Preventing Death in Heart
Patients
Rhythm problems and congestive
heart failure are two of the main end results of all
heart problems. The congestive heart failure in the
advanced stages carries a long term prognosis worse
than that of cancer. The rhythm problems involving
the lower chamber like ventricular tachycardia and
ventricular fibrillation can lead to sudden death.
A study called MADIT-II
involved patients who had very low ejection fraction
(ejection fraction is a measure of pumping power of
the heart muscles) due to blockages of heart
arteries. The study showed that a defibrillator
(also called ICD) can help prevent sudden death in
these patients. The defibrillator is sometimes
called shock box in every day lingo. A defibrillator
is like a pacemaker that is usually implanted under
the collar bone. The computer in this machine can
detect and try to treat any serious heart rhythm
problems that could potentially lead to death.
Another study called SCDHeFT
{pronounced as scud-heft (as in theft)} involved
persons who had weak heart muscles regardless of the
cause. In MADIT-II study above, the heart muscle
damage had to be from blocked heart arteries. The
study showed that these patients will benefit from
ICD as long as they got short of breath on every day
ordinary or less than ordinary activities (said to
be belonging to NYHA class 2 to 3 in scientific
lingo).
These two studies have made
millions of patients eligible for defibrillators.
Because of logistical as well as financial
constraints, there is a need for prioritization. A
recent study published in the journal Circulation
(Circulation. 2006; 114:135-142*) has studied the
cost-effectiveness of defibrillators in patients in
SCDHeFT study detailed above. If you care, SCDHeFT
stands for Sudden Cardiac Death in Heart Failure
Trial. The study shows that ICD is cost-effective in
patients that meet all of the following criteria:
- Have weak heart muscles
(ejection fraction down to ≤35%)
- Get short of breath on
ordinary activities
- Get defibrillator with
single chamber pacemaker
- Be expected to live more
than 8 years
My take on the study:
It is hard to try to put a
dollar figure on human life. When it comes to our
own loved ones, rationing the medical care can make
us angry. However, the limited numbers of dollars
available demand prioritization. Based on this
study:
- The ICDs are not
cost-effective in the patients that become short
of breath on less than ordinary activity or at
rest.
- We do know that patients
that have very weak heart muscles may also have
other problems that may seriously impair their
life span. According to this study, the ICD is
cost-effective if a person is expected to live
more than 8 years.
- The cost-effectiveness was
measured based on the cost associated with
single wire pacemaker. The trend lately has been
to implant two or even three wire pacemakers
with defibrillator. The calculation based on
much more expensive two or three lead
pacemakers will make these ICDs look much less
cost-effective
The development of
sophisticated ICDs is one of the major developments
in the field of cardiology. Offering an ICD based
purely on the basis of weakness of heart muscles is
a relatively new field. There is a need for
identifying the patients that ICDs may help the
most, so that we do not squander our resources by
the time we get to them.
*In case you are wondering,
this information with all the numbers can be used to
get to the original Circulation article.
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