Method of reducing left atrial pressure

A medical implant delivery system for accessing a coronary sinus, the system comprising:

• a first delivery catheter, at least a distal portion of the first delivery catheter being sized to advance into a right atrium, through a coronary sinus ostium, and into the coronary sinus from the right atrium, the distal portion of the first delivery catheter comprising a side outlet opening;
• a second delivery catheter, at least a distal portion of the second delivery catheter being sized to advance out of the first delivery catheter through the side outlet opening, the distal portion of the second delivery catheter having a puncture component associated with a distal end of the second delivery catheter, the puncture component being sized to form an opening extending from a left atrium into the coronary sinus to provide a blood flow pathway and relieve elevated left atrial pressure;
• and
• an expandable medical device sized for delivery within the second delivery catheter and for placement within the opening.

A system for forming an opening between a coronary sinus and a left atrium, the system comprising:

• a first delivery catheter comprising a side outlet opening at a distal portion of the first delivery catheter and being rotatable to orient the side outlet opening toward the left atrium, the first delivery catheter sized to advance from a right atrium of a heart into the coronary sinus and sized for placement within the coronary sinus;
• an expandable anchor coupled to the first delivery catheter, the expandable anchor being sized to expand to contact an inner surface of the coronary sinus for stabilizing the first delivery catheter within the coronary sinus;
• a second delivery catheter pre-loaded within the first delivery catheter, a distal portion of the second delivery catheter sized to advance outwardly through the side outlet opening toward a target wall portion of the coronary sinus following delivery into the coronary sinus;
• and
• a puncture component associated with a distal end of the second delivery catheter, the puncture component having a shape to puncture the target wall portion to form the opening between the coronary sinus and the left atrium.