Abstract: Disclosed are a system, device, and method for controlling a differential fluid pressure between chambers in a heart. The device includes an implantable pop-off valve that may be secured between two chambers of a heart, such as the left and right atriums. The pop-off valve is normally in a closed position. If a differential fluid pressure across the device exceeds a pre-determined value, the pop-off valve is arranged to open to enable blood flow between the two chambers of the heart. When it is determined that the differential fluid pressure is substantially below the pre-determined value, the pop-off valve is configured to close. The system and method further discloses means for implanting the device into a septal region of the heart.