Abnormally rapid heartbeats caused by reentry circuit in or around the SINOATRIAL NODE. It is characterized by sudden onset and offset episodes of tachycardia with a HEART RATE of 100-150 beats per minute. The P wave is identical to the sinus P wave but with a longer PR interval. The disease is sinoatrial nodal reentry tachycardia (Experimental Factor Ontology id EFO_1001843). Also known as: AV nodal reentry tachycardia, Tachycardia, Sinoatrial Nodal Reentry, atrioventricular nodal reentry tachycardia.