Premature heartbeats occur when the heart's regular rhythm is interrupted by early or premature beats. It may feel as if the heart has skipped a beat. Usually it is not serious. If the beat arises from locations in the atria (upper chambers) it is called premature atrial contraction (PAC). Premature ventricular complexes (PVC) arise from the ventricles (lower chambers).
Premature Atrial Contraction (PAC)
Irregular heart rhythms are most often caused by premature beats or extra beats. These originate in the upper chambers (premature atrial contraction, PAC). When we feel our heart "skip a beat," it usually results from this type of arrhythmia.
The heart does not skip a beat. Instead an extra beat comes sooner than normal. This is followed by a pause that causes the next beat to be more forceful. The person feels this more-forceful beat.
Premature beats are common in healthy people of all ages- most people have them at some time. Caffeine, alcohol, stress and fatigue may cause PAC's to occur more frequently. Usually no special treatment is needed and no cause can be found. The premature beats may disappear, and even if they continue, most people tolerate them well.
Premature Ventricular Complexes (PVC)
An electrical signal from the ventricles causes an early heart beat that generally goes unnoticed. The heart then seems to pause until the next beat of the ventricle occurs in a regular fashion. Premature beats are common in healthy people of all ages- most people have them at some time. Usually no special treatment is needed and no cause can be found. The premature beats may disappear, and even if they continue, most people tolerate them well. Occasionally PVC's may be caused by disease or injury to the heart. Sometimes, PVC's are very frequent with overwhelming symptons, and rarely a cause of weakened heart function. Treatment with medication or ablation may be required.