Emotions have been connected to the heart throughout the ages, yet they have been largely discounted as playing an important role in heart disease. There is mounting evidence that anxiety, anger, depression, and stress play significant contributing roles in cardiac diseases. These emotional states, coronary artery disease, and heart failure have physiology consistent with the ongoing stress response characterized by parasympathetic withdrawal and sympathetic activation. Pharmacological therapies, vagal stimulation, and sympathetic ablation have shown efficacy in these diseases. Similar results can be obtained by biofeedback therapies.