When performing TMR a qualified cardiac surgeon delivers a precise laser therapy (either with a Holmium:YAG laser or CO2), directly to the target area(s) of the heart muscle. When performed as a primary therapy, it is done through a small incision between the ribs (thoracotomy) with the patient under general anesthesia. Transmyocardial laser revascularization (TMR) can also be performed as a secondary procedure in patients that have ischemic heart disease with areas of the heart that cannot be bypassed. The precise laser therapy is delivered to create small channels into the heart chamber. During a typical procedure, approximately 10 –50 channels are made in each targeted region of the heart muscle.