An apparatus for measuring a performance metric of a heart includes a housing, a tactile sensor, a finger clamp, a linear actuator, and a controller. The tactile sensor measures blood pressure pulsatility in a digital artery of a finger via applanation tonometry and outputs pulsatility signals indicative of the blood pressure pulsatility. The finger clamp extends from the housing to clamp the finger against the tactile sensor with the digital artery aligned over the tactile sensor. The linear actuator drives the finger clamp with a clamping force directed along a linear path. The controller is coupled to the tactile sensor and the linear actuator to control the clamping force and to generate pulsatility data, based upon the pulsatility signals, from which the performance metric of the heart may be determined.