The present disclosure provides an apparatus and method of optimizing a pacing heart rate. The method can include obtaining a preload-frequency relation and a force-frequency relation from histogram data for a patient condition and determining an optimal pacing heart rate for the patient condition. The optimal pacing heart rate can be substantially between a first heart rate corresponding to a minimum preload condition based on the preload-frequency relation and a second heart rate corresponding to a sustained ionotropic reserve condition based on the force-frequency relation.