Supraventricular Tachycardia Flashcards
What is the definition of supra-ventricular tachycardia?
regular, narrow-complex tachycardia (>100bpm) with no p waves, & supraventricular origin
What are the types of supraventricular tachycardia?
- Atrioventricular Nodal
- Re-entry Tachycardia (AVNRT)
- Atrioventricular Re-entry Tachycardia (AVRT)
- WPW
What are the signs and symptoms of supraventricular tachycardia?
- Palpitations
- Chest Pain
- Syncope / dizziness
- SOB
What is AVNRT?
Functional re-entry circuit so Impulse propagates with a ‘functional’ conduction block
What is AVRT?
- Anatomical re-entry circuit
- ‘Bundle of Kent’
- WPW is a subtype
What investigations are done for supraventricular tachycardia?
- ECG
- U&Es
- TFTs
- Digoxin level
- Cardiac enzymes
What are different types of AVNRT?
- Slow-fast (most common)
- Fast-slow
- slow-slow
What are ECG changes in AVRT?
- Retrograde (flipped) P waves (after QRS)
- Tachycardia
- Narrow QRS
What is the management of SVT?
- Valsalva manoruvre
2. 6mg adenosine, then 12mg in 1-2mins if no effect x2
What do you do if the SVT is still present?
verapamil
What do you do if SVT still present after verapamil/pt unstable?
DC cardioversion
What is the long term SVT management?
catheter ablation
What is the ecg changes on slow-fast AVNRT?
- P waves are often hidden – being embedded in the QRS complexes.
- Pseudo R’ wave may be seen in V1 or V2.
- Pseudo S waves may be seen in leads II, III or aVF.
- In most cases this results in a ‘typical’ SVT appearance with absent P waves and tachycardia
What are ecg changes in fast-slow AVNRT?
- QRS-P-T complexes.
2. Retrograde P waves are visible between the QRS and T wave.
What are ecg changes in slow-slow AVNRT?
- Tachycardia with a P-wave seen in mid-diastole, effectively appearing “before” the QRS complex.
- May be misinterpreted as sinus tachycardia
