"Questions and Answers with Stuart Berger, M.D."
Topic: Sudden Cardiac Death
Written by:
Stuart Berger, M.D.
Associate Professor of Pediatrics
Medical College of Wisconsin
Medical Director, The Heart Center
Children's Hospital of Wisconsin
U.S. |
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Edited by: Mona Barmash
Posted: May 20, 2000
Q. What is Sudden
Cardiac Death?
A.
Sudden cardiac
death (SCD) is an unexpected, sudden cardiac event that leads to
death. It is most likely to occur in a patient with an
underlying cardiac abnormality, whether known or not, and is usually
caused by an abnormal heart rhythm (arrhythmia).
Q.
I always had the impression that sudden death was not a
problem for CHD patients. Was I deluding myself?
A. It is actually very unusual for this to be a problem. In
this day and age with early repair, the heart is in better "shape"
and suffers less from some of the things that are known to
predispose people to arrhythmias. In addition, most of the
conditions that predispose children to SCD are very rare.
Q.
Which cardiac conditions are considered to be at-risk for SCD?
A. The general list includes: Cardiomyopathy, coronary
artery abnormalities, Long QT Syndrome, ARVD (Arrhythmogenic Right
Ventricular Dysplasia), Wolff-Parkinson-White Syndrome, myocarditis.
Patients with Pulmonary Hypertension (Eisenmenger�s Syndrome) are
also at risk.
Tetralogy patients
with less than good repairs, with a lot of pulmonary valve leakage
and prolonged RV (right ventricle) conduction delay are at risk of
sudden death due to arrhythmias (Ventricular Tachycardia).
Q.
Can uncontrolled arrhythmias lead to SCD?
A. They can, but it typically depends upon the type of
arrhythmia, the ventricular function, as well as the underlying
condition. I would say that nowadays, the majority of rhythm
disturbances can be treated successfully to prevent SCD in the
patient at risk.
Q.
Is SCD more common for patients who have problems with their
hearts (such as enlargement or scar tissue from previous surgery)?
A. Generally speaking, SCD occurs only in those who have an
underlying cardiac condition. The problem is that some patients
never have signs or symptoms, and their first presentation may be
with SCD.
Q.
What about in adult patients?
A. I think the same holds true. As long as the repair and
ventricular function are good, and there are no arrhythmias, the
risk of SCD is low. There are indeed some types of repairs that are
associated with late arrhythmias, but most are controllable.
These include patients who have had atrial switch operations
(Mustard or Senning) and/or any patient with
underlying cardiac
dysfunction.
Q.
Are children/adults with repairs that don't fully fix a
heart, like HLHS/Fontans, at higher risk for SCD? Is this why they
have to do annual holters and have stress tests?
A. In general
children with fontan, regardless of what the original defect was are
at risk for arrhythmias, and that is certainly why holters and ecgs
are monitored closely in this group of patients. I think it is
conceivable that if ventricular function is poor the arrhythmias may
be more common.
Q. Can prolonged heat exposure or prolonged activity result
in SCD, even when the child has a high O2 sat?
A. I am not aware of that being a problem.
One should use general good judgment.
If the parent is uncomfortable in the heat and humidity, more
likely than not so will the child.
Adults with CHD
Q.
Is SCD a problem for ACHD'ers who were repaired later in life?
A. Generally not, although it depends on the specific
defect(s) and on the "condition" of the heart.
Please see the above for situations in which SCD may be a risk.
Q.
Should adult CHD patients routinely wear holter monitors
to check for undetected arrhythmias?
A. Again, I think it depends on the specific repair that the
patient has had. Most repairs are done successfully and the risk of
arrhythmias is low. However, in some repaired defects, as discussed
above, the risk may be higher. Those are the patients that may need
to be watched more closely.
Q.
In your experience in adult patients with complex congenital heart
disease, is there a certain type of arrhythmia that is associated
with SCD?
A. Usually, either ventricular arrhythmias and/or atrial
tachycardias with rapid conduction of impulses to the ventricles
can be associated with SCD
Screening for Congenital Heart Defects and Arrhythmias
Q.
How can we get our PC's to do echoes and EKG's on siblings of CHD
kids, even if they don't have any symptoms? I know that it is costly
but I'm willing to pay
A. This is a very difficult question. I think that the best
thing to do is to talk with them and let them know of your concerns.
Usually significant CHD can be ruled out by physical exam, but some
things that may occur in families (such as Hypertrophic
Cardiomyopathy, Long Q-T Syndrome, ARVD, etc.) may warrant further
studies, so it does depend on the specific condition that you are
trying to rule out.
Many of the other conditions present with symptoms and/or findings
on physical examination that would appropriately guide further
studies.
Q.
If there were mandatory echoes or screening for cardiac conditions,
could some of these SCD's be prevented in children? I just wonder if
it couldn't help since most of this is asymptomatic. Can we
potentially catch it when they are babies, or young toddlers?
