Future directions for research
For VISITAG™ RF annotation-guided procedures, another important determinant of auto-annotation logic towards a suitable definition for stable catheter-tissue interaction is the choice of position stability filter setting. Indeed, a possible solution to the inaccuracy of the RMA “on” setting as described here, is to use a smaller position stability filter range – e.g. 1.5mm. Although a complete description of the effects of this position filter setting is beyond the scope of this present report, data supplement figure 19 demonstrates left PV annotated site-1 data for case #5 (reconstituted data curves in figure 2), using the RMA “off” with 2mm position stability, and RMA “on” with 1.5mm position stability range. Importantly, when using 1.5mm range with RMA “on”, annotated RF duration at site-1 is 1.6s greater, yet as shown in figure 2, position stability and CF changes indicating catheter displacement coincide with annotation using RMA “off” and 2mm range (blue vertical line). In this case, further evidence towards this earlier time point representing the true site of catheter displacement is provided by the UE morphology change from pure R (site-1 end) to RS (site-2 onset) coinciding with RMA “off” and 2mm range annotation timing. Clearly, such a delay to recognition of true catheter motion of 1.6s is likely to be clinically important, particularly when considering HPSD ablation.
Together with a steerable sheath for catheter support, high frequency jet ventilation (HFJV) has been shown to reduce the occurrence of acute and chronic pulmonary vein reconnections and improve freedom from AF.15 Theoretically, complete absence of respiratory motion not only eliminates the requirement for respiratory adjustment, but also confers the advantage of eliminating any operator and/or patient-specific requirement for adjustments to sheath and/or catheter position according to the respiratory cycle. Accordingly, RF annotation-guided PVI protocols using HFJV may demonstrate greater reproducibility and efficacy.