👉 Tachymy is a medical term that describes an abnormality in the heart's pumping action. It can occur as a result of various conditions, including arrhythmias, which are irregular heartbeats or rhythms. Tachymy refers to a rapid heartbeat, often associated with atrial fibrillation (AFib), a condition where there is an abnormal electrical signal that causes the heart to beat faster than normal. Tachymy can be caused by various factors such as: 1.