Nonreentrant Supraventricular Tachycardia Due to Fast/Slow Pathway Conduction

From Ask Dr Wiki

EKG

Characteristics

1. Tachycardia is due to simultaneous fast and slow pathway conduction resulting in a doubling of the ventricular sinus rate during sinus rhythm.
2. Extremely rare
3. Resistant to multiple medications
4. Patients do not have inducible AVNRT
5. Retrograde VA conduction is poor to absent
6. Must consider triggered junctional bigeminy from a site in the vicinity of the AV Node

Electrophysiological Requirements for Tachycardia

1. There must be absent retrograde conduction over the slow AV nodal pathway
2. ERP of the Fast pathway must be relatively short, at least shorter than that of the slow pathway