Tachycardia is a rapid heart rate of more than 100 beats per minute. Sinus tachycardia, from the heart's sinus node, is a normal response to exercise, illness, or stress.
There are several types of abnormal tachycardias or arrhythmias . These can come from two places:
* Atria (the two smaller chambers on the top of the heart)—called supraventricular tachycardias
* Ventricles (the lower chambers of the heart)—called ventricular tachycardia
This condition can be life-threatening. But, it can be treated. If you think you or someone you know has this condition, get emergency help.


