Objective To explore the optimal dose of intracoronary adenosine triphosphate( ATP) on fractional flow reserve( FFR) measurement. Methods FFR was assessed in 50 patients with 52 intermediate lesions. Different dose of intracoronary ATP[60 μg( IC1),100 μg( IC2),150 μg( IC3),200 μg( IC4),240 μg( IC5) as boli]were randomly administered. Then a intravenous infusion of 140 μg·kg-1·min-1was administered. FFR values,heart rate,blood pressure,systemic effects and so on were recorded. Results The FFR value decreased...