Adenosine injection is a medication primarily used to treat certain types of irregular heartbeats, specifically supraventricular tachycardia (SVT). It works by slowing down electrical conduction in the heart, helping to restore a normal rhythm. Adenosine is often used in emergency situations when other methods fail. It can also be used in diagnostic tests to assess heart function or to trigger temporary pauses in the heart's rhythm for observation. Administered intravenously in a clinical setting, it acts quickly and is typically well-tolerated, though it can cause temporary side effects like flushing, shortness of breath, or chest discomfort.