The cardioprotective efficacy of coronary perfusion during angioplasty was evaluated. Forty-two patients underwent transcatheter infusion of oxygenated Fluosol DA, 20% emulsion (FDA-20), a perfluorocarbon oxygen transport fluid, into the distal coronary artery during balloon inflations. Left ventricular function was continuously monitored by two-dimensional echocardiography, and left ventricular ejection fraction was quantitatively analyzed from the video record by an area-length method with a validated computer algorithm. Each patient had multiple nonperfused and perfused balloon inflations lasting more than 45 seconds. Nineteen of the 42 patients also received control solutions of oxygenated Ringer's lactate and nonoxygenated FDA-20. The ejection fraction of nonperfused sequences fell from a baseline value of 57 +/- 15% to 36 +/- 14% at 45 seconds of inflation time (p less than 0.0005). Falls of similar magnitude were seen in the lactated Ringer's and nonoxygenated FDA-20 perfused balloon inflations. The ejection fraction fall was associated with a 54% rise in end-systolic volume (p less than 0.0005) and a 4% rise in end-diastolic volume (p = ns) compared to baseline. Inflations perfused with oxygenated FDA-20 showed a 45-second, left ventricular ejection fraction of 53 +/- 13% (p = ns compared to baseline), which was significantly greater (p less than 0.0001) than the 45-second ejection fraction of the nonperfused, or control solution perfused sequences. Results indicate that the profound fall in ejection fraction occurring during percutaneous transluminal coronary angioplasty can be ameliorated by distal coronary perfusion with an oxygenated perfluorocarbon emulsion.