A clinical programming system is disclosed for use with an implanted cardiac pacemaker to automatically determine the minimum pacing energy which is necessary to evoke a ventricular depolarization. The system utilizes a series of pacing pulses of progressively decreasing energies to stimulate the ventricle, and detects evoked responses through measurements of the integrals of the R-waves provided by a surface electrocardiogram. Upon loss of capture, the minimum pacing energy is a function of the energy of the last pacing pulse which evoked a ventricular depolarization.