Limitations
Confounders may exist in any non-blinded retrospective data set.
However, the use of similar durations of time before and after adoption
at sites that did not add new operators, with a large effect size seen
across three distinct hospital sites, suggests that the influence of
unmeasured confounders may be limited. Although retrospective, these
data reflect the objective endpoint of actual procedure volumes. In the
months prior to this analysis, regulations surrounding
COVID-1923,24 impacted procedural volumes and
caseloads across a variety of surgical specialties; however, procedure
volumes at the study sites had generally returned to normal by the
beginning of the study, consistent with trends seen at the national
level.25,26 We did not acquire demographic or
comorbidity data for this analysis; however, it is unlikely that there
were significant demographic differences between each group. Study sites
remained consistent through the analysis period, no major demographic
transformations occurred at the sites, and in general, a trend of
increasing age and comorbidity burden among patients undergoing AF
ablation exists, which would be expected to bias against the
post-adoption cohort.27,28
Operator experience can affect procedural efficiency, but physicians in
this analysis were generally experienced or even senior operators with
several years out of practice completed. As such, marginal gains in
efficiency over time are likely to be minimal and of limited
contribution to the findings reported.