Pulmonary vein encirclement using an Ablation Index-guided point-by-point workflow: cardiovascular magnetic resonance assessment of left atrial scar formation

Abstract

Aims A point-by-point workflow for pulmonary vein isolation (PVI) targeting pre-defined Ablation Index values (a composite of contact force, time, and power) and minimizing interlesion distance may optimize the creation of contiguous ablation lesions whilst minimizing scar formation. We aimed to compare ablation scar formation in patients undergoing PVI using this workflow to patients undergoing a continuous catheter drag workflow. Methods and results Post-ablation cardiovascular magnetic resonance imaging was performed in patients undergoing 1st-time PVI using a parameter-guided point-by-point workflow (n = 26). Total left atrial scar burden and the width and continuity of the pulmonary vein encirclement were determined on analysis of atrial late gadolinium enhancement sequences. Comparison was made with a cohort of patients (n = 20) undergoing PVI using continuous drag lesions. Mean post-ablation scar burden and scar width were significantly lower in the point-by-point group than in the control group (6.6 ± 6.8% vs. 9.6 ± 5.0%, P = 0.03 and 7.9 ± 3.6 mm vs. 10.7 ± 2.3 mm, P = 0.003). More complete bilateral pulmonary vein encirclements were seen in the point-by-point group (P = 0.038). All patients achieved acute PVI. Conclusion Pulmonary vein isolation using a point-by-point workflow is feasible and results in a lower scar burden and scar width with more complete pulmonary vein encirclements than a conventional drag lesion approach.

OpenEP: A Cross-Platform Electroanatomic Mapping Data Format and Analysis Platform for Electrophysiology Research

“…These points are labeled as such in userdata.electric.tags and have location data stored in userdata.electric.egmX and .egmSurfX but have no linked electrical data. Modern electroanatomic mapping systems provide metrics which quantify energy delivery (and seek to predict lesion size) during radiofrequency ablation, such as the Lesion Size Index (Whitaker et al, 2018) and Ablation Index (O'Neill et al, 2019). Since these indices vary per-platform and per-case, OpenEP provides helper functions for accessing radiofrequency index data which is appended to userdata and then stored in the subfields of userdata.rfindex.…”

Software Framework to Quantify Pulmonary Vein Isolation Atrium Scar Tissue

“…To generate the scar map, the Scar Quantification pipeline of CemrgApp was used as described in previous studies [7], [8]. The pipeline consists of a semi-automatic segmentation of the MRA scan.…”

“…ii) Assessing ablation lesions. Following a procedure similar to the one shown in [8], an encircling corridor around the veins is generated via user-defined points. The points are joined by the Dijkstra algorithm, calculating the shortest path weighted by the signal intensity values.…”

Intentions and consequences: Power applied and current delivered during radiofrequency ablation

“…The Ablation Index is a weighted formula incorporating power, contact force, and time. 4 Similarly, the competing Lesion Size Index is a weighted formula incorporating contact force, time and current. 5 Notably, in Bourier et al's 3…”

“…Indeed, ablation parameters have been incorporated into the clinically available lesion metric indices discussed by the authors. The Ablation Index is a weighted formula incorporating power, contact force, and time 4 . Similarly, the competing Lesion Size Index is a weighted formula incorporating contact force, time and current 5 .…”