👉 The term "newtonic" is a medical term that refers to an abnormality in the heart muscle that can cause symptoms such as chest pain, shortness of breath, and discomfort. The term was first used by a doctor named Sir William Osler in 1875 to describe the condition. It describes a muscular contraction or dilation of the heart muscle during exercise, which can be caused by a variety of factors including stress, fatigue, and certain medications.