A retrograde delivery catheter includes at its distal end an expandable member configured to at least partially occlude the coronary sinus of a patient's heart, and has a length and variable stiffness that allows the distal end to be selectively articulated so as to be positioned in the coronary sinus. The delivery catheter has a triple lumen construction with a primary lumen extending between the proximal and distal ends and configured to allow a cardioplegic fluid to be delivered to the coronary sinus. A second lumen provides for balloon inflation while a third lumen allows monitoring of a pressure within the coronary sinus. A torque may be applied and a reinforcement member within the delivery catheter provides improved torque transmission along the length of the catheter.
