December 8, 2004
Starkweather, B.S. and Asher Kimchi M.D.
Frankfurt, Germany –
Prophylactic use of implantable cardioverter-defibrillators in
patients who have recently had an acute myocardial infarction
was shown to not significantly reduce overall mortality. The
results of the Defibrillator in Acute Myocardial Infarction
Trial were published by Stefan H. Hohnloser, M.D., et. al,
from J.W. Goethe University in Frankfurt, Germany, in the
December 9, 2004 issue of the New England Journal of Medicine.
While ICD therapy was associated with a reduction in the rate
of death due to arrhythmia, this benefit was offset by an
increase in mortality from nonarrhythmic causes.
The first 6 to 12 months after
myocardial infarction constitute a period during which there
is a particularly high risk of death from arrhythmia, and few
therapies have been effective in counteracting this risk. This
study evaluated the possible benefit of prophylactic use of
ICDs in this patient population.
Patients aged 18 to
80 years were eligible for the study if they had recently had
a myocardial infarction (6 to 40 days ago) and had a left
ventricular ejection fraction of 0.35 or less. The also had to
have a standard deviation of normal to normal RR intervals of
70msec or less or a mean heart rate of at least 80 bpm over a
24 hour period.
randomly assigned in a 1:1 ratio to either receive
implantation of an ICD or not. All patients received the best
standard medical therapy, including ACE inhibitors, beta
blockers, aspirin, and lipid lowering drugs, as appropriate.
Patients in the ICD group underwent implantation within one
week of randomization.
followed for a maximum of 4 years, with the study taking place
from April 1998 to September 2003. The primary outcome was
death from any cause, with a secondary outcome being death
from cardiac arrhythmia.
During an average
observation period of 30 +/- 13 months, 120 patients died, 62
in the ICD group and 58 in the control group (95 confidence
interval, 0.76 to 1.55, two sided P=0.66). Death from
arrhythmic causes was significantly lower in the treatment
group, with an annual rate of 1.5 percent in the ICD group and
3.5 percent in the control group (95 percent confidence
interval, 0.22 to 0.83, two-sided P=0.009). However, the death
rate from cardiac, nonarrhythmic causes was significantly
increased in the ICD group (P=0.05).
These results show a
statistically significant reduction (by more than 50 percent)
in the risk of death due to arrhythmia in the ICD group;
however, this effect was offset by a significant increase, of
similar magnitude, in the rate of death from nonarrhythmic
causes. The most likely explanation for this data is that
patients “saved” from an arrhythmia related death by ICD
therapy are also at high risk for death from other cardiac
However, the present
data does not prove that ICDs reduce mortality post-acute
myocardial infarction, despite the fact that they may decrease
the risk of death from cardiac arrhythmia.
Coauthors: Karl Heinz
Kuck, M.D.; Paul Dorian, M.D.; Robin S. Roberts, M.Tech.; John
R. Hampton, M.D., Robert Hatala, M.D.; Eric Fain, M.D.;
Michael Gent, D.Sc., and Stuart J. Connolly, M.D.