Wow well welcome to another MedCram comm board vitals question this question
comes from the cardiology and family medicine question banks forty year old
male presents to your medical clinic to establish care he has no known prior
medical history and does not take any medications he complains of occasional
shortness of breath on walking more than two blocks he has never had any chest
pain he has never smoked and denies any
alcohol or drug abuse history he was adopted and does not know anything about
his parents or siblings he takes occasional multivitamins his
vitals in your office our blood pressure 110 over 80 heart rate 90 and he's in no
acute distress on physical examination he has a normal jvd clear lungs and a
harsh crescendo decrescendo systolic murmur that begins slightly after s1 and
is heard best at the apex and lower left sternal border ECG is shown below which
of the following is the best statement to describe further clinical management
a no further workup is indicated B echocardiogram is indicated which is the
correct choice C start furiosa might for diuresis or D start aspirin and plavix
now let's take a look at that ECG so what's the best answer well the first
thing we need to do is kind of go over the question stem and figure out what's
going on since we're on the ECG let's talk about that one first so this is a
12-lead ECG and i think the biggest thing that you'll notice without going
through rate rhythm and axis is these very large s waves in v1 and these very
large are waves specifically in v5 so if you actually look at these and count
them up you'll notice that the S wave and lead 1 v1 actually is let's see how
long it is that's about five millimeters 10 millimeters 15 20 25 almost 30
millimeters s wave and v1 and the R wave in lead v5 is let's count it 5 10 15 20
25 30 so the criteria area four left ventricular hypertrophy
is the S wave in lead v1 plus the R wave in lead v5 is greater together than 35
millimeters well we see it's about 30 in both so we're about 60 millimeters which
is well past the cutoff of the criteria for left ventricular hypertrophy so I
think that's what we're dealing with here so let's go back to the question
stem and see what else we can pick up we hear this harsh crescendo decrescendo
systolic murmur that begins slightly after s1 and is heard best at the apex
and lower left sternal border now this is kind of a classic type of murmur that
you would see with something called hypertrophic obstructive cardiomyopathy
where you have a sub a or text enosis that is actually very dangerous because
these people if they're ventricular size gets small enough and the subaortic
stenosis becomes great enough their cardiac output will fall drastically so
let's talk a little bit more about hypertrophic obstructive cardiomyopathy
the other name for this also that you may see is I H s s which is idiopathic
hypertrophic subaortic stenosis so this is the area that we're talking about
here here's the right atrium right ventricle left atrium left ventricle and
you can see here that the septum I'm drawing this kind of schematically here
is so hypertrophy that it's actually blocking the outflow tract that's going
to the aorta so normally what happens is is that the sound of a murmur or the
amplitude of the murmur is dependent on the amount of blood that's passing
through the valve and so therefore if the chamber
that's upstream from the valve that's creating the murmur is larger you're
going to get a larger sounding murmur so normally speaking if you're looking at
just regular a or t'k stenosis what will make a or text enosis go up in amplitude
will be anything that makes the ventricle larger that would be squatting
l the legs or a handgrip squatting because
when you squat more blood gets back to the heart because of the pressure and
therefore the left ventricle increases in size which causes the murmur of
aortic stenosis to increase elevating the legs causes more blood to come back
to the heart that's going to increase the size of the left ventricle and it's
going to do the same for now the way of thinking of this is that what we're
actually looking at is we're looking at sub a or text enosis not a or text
enosis and so in sub a or text enosis we're actually looking at the distance
right here if this distance gets smaller the stenosis is going to get worse and
therefore the sound or the amplitude of the sub a or text enosis is going to get
worse well that happens when the ventricle becomes smaller and so the
opposite maneuvers are going to make the murmur of subaortic stenosis get larger
and so as a result of that we see the arrows going in the opposite direction
okay so standing is going to make the heart smaller therefore these two are
going to come together more therefore the subaortic stenosis is going to
become worse a valsalva maneuver where you bear down causes less venous return
and that causes the left ventricle to get smaller and therefore sub a or
texture notices to get louder and then finally nitroglycerin it's going to
cause vasodilation that's going to cause the left ventricle to get smaller and of
course diuresis with lasix or furosemide is going to go ahead and do that and all
of these things that make the ventricle smaller are all things that could make
sudden cardiac death so these patients who have hypertrophy which is what we
saw on the EKG and I've never had any other kind of intervention they need to
have echocardiography to see whether or not the subaortic stenosis exists
because these are people that you don't want doing strenuous exercise because of
sudden cardiac death so again looking at this EKG we can clearly see here is a
very large s wave and here is a very large R wave and that's the key to left
ventricular hypertrophy and if we scroll on up and
take a look at the actual question we'll see in the question that
echocardiography is indicated and is the correct answer
why is no further workup indicated because if this person goes on to do
exercise he could die from sudden cardiac death if you're OSA might of
course as we talked about is not a good idea because it's going to make the
ventricles smaller and therefore more dangerous and starting aspirin and
plavix isn't going to have any effects on this portion of the heart it's just
going to prevent thrombosis in the coronary arteries so clearly the best
answer here is echocardiography which is indicated because this patients at risk
for having Holcomb thank you very much for joining us