Welcome back. Today we’re going to talk about hypertrophy that is growth in muscle mass patterns.
It turns out that these carry important clinical implications in the electrocardiogram
and we can recognize right ventricular hypertrophy and left ventricular hypertrophy with the electrocardiogram.
Now, the electrocardiogram is not quite as accurate as an MRI or an echo at recognizing these hypotrophy patterns
but when they are present, they usually mean that it’s quite severe and it carries major clinical implications.
We’re gonna talk about atrial dilation and we’re gonna talk about ventricular hypertrophy.
So everybody knows that the left ventricle has more muscle mass than the right ventricle
and therefore, it dominates the electrical activity of the ECG -
a left ventricular muscle mass as it increases the R wave voltage
increases reflecting this greater amount of LV muscle mass.
So, think about it for a moment. You have bigger myocardial cells in the left ventricle,
therefore, there’s more electrical activity,
therefore, the R wave voltage in the leads that reflect the left ventricle get greater.
We’re gonna see some examples in a moment.
Here are the ECG changes that occur with left ventricular hypertrophy,
often called LVH - tall R waves as I’ve just said that leads opposite the R waves are gonna have deep S waves,
often the QRS is slightly widened in other words more than 0.10 seconds.
Often, there’s left axis deviation that is the axis overall electrical activity of the ventricle maybe -45 or even -60.
Often, there can be STT changes, when there are STT changes with LVH
it means it’s more severe and that carries a poor prognosis.
And often we see left atrial enlargement because as the left ventricle hypertrophies,
the filling pressure in the left ventricle goes up resulting in dilation of the left atrium.
This is an example of left ventricular hypertrophy.
Notice first of all, that the R wave in lead 1 is very tall, in this case more than 13 mm.
Notice that the S wave in V1, V2 is very deep and the R wave is very tall in leads 4, 5, and 6;
in fact, there are a number of formulas that lead to the diagnosis via electrocardiogram of LVH
but in fact one of them is the S wave in V1, V2 plus the R wave in V5, V6 greater than 35 mm
if the patient is over age 30 and certainly if you add this up you’ll see it’s many more than 35,
it looks like about 20 and 20, so 40.
Another pattern that’s been associated with left ventricular hypertrophy is the R wave in AVL and the S wave in V3.
In this case, should be greater than 20 in a female
or greater than 28 in a male; in this case it doesn’t quite make it.
The computer has about five or six different algorithms for LVH
so the computer will read the LVH when you're looking at it and you're saying,
“Gee, it doesn’t look like LVH,” however, none of these is perfectly accurate but they do carry some clinical significance.
When LVH is seen on the ECG, it’s usually not a good sign.
It means that there's a presence of organic heart disease.
And here's another example of LVH; notice the high voltage in lead 1,
tall R wave just like we talked about and then notice again in V1 through V6, very deep S waves in V1, V2;
very high R wave in V5 and remember, if you added up the S wave in V1 to the R wave in V5,
it’s going to be many, many more millimeters than 35.
You also notice the inverted P waves in lead V1 with the final component the inverted,
the depressed component of the P wave, you’ll notice it’s usually wider than one box and deeper than one box,
that’s left atrium enlargement and in many of the LVH formulas that adds points to confirm the diagnosis of LVH.
So here we see another example. Look at lead V2 it has 5, 10, 15, 18 mm, now look at V5, 5, 10,
15, 20, 25, 30, 35 - so 35 and 18 is a lot more than 35 total so you've got in this case,
they saw 19 plus 35, 54 greater than 35, this is very suggestive of LVH.
Notice also that the T wave is inverted in lead V5
when that’s associated it usually means more marked LVH and a worse prognosis.
Here, look at this change, consider what you are seeing, tell me in your mind what you're seeing?
What I’m seeing is very large R waves in V5 and 6, with very deep S waves in V1, V2, V3 -
again, adding them up you're going to have an LVH.
Notice you also have down sloping ST segment and inverted T waves;
again, as I've mentioned, this is a finding that says more severe LVH and a poor prognosis.
