To evaluate the effects of epinephrine (E) and norepinephrine (NE) administered during local anesthesia on left ventricular diastolic function, we examined transmitral inflow patterns with pulsed Doppler echocardiography. Arterial blood pressure, heart rate, and transmitral inflow patterns were measured in 10 healthy volunteers when 3.6 mL of 2% lidocaine containing 1:80,000 E or 1:25,000 NE was injected supraperiosteally in the maxilla. The dosage of drug administered was 45 micrograms for E and 144 micrograms for NE. After the administration of E, heart rate was increased, but blood pressure was unchanged. Peak early velocity (R), peak atrial velocity (A), the ratio of A to R (A/R), and the deceleration rate (Dc) were increased, whereas the isovolumic relaxation time (IVRT) was shortened. The increase of R and Dc and the shortening of IVRT indicated an activation of left ventricular relaxation. After the administration of NE, blood pressure was increased and heart rate was decreased. A decrease in Dc, shortening of the acceleration half-time (AcT), and prolongation of IVRT were observed. These changes reflect impeded myocardial relaxation. We conclude that E activates left ventricular diastolic function and that NE, in contrast, impairs it.