Impact of adenosine on mechanisms sustaining persistent atrial fibrillation: Analysis of contact electrograms and non-invasive ECGI mapping data

Abstract

Background: We evaluated the effect of adenosine upon mechanisms sustaining persistent AF through analysis of contact electrograms and ECGI mapping.

Methods: Persistent AF patients undergoing catheter ablation were included. ECGI maps and cycle length (CL) measurements were recorded in the left and right atrial appendages and repeated following boluses of 18 mg of intravenous adenosine. Potential drivers (PDs) were defined as focal or rotational activations completing ≥ 1.5 revolutions. Distribution of PDs was assessed using an 18 segment biatrial model.

Results: 46 patients were enrolled. Mean age was 63.4 ± 9.8 years with 33 (72%) being male. There was no significant difference in the number of PDs recorded at baseline compared to adenosine (42.1 ± 15.2 vs 40.4 ± 13.0; p = 0.417), nor in the number of segments harbouring PDs, (13 (11-14) vs 12 (10-14); p = 0.169). There was a significantly higher percentage of PDs that were focal in the adenosine maps (36.2 ± 15.2 vs 32.2 ± 14.4; p < 0.001). There was a significant shortening of CL in the adenosine maps compared to baseline which was more marked in the right atrium than left atrium (176.7 ± 34.7 vs 149.9 ± 27.7 ms; p < 0.001 and 165.6 ± 31.7 vs 148.3 ± 28.4 ms; p = 0.003).

Conclusion: Adenosine led to a small but significant shortening of CL which was more marked in the right than left atrium and may relate to shortening of refractory periods rather than an increase in driver burden or distribution. Registered on Clinicaltrials.gov: NCT03394404.

Conflict of interest statement

Ross Hunter has received research grants from Medtronic, educational grants from Biosense Webster, and speaker fees from Medtronic and Biosense Webster. Pier Lambiase receives research grants from Medtronic, Abbott and Boston Scientific. This work is supported by UCLH Biomedicine NIHR and Barts BRC. Ross Hunter, Richard Schilling, and Shohreh Honarbakhsh were inventors of the STAR mapping system and are shareholders in Rhythm AI Ltd. This does not alter our adherence to PLOS ONE policies on sharing data and materials.” (as detailed online in our guide for authors https://journals.plos.org/plosone/s/competing-interests).

Figures

Fig 1. Flowchart of phenotype AF: Adenosine sub study.

Flowchart describing how patients enrolled into the Phenotype AF study were recruited to this sub study.

Fig 2. Image from the ECGI system showing a focal activation being reviewed.

Screenshot from the ECGI workstation software. This screen allows the operator to select any potential focal or rotational driver and for review. Far left: LAO view of the composite biatrial map displaying focal PDs (orange hexagons) and yellow/orange areas as a heat map with darker colour showing greater number of rotational PDs occurrences. A selected focal PD is highlighted in green. Right image: a phase map with the activation sequence for that focal PD with the blue region showing the site of earliest activation, spreading out through light blue, green, then yellow and red colours. The raw unipolar electrogram is displayed on the bottom right panel. The software can display the unipolar electrograms from any point on the phase map.

Fig 3. Cycle length measurements at baseline and with adenosine.

Cycle length measurements from the same patient at baseline and with Adenosine. The surface ECG leads are shown at the top (blue channels) with a quadripolar catheter in the right atrial appendage (green channels) and the Achieve mapping catheter in the left atrial appendage (yellow channels). Cycle length recordings taken in this patient at the RAA are shorter in the Adenosine maps compared to baseline but are similar in both at the LAA.

Fig 4. ECGI composites maps at baseline and with adenosine.

ECGI Composite maps from the same patient at baseline and with Adenosine. In this figure the orange hexagons represent focal drivers and the yellow/orange areas are regions where rotational drivers have been detected. The numbers in the diagram represent the number of revolutions completed for each rotational PD occurrence in that region. the overall burden and distribution of PDs is very similar, but the proportion of PDs that are focal is arguable slightly increased in the maps following administration of adenosine.