AVNRT With Intermittent Aberrancy-Mimicking Ventricular Tachycardia: One Tachycardia, Two QRS Morphologies
Vineet Madishetty1, Badal Sojitra1, Vincent Sachs1
1Internal Medicine/Cardiology, HCA Healthcare/USF Morsani College of Medicine GME/Largo Medical Center, Largo, Florida, USA.
JACC. Case Reports
|July 30, 2026
Summary
Wide-complex tachycardia can mimic ventricular tachycardia, but supraventricular tachycardia with aberrancy is a common cause. Electrophysiology confirmed this in a patient with alternating QRS widths.
Area of Science:
- Cardiology
- Electrophysiology
Background:
- Wide-complex tachycardia (WCT) diagnosis can be challenging.
- Supraventricular tachycardia (SVT) with aberrancy frequently mimics ventricular tachycardia (VT).
Purpose of the Study:
- To illustrate a case of SVT with rate-dependent aberrancy.
- To highlight diagnostic clues for differentiating SVT with aberrancy from VT.
Main Methods:
- Case presentation of a 36-year-old male with recurrent palpitations and dizziness.
- Utilized telemetry, vagal maneuvers, pharmacologic agents (adenosine, diltiazem), and electrophysiology study (EPS).
Main Results:
- Patient presented with tachycardia >200 bpm and alternating narrow/wide QRS.
- Rhythm transiently responded to vagal maneuvers, adenosine, and diltiazem but recurred.
- EPS induced atrioventricular nodal re-entrant tachycardia (AVNRT) with rate-dependent aberrancy; slow-pathway ablation was successful.
Conclusions:
- Unchanged tachycardia cycle length during narrow-to-wide QRS transitions suggests a single SVT mechanism with functional bundle branch block.
- Alternating QRS morphology without cycle length change warrants suspicion for SVT with aberrancy, confirmed by EPS.
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