A system for creating a passage through the pericardium of a patient to permit access of a cardiac harness delivery device, including a tubular introducer sleeve and a tubular dilator sleeve insertable into the introducer sleeve. The introducer sleeve has a slot and a distal portion biased in a reduced opening. The distal end being positioned within an incision through the pericardium. Insertion of the dilator sleeve into the introducer sleeve causes it to push outwardly against the reduced opening, thereby expanding the reduced opening of the introducer sleeve sufficiently to permit a cardiac harness delivery device to access the epicardium. The introducer sleeve is releasably locked to the dilator sleeve by operation of a slot on the introducer sleeve and a protrusion on the dilator sleeve, which slides within the slot. The slot has detents that releasably lock the dilator sleeve at alternative positions within the introducer sleeve, thereby maintaining the reduced opening or, alternatively, the expanded opening to facilitate operation of a cardiac harness delivery device.