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SVT Case Study

Jul 9, 2020 | 0 comments

This patient is a 53-year-old female with a history of palpitations. 

Baseline Recording

What rhythm is observed in the following electrogram? 

1.  AVNRT

2.  Atrial Tachycardia

3.  Sinus Rhythm

4.  Junctional

Answer

Sinus Rhythm

 
The activation sequence is high to low and right to left such as in sinus rhythm. There is a P wave before each narrow QRS complex and a clear A, H, and V on the His catheter. Measurements are not displayed, but appear to be within the normal range. 
 

Initial Testing

What is observed in the following electrogram? 

1.  AVNERP

2.  AERP

3.  VAERP

4.  VERP

 

Answer

AERP

This is atrial extrastimulus testing. The last two impulses of the drive train are displayed as well as the extrastimulus. On the S2 there is a pacing artifact with no atrial depolarization to follow – AERP. 

Tachycardia

What is the most likely rhythm observed in the following electrogram? 

1.  AVNRT

2.  AVRT

3.  Atrial Tachycardia

4.  Atrial Flutter

 

Answer

Atrial Tachycardia

 
The most likely rhythm is atrial tachycardia; however, additional testing should be performed. The tachycardia cycle length is 450 ms.
  

Differential Testing

What is observed in the following ventricular overdrive pacing maneuver? 

1.  No Entrainment

2.  VAV

3.  VAHV

4.  VAAV

 

Answer

VAAV

 
A VAAV response is associated with atrial tachycardia.  
 

Activation Mapping

When should activation mapping of this rhythm be performed? 

1.  During sinus rhythm

2.  During tachycardia

3.  During atrial pacing

4.  During ventricular pacing

Answer

During Tachycardia

 
The target for ablation is the earliest atrial activation pre P wave such as seen in this example with the A on the ablation channel 42 ms ahead of the P wave. Atrial tachycardia was successfully ablation at this location with an RF ablation catheter.
  

3D Activation Mapping

Two rhythms were mapped during this procedure, sinus and atrial tachycardia. Which rhythm is observed in map A? 

1.  Sinus Rhythm

2. Atrial Tachycardia

 

 

Answer

Sinus Rhythm

 
In map A. the earliest activation is seen in the area of the sinus node. Early activation is seen in white, followed by red, orange, yellow, green, blue, and purple. With other mapping systems, the earliest activation is red and then followed by the same pattern.
 

More Information: 

For more information on any aspect of this case study or component of an electrophysiology study, please see:  EP Essentials – Understanding EP: A Comprehensive Approach. 

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