Atypical Fast-Slow Atrioventricular Nodal Reentrant Tachycardia Incorporating a "Superior" Slow Pathway: A Distinct Supraventricular Tachyarrhythmia
Background—The existence of an atypical fast-slow (F/S) atrioventricular (AV) nodal reentrant tachycardia (NRT) including a "superior" (sup) pathway with slow conductive properties and an atrial exit near the His bundle (HB) has not been confirmed.
Methods and Results—We studied 6 women and 2 men (74 ± 7 years of age) with sup-F/S-AVNRT who underwent successful radiofrequency ablation near the HB. Programmed ventricular stimulation induced retrograde conduction over a sup-SP with an earliest atrial activation near the HB, a mean shortest spike-atrial interval of 378 ± 119 ms and decremental properties in all patients. sup-F/S-AVNRT was characterized by 1) a long RP interval, 2) a retrograde atrial activation sequence during tachycardia identical to that over a sup-SP during ventricular pacing, 3) ventriculoatrial dissociation during ventricular overdrive pacing of the tachycardia in 5 patients, or AV block occurring during tachycardia in 3 patients, excluding AV reentrant tachycardia, 4) termination of the tachycardia by adenosine triphosphate and 5) a V-A-V activation sequence immediately after ventricular induction or entrainment of the tachycardia, including dual atrial responses in 2 patients. Elimination or modification of retrograde conduction over the sup-SP by ablation 1) near the right perinodal region, or 2) from the non-coronary cusp of Valsalva, eliminated and confirmed the diagnosis of AVNRT in 4 patients each.
Conclusions—sup-F/S-AVNRT is a distinct supraventricular tachycardia, incorporating a SP located above Koch's triangle as the retrograde limb, which can be eliminated by radiofrequency ablation.
- atrioventricular nodal reentrant tachycardia
- superior slow pathway
- supraventricular tachycardia ablation
- arrhythmia (heart rhythm disorders)
- atrioventricular node
- electrophysiology test
- Received August 3, 2015.
- Revision received October 22, 2015.
- Accepted October 29, 2015.