To date, application of laser angioplasty in acute myocardial infarction (MI) has not been reported. In nine patients with acute myocardial infarction complicated by continuous or recurrent severe ischemia and chest pain, a mid-infrared, solid-state, pulse-wave holmium/thulium:YAG coronary laser was applied. In six of these patients the laser was specifically utilized for the purpose of coronary thrombolysis. In each case a guidewire was placed across the stenosis and a multifiber laser catheter was utilized, emitting 250-600 mJ/pulse at 5 Hz, followed by adjunctive balloon angioplasty. Laser success (defined as ability to cross the lesion, reduction of > or = 20% in stenosis and thrombolysis when a thrombus is present) was achieved in all patients. Final angiograms revealed residual stenosis < or = 30%, adequate thrombolysis and no major complication (MI, perforation, emergency CABGS, CVA, death) in each patient. Clinically, all nine patients improved, survived the acute infarction and were discharged. This initial clinical experience demonstrates the feasibility and safety of holmium/thulium:YAG laser application in thrombolysis and plaque ablation in selected patients who experience acute myocardial infarction complicated by prolonged or recurrent ischemia and chest pain.