doing this all the time, not somebody who
just does one on occasion. You don’t, of
course, want to remove too much of the septum.
Well, let’s talk about the much, much less
common cardiomyopathies. Restrictive cardiomyopathy
is almost not seen very much in developed
countries. It’s a little more common in
developing countries where people have poorer
nutritional status. It is a infiltration of
the myocardium, usually with a substance that
makes the ventricle quite stiff. The commonest
one in developed countries is amyloidosis.
This is an abnormal protein that gets deposited
in the heart and makes the heart stiff. And
that’s why it’s called restrictive. The
heart restricts filling because of this deposition
of protein in between the myocardial cells.
By the way, amyloidosis can also affect the
kidney, so the patients can have kidney failure.
It’s a very bad disease, often treated with
chemotherapy like a cancer because it’s
usually due to a group of immune cells that
are producing much too much of an immune substance
in the blood and this immune substance gets
into the tissues of the heart, the kidney
and so forth. It’s called amyloid protein
and it causes a marked stiffening of the heart
muscle. It has a poor prognosis, again because
we first see these patients when they usually
have well-developed heart failure; in other
words, they’re at a very advanced stage.
And the treatment - once you try some drugs,
the mainstay is diuretics to try and get rid
of the excess fluid. Beta blockers, ACE inhibitors
don’t work in this form of cardiomyopathy
and a number of these patients go on to a
heart transplant. These patients can have
a lot of arrhythmias as well and can have
sudden death. The commonest form, again, in
the West here, is amyloidosis.
Now, here you can see the same little diagram
we’ve seen before. On the left-hand side
is the normal heart and you can see on the
right-hand side, there’s a slight thickening
of the ventricle. But, what’s really happening
here is that the ventricular muscle is being
infiltrated with a substance that’s causing
it to be restrictive. Sometimes when the pericardium
is scarred or injured and gets thickened,
it can be hard to distinguish that from a
restrictive cardiomyopathy since the physiology
is the same - a thickened, stiff pericardium
grips the heart and impairs its filling, just
as restrictive myopathy does so. And often
we need to do MRI and a variety of catheterization
tests to decide, “Is this constrictive pericarditis
or is this a restrictive myopathy?” Why
is that important? Because there’s a surgical
operation to remove the pericardium and make
the patients much better whereas in restrictive
cardiomyopathy, the eventual treatment is
This slide just reiterates what I said before.
Amyloid is the commonest form in the West
of restrictive myopathy. The diagnosis is
made usually by echocardiography and the MRI
helps us distinguish restrictive myopathy
from constrictive pericarditis. This is not
a very common thing. In my very busy cardiology
hospital, we might see one or two of these,
perhaps three patients a year whereas coronary
disease is multiple events every day and dilated
cardiomyopathy or hypertrophic cardiomyopathy,
we see every week. So, you can see a sort
of relative experience of the cardiologist.
This is not very common.
And again, treatment - you do the best to
keep the patient’s excess fluid on board
down with diuretics, but in fact, the prognosis
is usually quite poor and these patients may
end up, if they are appropriate candidates
in other respect, requiring a heart transplant.
A final type of cardiomyopathy that’s quite
rare is called “ARVD” or “arrhythmogenic
right ventricular dysplasia” cardiomyopathy.
What is this? This is a very unusual form
of cardiomyopathy in which the right ventricular
muscle is gradually replaced by fat and scar
tissue leading eventually to both severe right
ventricular failure with symptoms of congestion
in the liver and the abdomen and peripheral
edema - peripheral swelling and in addition,
malignant ventricular arrhythmias that often
lead to sudden death. Fortunately, this is
a rare cardiomyopathy, but it’s of great
interest to scientific investigation because
it may give us clues as to why the heart muscle
cells are disappearing and dying and perhaps
we might be able to reverse it and maybe some
of those techniques might be used in other
forms of cardiomyopathy. The treatment unfortunately
consists mostly of diuretics to control the
edema and then implantation of a cardioverter–defibrillator.
So, when the patient develops a malignant
ventricular arrhythmia, they will be shocked
out of it and will not have a sudden death.
A number of these patients go on to, of course,
heart transplant. It’s genetically transmitted
in families, and as I said, even though it’s
rare, there’s a great deal of scientific
interest in this particular form of cardiomyopathy.
What happens here in this rare form of cardiomyopathy
is something that’s of great interest to
scientists who are studying the forms of cardiomyopathy.
These individuals are usually born normal.
They develop normally and then as they age,
progressively the right ventricular heart
muscle is replaced by fat and scar tissue.
It’s a genetic cardiomyopathy. The underlying
mechanism is not totally understood, but what
happens is these patients go on to develop
severe right ventricular failure. Remember,
that’s with elevated neck veins, fluid in
the abdomen, fluid in the legs. The left ventricle
is often normal although occasionally affected,
but it’s mostly the right ventricle that’s
affected. And what happens is these patients
develop malignant ventricular arrhythmias
and sudden death and they often need treatment
not only for their heart failure, but also
they need an implantable defibrillator. In
case they develop ventricular fibrillation
cardiac arrest, it will shock them out of
it. It’s very uncommon, but in fact, is
the source of a lot of scientific investigation
because if we could understand some of the
mechanisms - why the heart cells disappear
and fat takes their place, it might help us
to understand what’s going on in some other
forms of cardiomyopathy and we might even
be able to come up with some innovative therapies.
It’s a dominant autosomal inherited disease.
The electrocardiogram has a specific finding
that helps you to identify it, but usually,
the best way is with MRI where we can actually
see the fat replacing the right ventricular
muscle in arrhythmogenic cardiomyopathy.
Let me just give you some final hints about