Abstract: A post-extrasystolic potentiation (PESP) cardiac pacing energy stimulator for applying paired and/or triggered pacing stimulation pulses to the right atrium and/or ventricle incorporating one or more sensors, such as a venous oxygen saturation, ventricular, atrial, or arterial blood pressure, or intracardiac or systemic blood flow sensor, and signal processing circuitry for controlling the frequency of or number of heart cycles between periodic delivery of triggered or paired pacing to induce PESP for the treatment of congestive heart failure or other cardiac dysfunctions. Preferably, a first sensor, e.g., a ventricular or arterial blood pressure or flow sensor, is employed to monitor the performance of the heart, and develop a cardiac performance index (CPI) and a second sensor, e.g., an oxygen saturation sensor positioned in the coronary sinus, is employed to monitor cardiac muscle stress and develop a cardiac stress index (CSI) to balance performance and stress.