Mechanism for Bupivacaine Depression of Cardiac Conduction: Fast Block of Sodium Channels during the Action Potential with Slow Recovery from Block during Diastole

The effects of bupivacaine and lidocaine on cardiac conduction were compared in guinea pig ventricular muscle. Membrane potential was controlled using a single sucrose gap voltage clamp technique, and the maximum upstroke velocity of the action potential (Vmax) was used as an indicator of peak sodiu