A device for perfusing a coronary sinus of a subject's heart which may include: a double-lumen catheter including: a first lumen having: a proximal opening, and a distal opening configured to be positioned in a coronary sinus of a subject's heart; and a second lumen parallel to the first lumen, the second lumen having: a proximal opening, and a distal opening being offset from the distal opening of the first lumen towards the proximal opening of the second lumen in a longitudinal direction, the distal opening of the second lumen being configured to be positioned in a right atrium of the subject's heart; and an oxygenator connected to the proximal openings of the first lumen and the second lumen, the oxygenator is configured to oxygenate deoxygenated blood.