A method of performing a medical procedure on a patient comprises conveying control signals from a remote controller to a drive unit, intravenously introducing the catheter into a heart of the patient (e.g., via the vena cava into the right atrium), and creating a puncture within a wall between two chambers (e.g., the left and right atria) of the heart. The method further comprises creating a puncture within a wall between two chambers of the heart, and operating the drive unit in accordance with the control signals to advance a working catheter within the guide catheter through the puncture.