Electrophysiological characteristics and catheter ablation of atypical fast-slow atrioventricular nodal reentrant tachycardia using an inferolateral left atrial slow pathway

Abstract Background Understandings of subtypes atypical atrioventricular nodal reentrant tachycardia (AVNRT) using variants slow pathway (SP) are still growing. Inferolateral (inf-lat-) left atrial (LA) SP is a rare variant extending into an inf-lat-LA along the mitral annulus (MA). Purpose To characterize unknown subtype fast-slow (F/S-) AVNRT inf-lat-LA-SP as retrograde limb (inf-lat-LA-F/S-AVNRT). Methods This Japanese multicenter retrospective study enrolled 4 patients inf-lat-LA-F/S-AVNRT that was characterized by earliest site activation during (EAA) between 3 and 6 o'clock MA. The diagnosis made exclusion AV (AVRT) (AT) according to standard criteria confirmed successful elimination inf-lat-LA-SP. Results Surface ECG revealed long RP appearance except one who had short due conduction time across During tachycardia, far-field LA preceding near-field coronary sinus (CS) musculature visible in CS recording 2. Retrograde via with decremental delay consistently reproducible ventricular stimulation 2, 1 whom double response, while it always masked presence fast block at lower common 1. An injection small dose ATP transiently interrupted over inf-lat-LA-SP, suggesting its ATP-sensitivity. Exclusion AVRT no resetting extrastimulus 2 VA dissociation overdrive pacing remaining AT V-A-V response after entrainment termination without capture Ablation right-sided unsuccessful eliminate but ablation or near EAA transseptal approach cure associated following development accelerated junction rhythm all. Low-frequency potentials local activation, consistent were detected MA medial Conclusions Differential especially should include inf-lat-LA-F/S-AVNRT. Presumed arrhythmogenic substrate seemed be remnant embryogenic ring tissue electropharmacological locational characteristics. Successful this can obtained not SP. Funding Acknowledgement Type funding sources: None.