycardia and what do you do in unstable tachycardia

- Monitor SpO2 and give oxygen if they are hypoxic
- monitor ECG and BP and record 12 lead ECG
- obtain IV access
- identify and treat reversible causes

adverse features
- shock
- MI
- heart failure
- Syncope

- if you have these adverse features then this means that the tachycardia is unstable
- if the tachycardia is unstable you should administer a synchronised DC shock up to 3 times

5

What are the adverse features of tachycardia

- shock
- MI
- heart failure
- Syncope

6

What do you do in stable tachycardia

- Look to see if the QRS is narrow (at less than 0.12s)
-

7

What do you do in unstable tachycardia

adverse features
- shock
- MI
- heart failure
- Syncope

- if you have these adverse features then this means that the tachycardia is unstable
- if the tachycardia is unstable you should administer a synchronised DC shock up to 3 times

8

What determines the width of the QRS complex

using normal confusion system (his-purkinje system) to active ventricles
- tachycardia where ventricles are activated by a normal conduction system

9

Name how a narrow QRS complex is caused and define it

- ECG shows a rate of greater than 100bpm and a QRS complex duration of less than 120ms

- it is caused supra-ventricular tachycardia and this is due to a complication happening above the bundle of his and above the ventricles, occur when the ventricles are depolarised via normal conduction pathways

10

What is another name for a narrow QRS complex

Supra-ventricular tachycardia

11

Name the types of supra-ventricular tachycardia

• Atrial fibrillation/flutter/tachycardia

• Atrio-Ventricular Nodal Reentrant Tachycardia

• Atrio-Ventricular Reentrant Tachycardia

12

Why are Atrial fibrillation/flutter/tachycardia
grouped together as a type of ventricular tachycardia

- substrate from the arrhythmia originates from the atria themselves

13

What causes atrial flutter

- Counter clockwise circuit going through the right atria

14

What does Atrial flutter look like on the ECG wave

- Saw tooth P flutter waves - negative in the inferior leads
- 150bpm is the ventricular rate

15

what causes atrial fibrillation

- random depolarisation in different parts of the atrial fibrillation

16

What does the ECG look like of atrial fibrillation

- RR intervals are irregular
- lack of P waves

17

Describe the treatment for atrial fibrillation in stages

- Acute rate and rhythm control
- manage precipitating factors - lifestyle changes, treatment of underlying cardiovascular conditions
- assess stroke risk - oral anticoagulation in patients at risk for stroke
- rate control therapy
- antiarrhtymic drugs, cardioversion, catheter ablation, AF, surgery

18

Describe how you would decide what medication you would use for AF

if LVEF is greater than or equal to 40%
- beta blocker or dilitiazem or verapamil
- if this does not wokr add digoxin
- initial resting heart rate target is less than 110bpm

If LVEF is less than 40% or if there are sings of congestive heart failure
- smallest dose of beta blocker to achieve rate control
- add digoxin
- initial resting heart rate target is less than 110bpm

For both of these
- avoid bradycardia
- perform echocardiogram to determine further management/choice of maintenance therapy
- consider need for anticoagulation

19

Describe how the CHADVASC score works in assessing stroke risk in atrial firbillation

- Congestive heart failure = 1
- Hypertension = 1
- Age 65-74 =1, over 75 = 2
- Diabetes = 1
- Stroke or prior TIA = 2
- Vascular disease = 1
- S – female sex = 1
If the score is 0 = then no treatment
If the score is 1 = males: consider anticoagulation, females no treatment
If score is 2 or more than offer anticoagulation

20

What is used to work out the risk of stroke occurring in atrial fibrillation

(CHADSVASC score)

21

How do you treat atrial fibrillation

Rate control
- either with a beta blocker or a rate limiting calcium channel blocker (e.g. dilimiazem)

Rhythm control
- either cardio version or drug induced cardioversion with amodiarone

22

What causes atrial ventricular node re-entry tachyarrthymia

- this is a re-entrant circuit that develops around the AV node
- re entry within the AV node
- fast and regular

23

What happens in atrio-ventricular reentrant tachycardia

- this occurs in patients with pre-excitation
- accessory pathway that allows electrical activity in the ventricle which occurs with the normal electrical pathway

24

What does an ECG look like in atrio-ventricular reentrant tachycardia

- Delta wave

25

What is another word for atrio-ventricular reentrant tachycardia

Wolff-Parkinson white syndrome
- pre-excited ECG
- documented tachycardia/palpitation symptoms

- orthodromic AVRT
- - the ventricle is activated down the pukinje his pathway and then goes up the accessory pathway

26

What happens in the orthodromic AVRT

- the ventricle is activated down the pukinje his pathway and then goes up the accessory pathway
- Narrow QRS complex

27

What happens in the antidromic AVRT

the ventricles are activated by the accessory pathway therefore the right side of the ventricle is activated first, the pathway then goes back up the bundle of His
- Broad QRS complex

28

What happens when there is atrial fibrillation in the top chambers and conducts down

- atrial fibrillation in the top chambers and is conducting down into the ventricles via the AV node and the accessory pathway
- fast
- broad
- irregular
- emergency - DC cardioversion and then need inpatient ablation

29

What happens when you ablate the accessory pathway

Delta waves disappear

30

What can you use to treat atrial ventricular node re-entry tachyarrthymia and atrio-ventricular reentrant tachycardia

- both of these tachycardia depend on the node
- therefore any vagal termination with vagal manoeuvre and adenosine can terminate the tachycardia