About Heart DiseaseHeart DiseaseInappropriate Sinus Tachycardia (IST)- July 4, 2008 Inappropriate sinus tachycardia (IST) is a condition in which an individuals resting heart rate is abnormally high (greater than 100 beats per minute), their heart rate increases rapidly with minimal...http://heartdisease.about.com/b/2008/07/04/inappropriate-sinus-tachycardia-ist.htm |