Systems and methods are provided for navigating within the heart and attaching to the wall of the heart for performing injection of one or more agents into tissue. The system includes an outer catheter, a mid catheter slidably disposed within a lumen of the outer catheter, and a needle catheter slidably disposed within a lumen of the mid catheter. The mid catheter includes a vacuum hood attached to a mid catheter distal end such that a radiopaque distal tip of the mid catheter extends into the vacuum hood. The vacuum hood includes at least two radiopaque features, the spatial relationship of which visibly changes under fluoroscopy when the vacuum hood is under sealed vacuum.