Background: The effect of adenosine on electrophysiological phenomena during AF is poorly understood.
Objective: To analyse the impact of adenosine on mechanisms of AF propagation.
Methods: The study included 22 patients undergoing ablation for persistent AF using the AcQMap non-contact mapping system. Recordings of AF propagation were made before and after administration of adenosine at one or more of 3 time points during the procedure: pre-pulmonary vein isolation (PVI), post PVI, or at the end of the case. QRS-T signals were subtracted and data was analysed using custom designed software to quantify localised rotational activation (LRA), localised irregular activation (LIA) and focal firings (FF). Virtual dipoles were exported and phase mapping applied to calculate the global cycle length (AFCL) and identify phase singularities (PS). Low frequency of activation patterns were removed to increase specificity using cut offs resulting in a relative 5, 10, 20 and 30% drop in the time each pattern was present over the recording. Patterns were quantified for the number of occurrences, percentage time present, and the surface area affected.
Results: Analysis included 35 paired 5 second segments. Adenosine shortened global mean AFCL from 182±14 to 165±16 (difference 17ms, 95% CI 11-22, p<0.0005). With no cut off adenosine resulted in an increase in LRA occurrences from 16±8 to 24±10 (8, 4-12; p<0.0005) with a 14% (7-20; p<0.0005) increase in the time LRA was present but only a 7% (3-11; p0.001) increase in surface area affected. These findings were consistent across all cut offs but with minimal effect on LRA surface area (<2%) at higher cut offs with 67% of LRA regions in the same location as LRA at baseline. PS numbers increased from 30±8 to 37±9 (7, 3-10, p<0.002) and duration increased by 90ms (13-167, p=0.023). There was a small increase in LIA occurrences only at lower cut offs and no change in the surface area affected. There was no difference in the frequency of FF. At median follow up of 9 months, 91% were free of AF recurrence.
Conclusion: Adenosine shortens global AFCL and promotes rotational activation, which occurred at a higher frequency and duration but covering a similar atrial surface area. This implies a possible mechanistic role of rotational activation in AF maintenance.