An apparatus includes a body, a shaft assembly, and an end effector. The end effector includes an ultrasonic blade and a clamp arm assembly. The ultrasonic blade is in acoustic communication with an acoustic waveguide of the shaft assembly. The clamp arm assembly is pivotable toward and away from the ultrasonic blade. The clamp arm assembly includes a first electrode and a second electrode. The first and second electrodes are operable to cooperate to apply bipolar RF energy to tissue.