Browse our Health Library to learn about treatments, conditions, and how Cedars-Sinai can support your healthcare needs.
Inappropriate sinus tachycardia (IST) is a health problem in which the heart beats very quickly without a good reason. It is a type of heart rhythm abnormality called an arrhythmia.
An ICD helps people with serious heart rhythm problems. It sits in the chest, and sends a shock to the heart when it senses an abnormal rhythm. See how it works, and how it saves lives.