Transmyocardial revascularization, called TMR, uses a laser to open new channels for blood flow to the heart muscle, and was originally developed for people who could not undergo coronary artery bypass surgery or who would not or did not benefit from catheter-based angioplasty.

The surgery is performed through an incision on the left side of the chest, where an opening between two ribs is created to view and work on the heart. The laser is activated to make tiny openings into the heart muscle. When the new opening is confirmed by images from transesophageal echocardiography, the physician uses gentle pressure to close the outer opening of the channel on the myocardium, while leaving the interior channel open into the inside of the heart, or endocardium. As blood flows through the affected heart chamber, the new channel provides blood flow to previously under-nourished tissues. The procedure involves the creation of multiple channels into the affected area and, potentially, stimulates creation of new blood vessels to serve the revascularized tissues.