A method of puncturing an interatrial septum between a right atrium and a left atrium may include introducing a distal end of a catheter endoluminally into the right atrium. The method also may include introducing a distal end of a cannula into the right atrium. The cannula may include a proximal first segment and a distal second segment. The distal second segment may be deflectable away from a linear configuration relative to the proximal first segment. A needle tip may be provided at a distal end of the distal second segment. At least a portion of the cannula may be received within a lumen of the catheter. The method also may include deflecting the distal second segment in the right atrium to a deflected configuration by actuating a mechanism at a proximal end of the cannula to align the needle tip with a target point on the interatrial septum.