00:00
So, again, let’s talk a little bit about
the diagnosis by the electrocardiogram. Remember
the first thing is, you get a Gestalt, you
get an image, you then do a very very careful
analysis of the various intervals - Are they
appropriate? Is the heart rate appropriate?
Is the electrical activity and the heart moving
in the right direction? Do you see any abnormality
such as ST elevation, we talked about the
ST elevation, myocardial infarction? Are there
abnormalities in the T wave? You can also
diagnose increased heart volume because the
QRS has become very large. There's a whole
variety of diagnoses and they help the clinician.
00:43
The electrocardiogram is most helpful when
you know something about the patient. You
can then have taken the patient’s history,
the physical exam and you look at the electrocardiogram
and you bring those together in making a diagnosis.
Again, remember, that the computer diagnosis
is correct about 80% of the time, but wrong
20% of the time and particularly wrong when
it comes to diagnosing arrhythmias.
Very briefly, let’s talk a little bit about
treatment. Treatment is very complex. There
are a variety of medications, so called anti-arrhythmic
drugs which help to control all arrhythmias.
You can control atrial arrhythmias, you can
control ventricular arrhythmias. However,
these are medications that are associated
with the most side effects, the most adverse
side effects of any of the cardiac medications
we use. Remember, I mentioned Statin drugs
- very well tolerated, very few adverse events.
01:38
Anti-arrhythmic drugs are the opposite, there's
a lot of side effects in part because they
affect electrical activity. When they affect
the electrical activity in the heart, they
can also affect the electrical activity in
the brain and in the peripheral nervous system.
01:51
So, you may have side effects relating to
the fact that they are blocking electrical
activity in areas where you would prefer that
they not. Of course, pacemakers, I already
mentioned a number of times, that’s when
the heartbeat is missing in a particular area
either atria of the ventricle or both and
we put in a wire and a little box under the
skin that stimulates the heart so that there's
a normal rate. And actually, there's newer
pacemakers that actually can tell when you
start to exercise and they increase the heart
rate. Sometimes we use pacemakers to help
control arrhythmias and then of course, there
is the so called ablation where the cardiac
electrophysiologist go in with catheters and
they burn out areas that are causing arrhythmias
and sometimes they take several of these treatments
and often in combination with drugs, we can
obliterate and knock out the arrhythmia so
that the patient doesn’t have repeated visits
to the emergency room because of that.
02:52
So, in summary, I think I've made this point
a number of times, we have to overread the
computer reading very carefully, we have to
look at the Gestalt, the overall picture,
the pattern recognition and we have to look
carefully that each of the leads has been
done appropriately, that the direction of
the electrical impulse in the heart, that
the rate, that all of the waves are in the
normal position and if they're not, we need
to interpret how they're abnormal. Remember
that an experienced person needs to overread
the electrocardiogram and we need to interpret
the electrocardiogram often in the setting
of the clinical situation that the patient
is having. So, the patient with chest pain,
we’re going to be looking for changes that
suggest ischemia in the heart. In a patient
who has shortness of breath, we're going
to be looking for patterns that suggest hypertrophy
of the heart and so forth. The more clinical
information you have, the more intelligently
you will read the electrocardiogram. Even
minor changes on the electrocardiogram can
be important, particularly, for example, in
a patient with chest pain. Small changes in
the… the space between the QRS and the T
wave can suggest ischemia in the heart and
that’s what we look for, by the way, on
a stress test when we exercise the patient.
04:14
And finally, to reiterate one more time for
you, the computer EKG reading is helpful,
but it’s only accurate about 80% of the
time. And again, how do you learn to read
a cardiogram? The same way you learn to play
a musical instrument or play tennis - practice,
practice, practice. So, with this final
view of New York city from the Empire State
Building, we'll leave cardiac arrhythmias.
It’s an area that’s very interesting,
very common in clinical practice, requiring
a lot of experience to deal with and its something,
again, that’s become so complex that we
actually have special cardiologists that do
nothing else, but deal with arrhythmias every
day.