Adam B. Greenbaum et al. JACEP 2015;1:434-441 Subxiphoid Access After the transatrial pericardial microcatheter is placed, the subxiphoid needle is positioned outside of the heart (A). In the lateral fluoroscopic projection, the pericardium is filled with 1.0 to 1.5 ml/kg of CO2 to displace the heart posteriorly (B). The gas clearly visualizes the anterior wall of the heart to allow needle entry without cardiac contact. (C) The subxiphoid guidewire is then advanced through the needle, and the procedure continues as usual. Adam B. Greenbaum et al. JACEP 2015;1:434-441 American College of Cardiology Foundation