A rotational atherectomy system, comprising: an elongated, flexible drive shaft (20, 120) having a distal end for insertion into a vasculature of a patient and having a proximal end opposite the distal end remaining outside the vasculature of the patient; an eccentric solid crown (28,130) attached to the drive shaft (20, 120) proximate the distal end of the drive shaft (20, 120); an electric motor rotatably coupled to the proximal end of the drive shaft (20, 120), the electric motor being capable of rotating the drive shaft (20, 120) in a first direction and in a second direction opposite the first direction; and control electronics for monitoring and controlling the rotation of the electric motor, wherein the control electronics detect when the drive shaft (20, 120) and eccentric solid crown (28, 130) encounter a blockage in the vasculature that rapidly slows their rotation and control the rotational speed and torque of the drive shaft in response to the blockage, and wherein the drive shaft (20, 120) and eccentric solid crown (28, 130), when rotating, have a torque limited by a current supplied to the electric motor, wherein the control electronics include limits on maximum and minimum rotational speeds of the electric motor, wherein the control electronics include limits on maximum and minimum current supplied to the electric motor, wherein the control electronics include limits on maximum and minimum torque delivered by the electric motor. an elongated, flexible drive shaft (20, 120) having a distal end for insertion into a vasculature of a patient and having a proximal end opposite the distal end remaining outside the vasculature of the patient; an eccentric solid crown (28,130) attached to the drive shaft (20, 120) proximate the distal end of the drive shaft (20, 120); an electric motor rotatably coupled to the proximal end of the drive shaft (20, 120), the electric motor being capable of rotating the drive shaft (20, 120) in a first direction and in a second direction opposite the first direction; and control electronics for monitoring and controlling the rotation of the electric motor, wherein the control electronics detect when the drive shaft (20, 120) and eccentric solid crown (28, 130) encounter a blockage in the vasculature that rapidly slows their rotation and control the rotational speed and torque of the drive shaft in response to the blockage, and wherein the drive shaft (20, 120) and eccentric solid crown (28, 130), when rotating, have a torque limited by a current supplied to the electric motor, wherein the control electronics include limits on maximum and minimum rotational speeds of the electric motor, wherein the control electronics include limits on maximum and minimum current supplied to the electric motor, wherein the control electronics include limits on maximum and minimum torque delivered by the electric motor. wherein the drive shaft (20, 120) and eccentric solid crown (28, 130), when rotating, have a torque limited by a current supplied to the electric motor, wherein the control electronics include limits on maximum and minimum rotational speeds of the electric motor, wherein the control electronics include limits on maximum and minimum current supplied to the electric motor, wherein the control electronics include limits on maximum and minimum torque delivered by the electric motor.