Not only randomized controlled trials, but also case series should be considered in systematic reviews of rapidly developing technologies

In the case of RFCA for AF, the case series make a useful contribution to the systematic review. Inclusion of case series can increase the evidence base and strengthen the credibility of a review of an emerging health technology. These advantages must be balanced against the risk of bias associated with the lack of a control group, potential publication bias, overrepresentation of results from specialist centers, and overlap of patients across series. Specification in the review protocol of inclusion criteria for outcomes and quality criteria is recommended to make optimum use of case series.