- Your Heart
- Ask Dr. T
- Heart Healthy Living
- About Us
- Contact Us
Premature Atrial Contractions (PACs)
Premature Atrial Contractions (PACs) are amongst the most common forms of arrhythmias. It is due to the premature discharge of an electrical impulse in the atrium, causing a premature contraction.
Therefore, it is named "premature atrial contraction," or PAC. A PAC is premature, because the it occurs earlier than the next regular beat should have occurred.
Symptoms of PACs
Most often, patients with PACs complain of palpitations. However, rather than reporting sustained racing heartbeat, they usually describe "missing" or "skipping" of the heartbeat. Some patients even feel that the heart has "stopped" while others describe a sensation of "flip-flop." This is due to the fact that the PAC comes too early (prematurely) in the cardiac cycle to have resulted in an effective pulse or heartbeat. Therefore, no heartbeat is felt until the next regularly-timed heartbeat occurs after a pause (so-called compensatory pause). Incidentally, the beat after the PAC usually occurs with stronger contraction than usual and can be associated with an urge to cough. Symptoms of PACs are virtually indistinguishable from those of PVCs as the physiological effects are identical.
Causes of PACs
- Underlying Heart Disease
- Abnormal blood levels of magnesium and/or potassium
- Digitalis toxicity
In the majority of cases, PACs occur in normal healthy individuals without any evidence of heart disease. Stress or stimulants such as tea, coffee, or alcohol can increase the frequency of PACs. In the minority of cases, PACs can be a sign of underlying heart condition in the atrium associated with hypertension or valvular condition.
Consequences of PACs
The great majority of PACs are completely benign and require little if any treatment at all. As mentioned above, in rare cases, PACs may be the only sign of underlying heart conditions and these should be ruled out with appropriate evaluations. However, PACs may change into
- Atrial Flutter:
Treatment of PACs
As most PACs are benign, treatment is optional and is usually geared toward alleviation of symptoms. Medications such as beta blockers or calcium blockers are often used but with mixed result. Most important treatment, after ruling out severe underlying heart conditions, is patient reassurance and teaching of various coping mechanisms.
Ask Doctor T. Blog
My 12 yr old son (140cm, 38kg) had a recent episode last month of sudden fainting, hit the back of his head on the concrete at high speed. Was unconscious for under a minute. Went to emergency via ambulance and his ECG showed QT prolonged 492ms. Question 1.Could the knock on his head of caused this ? (he did have a previous episode of unconsciousness but it was...