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

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:

 

Diagnosis

Evaluation is similar as with any patient first seen for palpitations  and arrhythmias and includes blood tests, EKGs, as well as echocardiograms.

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.