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“MY HEART SKIPS A BEAT”
The complaint of “extra” or “skipped beats” is a common one and is
taken seriously by cardiologists. The sense of skipping or dropping of the heart is may be
benign. After evaluation, the source commonly turns out to be related to lifestyle issues
rather than any serious underlying heart disease. This conclusion, however, is not reached
until more serious causes are excluded by testing.
Do you remember sitting in school and having the teacher announce a
pop quiz? At that moment, you probably felt your heart pounding inside
your chest. This would have been a natural reaction to the release of
adrenaline into your blood stream. Among other effects, adrenaline makes our
hearts pound harder and faster to deal with a perceived threat. In primitive
times, this boost in heart function would allow us to run faster and farther
from a predator. In modern times, we have other reasons for adrenaline
release: job or domestic stress, sleep deprivation, caffeine or alcohol use.
These stressors can produce unusually rapid or irregular heart beating.
Palpitation is the name doctors give to a patient’s symptom of
skipping or rapid heart beat. Persistent palpitation associated with dizziness,
shortness of breath or chest pain definitely warrants evaluation. After taking
your history and performing a physical examination, your doctor will
commonly perform several tests. These include taking a blood sample, applying a Holter
device for monitoring of the heart beat over 24 hours, and performing an
echocardiogram.
The blood sample is taken to exclude chemical causes of extra beats.
In this category, we sometimes find low potassium (hypokalemia) levels or
elevated thyroid hormone levels (hyperthyroidism).
The heart monitor is a small device that can be worn during a day of
normal activity including a usual work out. Electrodes are attached to the
skin of the chest to provide a walking or ambulatory EKG. Most of these devices
have a clock and an “event button” which patients are asked to push when they feel
a skipped heart beat. Pressing the button puts a mark on the recording and
allows the physician who reviews the recording to see what was going on at
the instant the patient had symptoms. When the patient brings the
recorder back the next day it is analyzed at 60 times normal speed and
sample EKG’s are printed out for physician review. From the cardiologists’
point of view, palpitation that is accompanied by normal heart recordings
may signify “cardiac consciousness” or awareness of our normal heartbeat,
which taken with other evidence can lead to the conclusion of a benign
diagnosis. In these instances, elimination of the adrenaline releasing stressors
mentioned above can be helpful.
In some instances, we find that the symptom of a skipped heartbeat is
just that, a beat from the top (atrial) or bottom (ventricular) heart chamber
that occurs prematurely or earlier than it was expected to fall in the normal cycle.
These atrial premature contractions or ventricular premature contractions (also known as
“APC’s” or “PVC’s “) represent an extra electrical signal that causes the heart to
contract earlier than normal. When the extra beats occur in a sequence of 3
in a row or more and the heart rate is greater than 100 we refer to these
rhythms as atrial or ventricular tachycardia. In general, the faster and more
prolonged these episodes are, the more likely the patient is to experience
other symptoms such as shortness of breath, lightheadedness or even loss
of consciousness.
The echocardiogram is a key component for evaluating the symptom
of palpitation. Cardiologists oftern think of the the beating heart in terms of the
component parts—almost like those in an automobile. If the ignition system
of a car goes awry, we don’t think of discarding the entire car! Rather, we
see to servicing the spark plugs, ignition timing, etc. Likewise, the
heart has its own ignition system, known as the sinus node , which is our natural
pacemaker. Other components include the receiving and pumping chambers, valves,
coronary arteries and the heart muscle itself. The electrocardiogram allows us to assess
the electrical or ignition system of the heart and the echocardiogram gives detailed
information about the mechanical heart components.
Aging pacemakers, leaky valves, enlarged or thickened chambers, and
weakened or damaged heart muscle can all give rise to different kinds
of abnormal rhythms. Fortunately, modern cardiology has a many remedies
to offer the patient with palpitation. For more information, please
refer to specific articles in our Patient Learning Center.
Kenneth Krauss, MD FACC
The opinions expressed in this article are solely those of the author and are not
necessarily those of his affiliated organizations.