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.