Gallop rhythm is a medical term that describes an abnormal heart rhythm. This term is used to describe the sound of a horse galloping, as the heart rate is accelerated and irregular. Synonyms for gallop rhythm include tachyarrhythmia, atrial flutter, ventricular tachycardia, and atrial fibrillation. Each of these terms refers to a different type of irregular heartbeat. Tachyarrhythmia and ventricular tachycardia relate to fast-paced heartbeats that may be life-threatening. Atrial flutter refers to an irregular heartbeat in the upper chambers of the heart, while atrial fibrillation is a common type of irregular heartbeat that affects both the upper and lower chambers of the heart. Each of these synonyms for gallop rhythm is used to describe a heart condition that requires medical attention.