Transseptal puncture (TSP) may not be possible in cases of an elastic, aneurysmal, or thickened interatrial septum (IAS). During deep inspiration (DI), the chest wall expands and the diaphragm descends. This makes intrapleural pressure to become more negative, which leads to movement of the IAS to the right side. The aim of this study was to verify prospectively the feasibility, safety, and outcome of DI associated with conventional TSP technique in patients with challenging IAS anatomy. From September 2012 to May 2016, 224 patients underwent TSP due to different indications. Patients were divided into 2 groups: 213 patients in whom the left atrium was successfully accessed in 3 attempts were grouped as conventional TSP group and 11 patients in whom left atrium access was failed after 3 conventional attempts were grouped as DI-TSP group.

Conventional TSP was successful in 89.6% of patients with the first attempt. Second and third attempts were required in 4.1% and 1.4%, respectively. Septal puncture was achieved at the first attempt in 10 patients within a median of 1 second of DI maneuver (interquartile range, 1 to 3) and without any complications. Challenging IAS anatomy consisting of IAS aneurysm, a thick IAS, and an excessively mobile IAS were more frequent in the DI-TSP group (45% to 8%, 27% to 3%, and 21% to 5%, respectively, p <0.001). In conclusion, TSP by using the DI maneuver may be a reliable and safe method after failed conventional attempts. If there is any doubt about the correct location of the needle, additional imaging modalities have to be used.