Modified Transseptal Puncture Technique in Challenging Septa: A Randomized Comparison to Conventional Technique.

Background. Transseptal puncture (TSP) can be challenging. We compared safety and efficacy of a modified TSP technique ("mosquito" technique, MOSQ-TSP) to conventional TSP (CONV-TSP). Method. Patients undergoing AF ablation in whom first attempt of TSP did not result in left atrial (LA) pressure (failure to cross, FTC) were randomized to MOSQ-TSP (i.e., puncture of the fossa via a wafer-thin inner stylet) or CONV-TSP (i.e., additional punctures at different positions). Primary endpoint was LA access. Secondary endpoints were safety, time, fluoroscopic dose (dose-area product, DAP), and number of additional punctures from FTC to final LA access. Result. Of 384 patients, 68 had FTC (MOSQ-TSP, n = 34 versus CONV-TSP, n = 34). No complications were reported. In MOSQ-TSP, primary endpoint was 100% (versus 73.5%, p < 0.002), median time to LA access was 72 s [from 37 to 384 s] (versus 326 s [from 75 s to 1936 s], p < 0.002), mean DAP to LA access was 1778 ± 2315 mGy/cm(2) (versus 9347 ± 10690 mGy/cm(2), p < 0.002), and median number of additional punctures was 2 [1 to 3] (versus 0, p < 0.002). Conclusion. In AF patients in whom the first attempt of TSP fails, the "mosquito" technique allows effective, safe, and time sparing LA access. This approach might facilitate TSP in elastic, aneurysmatic, or fibrosed septa.