Does intracoronary infusion of Fluosol-DA 20% prevent left ventricular diastolic dysfunction during coronary balloon angioplasty? Distal intracoronary infusion of the perfluorochemical Fluosol-DA 20% has been shown to prevent systolic dysfunction during coronary artery balloon occlusion in coronary angioplasty. To assess its effect on global diastolic dysfunction, a randomized, single-blind, crossover protocol comparing intracoronary infusion of Fluosol or no infusion (control) was performed during 60 s balloon inflations in 10 patients (mean age 67 years) undergoing coronary angioplasty. Assessment of global systolic and diastolic function was obtained with high fidelity micromanometer measurements of left ventricular pressure. Eighteen pairs of balloon inflations (Fluosol versus control) were analyzed. Patients reported significantly less severe chest pain during inflations accompanied by Fluosol compared with control. However, during coronary balloon occlusion, no significant differences in the changes from baseline values were observed between Fluosol and control with regard to ventricular relaxation, including the time constant of early ventricular relaxation (tau) and maximal rate of fall in left ventricular pressure (maximal negative dP/dt). No differences between Fluosol and control were observed in terms of the increase in end-diastolic pressure or minimal diastolic pressure during balloon inflation. Mean systolic pressure decrease from baseline values was greater during control than during Fluosol inflations (-9.0 +/- 3.3 mm Hg, p = 0.013), but no significant difference was observed in the change in maximal rate of rise in left ventricular pressure (maximal positive dP/dt). These results suggest that Fluosol does not preserve global left ventricular diastolic function during coronary balloon occlusion, possibly because of its limited oxygen delivery capability relative to arterial blood. 