Apparatus and method for locating coronary sinus

A method for locating a coronary sinus of a patient's heart, the method comprising:

• inserting an intravascular device into a vasculature of a patient, the intravascular device comprising an elongated member having distal and proximal sections and at least one lumen extending therethrough, the intravascular device further comprising at least one optical fiber extending through the lumen, the optical fiber having a distal end configured to contact with a blood flow within the patient's heart and a proximal end coupled to a laser Doppler velocimetry system;
• advancing the intravascular device to a predetermined startup location within the right atrium of patient's heart;
• performing a plurality of laser Doppler velocity measurements of the blood flow within the heart while moving the intravascular device from the predetermined startup location over a plurality of locations within the right atrium of patient's heart;
• and
• determining the laser Doppler velocity measurement having the maximum value from the plurality of laser Doppler velocity measurements.

A guidewire for locating a coronary sinus of a patient's heart, the guidewire comprising:

• an elongated guidewire body having a lumen extending therethrough;
• an atraumatic distal tip formed at a distal end of the distal core section;
• and
• at least one optical fiber longitudinally disposed through the lumen, the optical fiber having a distal end to contact with a blood flow within the patient's heart and a proximal end to couple to a laser Doppler velocimetry system for performing a plurality of laser Doppler velocity measurements of the blood flow within the heart to locate the coronary sinus of the heart.