The extra beat may be from the atria of the heart, or from the ventricle.
In the former case, the space between the extra beat and the next beat is
the same as the normal interval.  Atrial extra (ectopic) beats are common, usually asymptomatic. No therapy is indicated unless they are extreemly frequent, and
then decreasing caffiene intake, or stopping use of decongestiant cold
remedies may result in resolution.  It could be a normal situation.  It is known
that the heart rate will follow the respiration, so called "sinus arrhythmia".
If your heart speeds up during inspiration and slows during exhalation, that is the problem.  This is very common in the young, and tends to disappear (usually)with ageing.
If the ectopic beat occurs from the ventricle of the heart, the situation
could be more significant.  Again, it could be caused by such benign things as
coffee, {*filter*}, decongestants.  However, the significance of the arrhythmia
is more dependent on how close the extra beat comes to the preceeding normal
beat.  If it is too close, there is potential for what is called sustained
ventricular arrhythmia (ventricular tachycardia, or ventricular fibrillation).
So, if simply stopping any of the above listed predisposing factors does not
help, you should have an electrocardiogram to determine exactly what is happening, and if therapy is necessary.
This could be nothing, or have the potential for cardiac arrest.

Kevin W. Tibbs

: I, too, experience this phenomenon.  Wouldn't this be more appropriately
: refered to as paroxysmal tachycardia?

The original post makes no mention of an increase in heart rate, only
of an occasional irregularity of beat; thus I don't think it's appropriate
to label it a tachycardia, although various kinds of tachycardias can
follow such an extra beat in some people.  Some people are quite sensitive
to coffee. You might want to give it up and see if it makes a difference.
Checking with your own doctor would be a good idea too, since advice
on the Internet should be taken with a grain of salt at all times.

There are several places in the heart where electrical impulses can
originate.  The usual place is the sino-atrial node.  It is also
possible for beats to originate from other areas of the heart.  
Ventricular arrthymias are those that originate from the ventricles
of the heart. (If you have questions about the terms you should
consult an anatomy textbook)  Ventricular arrthymias have the
potential to be quite serious if the  person also has heart
disease.  Many people who are healthy do have occasional extra
beats originating from the ventricles, called PVCs or premature
ventricular contractions.  It is more serious if a person has
several ventricular beats in a row, or if they occur in two
or three beats at a time, since this can trigger a potentially
very dangerous arrthymia called ventricular tachycardia.

Not all arrthymias are ventricular.  There are many that originate
in other places in the heart, and the only way to tell for sure
where they are coming from is to do an EKG.

--

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     Shrine of the {*filter*}netic Madonna BBS      213-766-1356
              "The BBS for the information {*filter*}!"
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I have the same problem and so does my Dad. I wonder if there's a
connection. I always thought I had this occur at least once a day, but I
wore a holter monitor once and it didn't pick up any.

I seem to be very sensitive to caffeine. One cup of coffee everyday is
enough to notice it after a few days. One cup every three or four days
does not seem to be as noticeable. I've also had more problems with {*filter*}
that may interact with each other, for example asthma medicines and
decongestants.

--
____________________________________________________________________________
Carly Rothman                  "The voyage of the best ship is a zigzag

                /\/\/\/\_____/\/\/\____/\/\/\/\/\/\___
____________________________________________________________________________

: >The original post makes no mention of an increase in heart rate, only
: >of an occasional irregularity of beat; thus I don't think it's
: appropriate
: >to label it a tachycardia, although various kinds of tachycardias can
: >follow such an extra beat in some people.

: My rate avgs 80, but it often speeds up to 100-110 for no reason I can
: tell (i.e. not following a high level of physical exertion).

There's a lot of reasons why a person's resting pulse can increase.  (I
assume it's resting from your description).  If this happens after the
irregular heart beat that you mentioned before, then you could have
the paroxysmal tachycardia that another poster mentioned.  That would
be from that extra beat coming right on the heel of or right before
a regular beat, and that can trigger a kind of feedback loop, where
the electrical impulse keeps getting sent back to the atrioventricular
node and then bounced right back again.  The atrioventricular node
is the second stop in normal heart conduction.  Normal heart beats
originate in the sino-atrial (SA) node, which is over the
right atrium of the heart.  The SA node sends it on to the atrio-
ventricular node (AV), which then sends it out to the rest of the
heart.  You can have either an impulse from the
SA node hit the AV node and get bounced back or an impulse from
the ventricles.

It can also happen from eating a heavy meal, certain {*filter*} chemicals
such as adrenalin and cytokines (which are immune response chemicals),
medications, coffee, etc.  There's no way to know what's going on
in your own case without running an EKG.  YOu might even need to
have your heart rate recorded for 24 hours with a Holter monitor.

Most doctors don't treat these kinds of tachycardias unless they
are also causing signs of decreased {*filter*} circulation like light
headedness.  However, if it turns out that what you're having
is runs of ventricular tachycardia, then you need to be closely
monitored by a cardiologist, because this kind of rhythm is potentially
dangerous.

I think that if you're not just having an occasional irregular beat,
but also runs of elevated heart rate, that you should go have this
checked out by a doctor.

--

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     Shrine of the {*filter*}netic Madonna BBS      213-766-1356
              "The BBS for the information {*filter*}!"
-----------------------------------------------------------------------

I agree with some of the posters concerning the foci of ectopic beats
within the myocardium,  but what about pathways from an irritated cardiac
sphincter of the esophagus, especially after drinking 2 cups of coffee
on an empty stomach?
---
Al Bledsoe
NationsBank

Dysfunction of the cardiac sphincter of the esophagus will cause "esophageal
reflux", essentially the sour burps or the "hyperacidity" problem that occurs while lying down.