Arrythmias Flashcards
(44 cards)
What is an arrhythmia?
An abnormality in the rate and/or rhythm of the heart
Name the groups of arrhythmia?
- Cardiac arrest rhythms
- Narrow complex tachy rhythms (AF, A flutter, SVT)
- Broad complex tachy rhythms (VT, SVT with bundle branch block)
Name the cardiac arrest rhythms and whether or not they’re shockable.
Shockable
- VT
- VF
Not Shockable
- PEA
- Asystole
How is a tachycardic rhythm treated if the Pt is unstable?
- Up to 3 synchronised shocks
- Consider amiodarone infusion
How is a stable patient treated with tachycardic rhythm?
- AF- Beta-blocker (or diltiazem CCB)
- Flutter- Beta-blocker
- SVT- Vagal manoeuvre e.g. valsalva and adenosine
- VT- amiodarone infusion
- SVT bundle branch block- vagal manoeuvre and adenosine
What causes atrial flutter?
Re-entrant rhythm
- self-perpetuating loop due to an extra pathway
What is the atrial and ventricular rate in a flutter?
Atrial = 300BPM
Ventricular = 150BPM
What does an ECG show in flutter?
- Saw tooth appearance (P wave followed by P wave)
Which conditions are associated with flutter?
- HTN
- Ischaemic heart disease
- Cardiomyopathy
- Thyrotoxicosis
How is flutter treated?
- Rate control (beta-blocker) or cardioversion
- Radiofrequency ablation of the re-entrant rhythm
- Anticoag (CHA2DS2VASc)
What is an SVT?
- Electrical signal re-enters the atria from the ventricle
- Travels back through the AV node into the ventricle again, causing a second contraction from the same impulse
- Self-perpetuating loop (AVN-Vent-AVN-Vent…)
What does an ECG show in SVT?
- QRS, T wave, QRS, T wave…
What are the three types of SVT?
- Atrioventricular nodal re-entrant tachy (impulse goes back through the AVN)
- Atrioventricular re-entry tachy (accessory pathway e.g. Wolff-Parkinson-White)
- Atrial tachy (ectopics)
How are SVTs acutely managed in a stable patient?
- Continuous ECG
- Valsalva manoeuvre
- Carotid sinus massage
- Adenosine or Verapamil
- DC cardioversion if all else fails
How does adenosine work?
Slows conduction at the AVN, resetting sinus rhythm, causes brief asystole/bradycardia before it is quickly metabolised
When is adenosine CI?
- Asthma
- COPD
- HF
- Severe hypotension
What dosing of adenosine is used IV?
6mg, then 12mg, then 12mg if no improvement
What is the long-term treatment of SVT?
Medication
- Beta-blocker/CCB/amiodarone
Radiofrequency ablation
What is the cause of Wolff-Parkinson-White?
Accessory pathway- the Bundle of Kent
How is WPW treated definitively?
Radiofrequency ablation of the Bundle of Kent
What ECG changes are seen in WPW?
- Short PR (<0.12s)
- Delta wave (rising up into QRS)
- Wide QRS (0.12s+)
What is Radiofrequency Ablation?
1- Catheter in the femoral vein, fed on a wire through to the heart under XR guidance
2- In the heart, it is placed against different parts to test for electrical signals
3- Once an accessory is found, the ablation (heat) is applied to burn the area, and the scar tissue cannot conduct
What is Torsades de Pointes?
Polymorphic VT- ‘twisting of the tips’
- QRSs get smaller and smaller, then big and smaller and smaller…
- Seen in long QT
What causes Torsades de Pointes?
Long QT- prolonged repolarisation
- High risk of early afterdepolarisation