The normal heart rhythm is controlled by something called the sinus node, a tiny structure located near the top of the right atrium in the heart. ( Read about the normal cardiac electrical system here.) The sinus node normally "discharges" the electrical signal that controls the heart rate 50 to 90 times per minute (while you are at rest).
But a condition known as premature atrial complexes - PACs - can throw off this rhythm. If you have been diagnosed with a PAC, rest assured: It is quite a common condition. In fact, if you recorded the heart rhythm of 100 normal people for 24 hours, more than half would have at least a few PACs.
What Causes PACs?
PACs are caused by early (or premature) electrical signals that can be produced from different locations within the atria. Essentially, a PAC is an early heart beat.In most cases, PACs do not cause any symptoms at all. However, some individuals can experience mild palpitations associated with PACs. After ingesting alcohol, tobacco, caffeine, or medications containing stimulants, PACs can increase in frequency and can produce more palpitations.
PACs almost never require treatment, except avoiding the substances that can make them occur more frequently.
