The heart normally beats at a rate of about 60 to 100 beats per minute at rest. A rate faster than 100 beats a minute in an adult is called tachycardia. Most people experience transient rapid heartbeats, called sinus tachycardia, as a normal response to excitement,
The two main types of tachycardia are abnormal supraventricular tachycardias (which originate in the upper...
Detective Ferguson climbs tentatively to the top of the step-ladder. Nervous and perspiring, he is completely overwhelmed when he reaches... Read more »
What we call normal rhythm is stimulated by a group of cells in the upper chamber of our heart called the atrium. This group of cells is in... Read more »