Before hemodynamic monitoring, carefully select and test the appropriate equipment and calibrate all monitors. To insert the catheter, use strict aseptic technique and, whenever possible, fluoroscopic guidance. The internal jugular vein is generally preferred for cannulation, but cutdown of an antecubital vein may be better for patients receiving anticoagulants or thrombolytics. The balloon remains deflated until the catheter tip is in the right atrium. Characteristic pressure wave forms signal the catheter's passage through each heart chamber. In most patients, advancement from the right atrium to wedge position is completed within 20 to 30 seconds.