Series 2

Non-Sustained SVT

Author: Xavier Richmond

A 41 y/o female, presented to the Emergency Department in a symptomatic tachycardia, with a heart rate alternating between 140-150bpm. The documented tachycardia was identified as a “short RP tachycardia”, with vaguely identifiable P-waves. Before any type of cardioversion could be administered, the patient’s arrhythmia spontaneously self-terminated. 

Weeks later, the patient was brought into the catheterization lab for an elective electrophysiology study, with a possible ablation, if warranted. The patient would receive general anesthesia, if a transseptal puncture would be required.  

The physician inserted four diagnostic catheters into the patient’s heart via four femoral access sites. Three of the four diagnostic catheters were placed in the right atrium, while one diagnostic catheter was placed into the right ventricle. For this EP study, three Inquiry Steerable quads (6Fr, 2-5-2mm in the HRA, HIS & RV) and one Inquiry Steerable deca (6Fr, 2-5-2mm – in CS) were used for stimulation & recording. 

Upon initiation of the EP study, right ventricular pacing identified the lack of retrograde conduction through the patient’s AV node. 

What rhythm is essentially eliminated as a diagnosis with this finding? 

  1. Atrial tachycardia
  2. AVNRT
  3. AVRT
  4. Atrial Flutter

With the diagnosis of atrial tachycardia but with only frequent PACs observed, is the physician able to map and treat the arrhythmia? If so, what type of map would be most beneficial?  

  1. Yes, Pace Map
  2. Yes, Reentrant Map
  3. Yes, LAT (activation timing map)
  4. Yes, Substrate (voltage map)
  5. No – this is not able to be mapped since the tachycardia is not sustained