A. I think that some but not all of the conditions could be
ruled out with echoes. Some children would also require serial
echoes in order to pick up some of these things.
Q.
Do you think it is reasonable to have siblings of CHD children
evaluated for cardiac problems even if they show no symptoms?
A. It depends
upon the defect being screened for.
Q.
For which defects would you suggest
that siblings be screened?
A. The defects that are familial should certainly be
screened. Typically left heart obstructive lesions (such as aortic
stenosis), hypertrophic cardiomyopathy (HCM), some forms of dilated
cardiomyopathy, ARVD, LQTS, etc., are considered to be
"familial").
I think that in many of the other cases, if there are no symptoms
and no abnormalities on physical exam, they may not need to have
further testing.
Activity Level and Restrictions for children/adults with CHD
Q.
Many of us parents are told not to let our kids "push" themselves
with physical activities - is it because of the possibility of SCD?
A. Well it's not very common at all, but there have been
many such cases throughout the country recently. Generally, patients
who have known congenital heart diseases
that have been associated with activity related SCD should
have their activity restricted.
This includes Hypertrophic Cardiomyopathy, LQTS, Dilated
Cardiomyopathy, Marfan syndrome, etc.
Q.
What precautions, if any, should a parent/patient take?
A. Exercise should be limited in patients at risk, as
discussed above.
In patients that are not at
risk of SCD, there are not specific precautions that are necessary
other than being allowed to rest when feeling tired.
Long QT Syndrome
Q.
What is the incidence of SCD in patients with Long QT Syndrome?
A. It is
relatively high if untreated, but we are learning that are several
genetic subtypes of LQTS, and each one may have a little different
risk than the other subtype.
Q.
What are the sub-types?
A. I am honestly not
sure that all of the subtypes have been worked out genetically yet.
Jervell Lange Nielsen is one of the familial types of LQTS, and
certainly, SCD risk associated with this is high if untreated.
Arrhythmias
Q.
Is it true that you can see an arrhythmia develop after stress, when
the body is "cooling down"?
A. I'm not sure that the "cooling down" process can cause
arrhythmias. More likely it is entirely related to ventricular
function and/or patients that have the anatomy and physiology known
to be associated with arrhythmias.
Comment:
But I know with LQTS that the syncope (fainting) can occur after the
exercise, so it must be somehow related.
A. LQTS is a condition in which the arrhythmia is thought to
be catecholamine driven, that is, it is thought to be associated
with exercise, fright, etc. There is no doubt that exercise can make
someone prone to arrhythmias and SCD in patients that have an
underlying condition that puts them at risk.
Blood Clots
Q.
How often have you heard of a CHD child dying suddenly due to a
blood clot? In particular, kids with HLHS that are pre-fontan. Also,
what's the general feeling on putting these kids on aspirin or blood
thinners? How effective is aspirin?
A. I can't say that SCD due to a clot in a patient with CHD
is very common. Many centers place children on aspirin or coumadin,
but the practice is not uniform.
Studies are underway to answer
this question.
Promoting
Awareness of Sudden Cardiac Death
Q. I
have started a support group, and I'm trying to raise awareness
about SCD. When speaking to teachers, what should we tell them,
other than obviously listen to the kids?
A. I think it's
very important that
teachers, coaches, etc., be trained in CPR. We are also in the midst
of a project in Wisconsin to try and get AED's (automatic external
defibrillators) into all of the high schools.
Q.
Is there anyway to treat these kids
while it's happening
before it's too late?
If a child were to collapse, is there something that can be done
before they stop breathing... are declared dead?
A. The only therapy that we know of is CPR and
defibrillation.
Q.
What are the symptoms to be watchful for?
A. Fainting during exercise, chest pain with exertion,
shortness of breath, palpitations, and syncope (fainting) in
general.
Q.
What can be done about kids that are experiencing SCD on the
playground without any prior symptoms?
A. Know what one can do for intervention! There are some
children who will present with SCD without ever having symptoms.
A subset of these children may not be detected with
screening. Therefore, know how to do CPR and
how to activate the EMS system.
Typically this involves being sure that one knows how to
activate the local 911system.
We are trying to
emphasize the importance of screening, including detailed history
and family history. Although many children have no symptoms, some
may actually have symptoms that they are denying. That is why
symptom awareness is
critical. Lastly, we feel that it is important for people in the
school to be well versed in CPR, and to have access to
defibrillators. Though this is certainly controversial, we feel that
it has the potential to save the lives of children and adults.
This article was reviewed prior to publication by:
Richard Donner, M.D.
Adult Congenital Heart Program
The Children's Hospital of Philadelphia
William Moskowitz, M.D.
Director of Pediatric Cardiac Catheterization Laboratory
Director of Pediatric Heart / Lung Transplantation
Virginia Commonwealth University
Medical College of Virginia
Richmond, VA
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