Source:http://linkedlifedata.com/resource/umls/id/C0039234
MSH: Abnormally rapid heartbeats originating from one or more automatic foci (nonsinus pacemakers) in the HEART ATRIUM but away from the SINOATRIAL NODE. Unlike the reentry mechanism, automatic tachycardia speeds up and slows down gradually. The episode is characterized by a HEART RATE between 135 to less than 200 beats per minute and lasting 30 seconds or longer.,NCI: Atrial tachycardia that does not originate from the sinoatrial node.