Lauren R. answered 10d
EMT, Medical Assistant, Bachelor of science degree
Tachycardia essentially means a fast heart rate, over 100 beats a minute. A normal, resting heart rate should beat between 60 and 100 times per minute. "Tachy", meaning fast, "cardia" meaning heart, is when the heart rate of an individual is beating faster than 100 beats per minute.
The sinoatrial node (SA node) signals how often your heart beats. Factors such as age, fitness level, anxiety, etc. will affect your heart, sending signals more frequently, resulting in a fast heartbeat.
To get more complex on this subject, there are three types of tachycardia. Sinus tachycardia is a normal response to exercise, where the heart is working harder, beating faster, but the heart is beating how it should be. Supraventricular tachycardia takes place when the upper chambers of the heart stops filling with blood, limiting blood flow to the rest of the body. This type if rarely life-threatening. However, ventricular tachycardia starts in the lower chambers of the heart, causing the heart to beat so quickly that the chambers cannot fill with blood. This type can be life-threatening, requiring the care of a heart expert.
Hope this helps.