Carotid sinus massage is a simple test that your doctor might perform to help determine the cause of your abnormal heartbeats (arrhythmias), such as atrial fibrillation or tachycardia. While monitoring your heart rate, your doctor may massage your carotid sinus, located at the side of your neck. This test is may be somewhat uncomfortable, but it is brief.

Rubbing the carotid sinus stimulates nerve endings, which can cause the heart rate to slow. This can help your doctor determine the cause of your arrhythmia.