PSVT vs AFib: ECG and Symptoms Difference

PSVT or Paroxysmal Supraventricular Tachycardia is a Narrow complex Ventricular Tachycardia that occurs abruptly when normal electrical impulses of the heart are disrupted.

We have provided short notes on PSVT vs Afib for your exam preparation for the Cardiology subject below (especially for Plab part 1). Any queries are welcome in the comments section below.

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ECG of Paroxysmal SupraVentricular Tachycardia

  • The ECG will demonstrate an absolutely regular RR interval with a Heart rate of around 150-250
  • It will also show Narrow QRS- <0.12 seconds QRS (on ECg, 3 small squares = 0.04×3)
  • Also, there will be QRS followed by a T wave (Absent P waves)

PSVT vs Afib Difference in ECG

It is easy yet crucial to differentiate PSVT from Atrial Fibrillation from ECG as both have absent P waves. You can easily distinguish as PSVT will have a regular R-R interval while AF will have an irregular R-R interval.

PSVT vs Torsades De Pointes on ECG

While Management of SVT involves Carotid massage and Valsalva Maneuver followed by IV Adenosine, IV Magnesium Sulphate is given for Torsades de pointes, also known as Polymorphic Ventricular Tachycardia

Management of PSVT

Management of PSVT is initially done by Valsalva maneuver and carotid massage. However, Adenosine is employed readily if the patient deteriorates or the condition does not improve.

Initial Line

  • The initial step involves the Valsalva maneuver and giving Carotid Massage

Not improved?

If the patient does not improve with the above steps, we give Adenosine bolus for management.

  • Intravenous Adenosine (6mg Rapid IV Bolus)
  • Still not improved?- give additional 12mg of Adenosine
  • Still not improved?- give another 12mg of Adenosine
  • Still not improved?- Electrical DC “cardioversion”


  • Adenosine is contraindicated in Asthmatics as it can cause Bronchospasm
  • Verapamil (CCB) is the preferred option in SVT in patients with Asthma

Prevention of future episodes

Beta-blockers remain the mainstay for prophylaxis in patients with PSVT.

  • Beta-blockers such as Propranolol or Radio-frequency ablation

Management of PSVT Short Notes

The management of PSVT is relatively easy to understand. However, one must always remember when not to give Adenosine.

  • First step
    • Carotid massage and Valsalva maneuver
  • 2nd step
    • IV Adenosine 6mg
    • Another IV Adenosine 12mg
    • Another IV Adenosine 18mg
  • 3rd step
    • Verapamil or beta-blocker
  • 4th step
    • Cardioversion (DC Shock) (First step if hemodynamically unstable)
  • ECG- Narrow QRS (<0.12 seconds) f/b T wave and no P wave with Regular R-R interval
  • Prophylaxis- Beta-blocker or Radio-frequency ablation
  • CCB (Verapamil) instead of Adenosine in Asthmatics


Check out the video below if you are looking for detailed aspects of the topic:


Patients of Paroxysmal Supraventricular Tachycardia usually present with racing heart and their heart rates are spiking. Once Adenosine is administered, the heart rate returns to normal within seconds.

It may occur again after a while, and the process is repeated. Management is crucial and it is super important to differentiate it from Atrial Fibrillation as both have different management.

We hope these short notes help you out with exams. You can ask us your queries or leave feedback in the comments section below.


Please note that the information provided in this article is for educational purposes alone. We do not hold any responsibility for its usage in the clinical or practical fields.

This guide has been exclusively made for students preparing for PLAB 1 and shall be used for the same purpose alone. If any information is incorrect or not updated, please mail us or drop them in the comments.

We will readily update any information on PSVT vs Afib if found.

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