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One of the most common causes of palpitations is the skipping of the heartbeat that occurs from extra beats. These are simply extra beats that occur in all of us, but are felt more in some because they are more frequent. Most of the time these are simply beats from a secondary pacemaker in the heart that creates irregularity in the pulse that feels unusual. Typically, patients describe these as brief perturbations of the heart rhythm. The heart is otherwise normal, and the beats themselves are of no prognostic importance.
The heart has a single dominant pacemaker called the sinus node. There are several sites within the heart that are additional pacemakers that at times can be overactive. These sites can produce skipped beats that may occur as infrequently as 50 times a day, or as often as thousands of times a day. These do not normally represent anything serious, but can produce new symptoms when a sense of irregularity occurs. Patients will often describe the feeling of "heart jumping, flipping or missing", with forceful beating after the skipped beat. This is illustrated in the adjacent figure, where the heart beat is regular followed by a skipped beat. After a short pause, there is a normal beat again. The pulse that this produces is illustrated below the trigger of the EKG and the figure. The normal pulse is followed by a very small pulse from the skipped beat. This is the sense of missing or skipping that occurs where the patient may feel the heart "stopping". This is followed by a very forceful beat when in effect two heart beats are pumped out at once or the volume of two heart beats is pumped out all at once with the resumption of normal rhythm. This often leads to the sense that the heart skips or "misses count", followed by a forceful pounding or impact in the chest with the normal beat.
This condition is benign, and is often an exaggerated version of the normal number of skipped beats that occurs in every person. Skipped beats are more common with any type of stimulant, including caffeine, decongestants, alcohol, bronchodilators (puffers for asthma) and occasionally with stress. Patients might find that modifying their lifestyle with respect to these agents reduces the frequency of skipped beats. |