Background - Direct myocardial revascularization (DMR) has been examined as an alternative treatment for patients with chronic refractory myocardial ischemic syndromes who are not candidates for conventional coronary revascularization. Methods and Results - We used left ventricular electromagnetic guidance in 77 patients with chronic refractory angina (56 men, mean age 61±11 years, ejection fraction 0.48±0.11) to perform percutaneous DMR with an Ho:YAG laser at 2 J/pulse. Procedural success (laser channels placed in prespecified target zones) was achieved in 76 of 77 patients with an average of 26±10 channels (range 11 to 50 channels). The rate of major in-hospital cardiac adverse events was 2.6%, with no deaths or emergency operations, 1 patient with postprocedural pericardiocentesis, and 1 patient with minor embolic stroke. The rate of out-of-hospital adverse cardiac events (up to 6 months) was 2.6%, with 1 patient with myocardial infarction and 1 patient with stroke. Exercise duration after DMR increased from 387±179 to 454±166 seconds at 1 month and to 479±161 seconds at 6 months (P=0.0001). The time to onset of angina increased from 293±167 to 377±176 seconds at 1 month and to 414±169 seconds at 6 months (P=0.0001). Importantly, the time to ST-segment depression (≥ 1 mm) also increased from 327±178 to 400±172 seconds at 1 month and to 436±175 seconds at 6 months (P=0.001). Angina (Canadian Cardiovascular Society classification) improved from 3.3±0.5 to 2.0±1.2 at 6 months (P<0.001). Nuclear perfusion imaging studies with a dual-isotope technique, however, showed no significant improvements at 1 or 6 months. Conclusions - Percutaneous DMR guided by left ventricular mapping is feasible and safe and reveals improved angina and prolonged exercise duration for up to a 6-month follow-up.