What about this ECG? Note, large voltage in lead 1, large voltage in V3,
large S wave voltage in lead 3, large R wave voltage in lead AVL.
Again, this is left ventricular hypertrophy - lots of muscle mass in the left ventricle.
So, what about right ventricular hypertrophy? Well, right ventricular hypertrophy,
remember, we talked about this in the first lecture.
The right precordial V1 electrode is very much over the right ventricle
cuz the right ventricle is right under sternum so right ventricular hypertrophy
is usually shown by an increase in the R wave in lead V1.
Remember, we talked about an LVH, the increase R wave voltage is in V5, 6;
but here with right ventricular hypertrophy, the increase voltage is in lead V1
and of course the right ventricle almost always has less muscle mass compared with the left ventricle
so the R wave is not as impressive; the increased R wave in V1 not as impressive
as the increased R wave in V5 and 6 and we’ll look at some examples in a moment.
So here all of the kinds of changes you can see with RVH, first of all taller R wave in V1.
Normally, a patient who has a normal cardiogram won’t have an R wave more than 1 or 2 millimeters in V1,
if it’s fairly big and particularly if it’s bigger than the S wave that suggest right ventricular hypertrophy.
There are often deep S waves in the lateral leads that is leads 1 and AVL,
also reflecting the increased RV voltage, and often there’s a right axis deviation greater than 90 degrees
so the axis deviations is going somewhere down this way and often there is a tall peak P wave greater than 2 mm,
that’s right atrium enlargement; so just as left atrial enlargement accompanies LVH,
right atrial enlargement accompanies RVH.
And here's some examples. First of all notice how tall the R wave is in the green box in lead V1.
This is actually a patient with pulmonic stenosis that leads too very significant increase
in right ventricular mass and therefore, large R wave in V1.
Notice the deep S wave in lead AVL, we mentioned before again reflecting RV hypertrophy.
You'll notice that there's right axis deviation.
Look, the maximum R wave in this case is in AVR,
it’s somewhere way up here so that’s a huge right axis, the right axis deviation all away around
to here and you can see that there's almost no R wave in lead 1, 2, and 3 is perpendicular, right?
So, it’s probably 90 degress from 120 or +210 which is AVR, and that’s where the maximum R wave is
and then notice the tall P waves in the little black box, these tall spiked P waves are right atrial enlargement
and you can also see them in lead V2 and V3.
So here's another example, tall R waves at the green box in lead V1 and notice tall P wave,
very tall spiky P waves in leads 2 and in lead V2,
again, right atrial enlargement and right ventricular hypertrophy.
Again, another example, notice the tall R wave in lead V1
and you’ll notice there's a widen QRS out in the right - in the precordial leads out of V6
with a big deep S wave that’s reflecting the big R wave in lead V1
again an example of right ventricular hypertrophy and there's also again look at the limb leads, there's right axis deviation.
The maximum R wave voltage here is between leads 3 and AVR so it’s something like 180+ so right axis deviation,
increased R wave in lead V1 and big, broad S wave in V6, right ventricular hypertrophy.
Here we see a patient with both left ventricular hypertrophy and right ventricular hypertrophy.
Let’s look at the findings. First of all, look at the voltages in leads V4, 5, and 6,
you’ll see pretty much very high voltages there that also are reflected in the limb leads, look at the tall voltages in 3.
Also, notice though that it’s a predominant R wave in V1 so wait a minute,
this is looking like there's both left ventricular hypertrophy and right ventricular hypertrophy.
So you notice lots of volts over the left precordial leads and lots of voltage over the S1,
the tall R wave so this suggests that there's both right ventricular hypertrophy and left ventricular hypertrophy.
If you also look in the green box that’s showing you lead 1 and 2, notice the tall spiky P waves -
right atrial enlargement. So again, we're dealing with a patient here that has both left ventricular
and right ventricular hypertrophy, not seen very commonly, but definitely there.
And here we show you again the right atrial enlargement in the black box.