A medical assembly, comprising: a prosthetic heart valve that is radially expandable and compressible between a radially compressed configuration and a radially expanded configuration; and a delivery apparatus comprising: a handle, at least one first actuator extending from the handle and coupled to a proximal end portion of the prosthetic heart valve, wherein the at least one first actuator is configured to apply a distally directed force to the proximal end portion of the prosthetic valve; at least one second actuator extending from the handle and coupled to a distal end portion of the prosthetic valve, wherein the at least one second actuator is configured to apply a proximally directed force to the distal end portion of the prosthetic valve; a sensor; a first motion-transmitting member having a distal end portion coupled to the at least one first actuator and a proximal end portion coupled to the sensor; and a second motion-transmitting member having a distal end portion coupled to the at least one second actuator and a proximal end portion coupled to the sensor; wherein the prosthetic heart valve is radially expandable from the radially compressed configuration to the radially expanded configuration upon actuating the at least one first actuator and the at least one second actuator to apply the distally directed force and the proximally directed force, respectively, to the prosthetic heart valve; wherein the sensor senses relative movement between the first and second motion-transmitting members (214, 216) upon actuation of the at least one first actuator and the at least one second actuator to determine the diameter of the prosthetic heart valve as it is expanded. a prosthetic heart valve that is radially expandable and compressible between a radially compressed configuration and a radially expanded configuration; and a delivery apparatus comprising: a handle, at least one first actuator extending from the handle and coupled to a proximal end portion of the prosthetic heart valve, wherein the at least one first actuator is configured to apply a distally directed force to the proximal end portion of the prosthetic valve; at least one second actuator extending from the handle and coupled to a distal end portion of the prosthetic valve, wherein the at least one second actuator is configured to apply a proximally directed force to the distal end portion of the prosthetic valve; a sensor; a first motion-transmitting member having a distal end portion coupled to the at least one first actuator and a proximal end portion coupled to the sensor; and a second motion-transmitting member having a distal end portion coupled to the at least one second actuator and a proximal end portion coupled to the sensor; a handle, at least one first actuator extending from the handle and coupled to a proximal end portion of the prosthetic heart valve, wherein the at least one first actuator is configured to apply a distally directed force to the proximal end portion of the prosthetic valve; at least one second actuator extending from the handle and coupled to a distal end portion of the prosthetic valve, wherein the at least one second actuator is configured to apply a proximally directed force to the distal end portion of the prosthetic valve; a sensor; a first motion-transmitting member having a distal end portion coupled to the at least one first actuator and a proximal end portion coupled to the sensor; and a second motion-transmitting member having a distal end portion coupled to the at least one second actuator and a proximal end portion coupled to the sensor; wherein the prosthetic heart valve is radially expandable from the radially compressed configuration to the radially expanded configuration upon actuating the at least one first actuator and the at least one second actuator to apply the distally directed force and the proximally directed force, respectively, to the prosthetic heart valve; wherein the sensor senses relative movement between the first and second motion-transmitting members (214, 216) upon actuation of the at least one first actuator and the at least one second actuator to determine the diameter of the prosthetic heart valve as it is expanded.