Key result
Ultrahigh density mapping revealed that cycle length alternans in atrial tachycardia results from intermittent conduction block or slowing, and catheter ablation successfully terminated all 7 cases.
Why the study?
Atrial tachycardia with cycle length alternans is rare, and its characteristics and precise mechanisms remained to be identified.
Observational (n=7)
Yes
Ultrahigh density mapping reveals that macroreentrant atrial tachycardia with cycle length alternans is driven by intermittent conduction block or slowing, which can be successfully targeted and terminated by catheter ablation.
Answers are grounded in this paper and cite their sources.
Small cohort supports ultrahigh-density mapping for rare AT with CL alternans; leaves open impact on ablation strategies.
BACKGROUND: Atrial tachycardia (AT) with cycle length (CL) alternans is a rare phenomenon. We aimed to identify the characteristics and precise mechanism of this special category of ATs by using an ultrahigh density mapping system. METHODS: We identified 7 ATs with alternating CL in a total of 478 ATs from 2 institutions mapped with an ultrahigh density mapping system. Activation maps were performed for long CL (289±35 ms; mapping points, 21 520±11 103) and short CL (251±18 ms; mapping points,17 594±8059) separately. RESULTS: We classified ATs with CL alternans into 2 types. Type 1: There existed 2 potential loops with different routes. CL alternans resulted from an intermittently 2:1 conducting block within the channel of the smaller loop. Type 2: CL alternans resulted from different conduction velocity through 2 closely spaced gaps within preexisting linear lesions. Catheter ablation successfully terminated all the 7 ATs. CONCLUSIONS: Ultrahigh density mapping provides an opportunity to delineate the precise mechanism of AT with CL alternans. Intermittent conduction block or slowing of a channel was essential for the maintenance of AT.
No takes yet. Share an insight, caveat, or question.
Zhang et al. (2019) conducted an observational in Atrial tachycardia with cycle length alternans (n=7). Ultrahigh density mapping system was evaluated on Mechanism of AT with CL alternans. Ultrahigh density mapping revealed that cycle length alternans in atrial tachycardia results from intermittent conduction block or slowing, and catheter ablation successfully terminated all 7 cases.
Synapse has enriched 5 closely related papers on similar clinical questions. Consider them for comparative context: