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Recent
analysis of data from the MIRACLE (Multicenter InSync Ran-domized
Clinical Evaluation) study shows that cardiac resynchronization
therapy (CRT) reduces the need for hospitalization and may improve
survival, according to William T. Abraham, MD, from the University
of Kentucky, who reported the findings at a news conference on Monday.
This
is in addition to the therapys previously proven affects on
improving exercise endurance and enhancing wellbeing, Dr. Abraham
said. MIRACLE was the first large-scale, randomized, double-blind
control trial of CRT for heart failure.
In
looking at measures of heart failure hospitalization, the risk of
hospitalization for worsening heart failure was significantly reduced
by 50 percent, he said. CRT was also associated with
a significant reduction in hospital length of stay, with the average
length of stay for the control group seven days and for the group
receiving CRT 3.4 days.
Looking
at the total days of hospitalization for heart failure over six
months, it was reduced by 77 percent, Dr. Abraham reported. Other
measures of heart failure morbidity, such as worsening heart failure
requiring the use of IV medication, also showed significant reduction.
The
combined endpoint of death or worsening heart failure requiring
hospitalization was significantly reduced by 40 percent among those
receiving CRT, he said. From this analysis, we can conclude
that CRT reduces risk of heart failure hospitalization as well as
other measures of worsening heart failure.
However,
he noted, observed improvement in combined measures of heart failure
morbidity and all-cause mortality awaits confirmation by ongoing,
large-scale morbidity and mortality trials.
There
was no significant difference between CRT and no CRT in terms of
effect on mortality, Dr. Abraham said, explaining that the
study group was too small to assess mortality.
Dr.
Abraham also reported on a small study from the University of Florence
in Italy, conducted by Dr. Luigi Padeletti and colleagues, that
observed the effects of CRT on cardiac structure, function, and
neurohormones. Researchers found a significant correlation between
reduction in tumor necrosis factor-a and improvement in the volume
of blood the heart was able to pump with each contraction, as well
as in quality of life.
CRT
was shown to improve patient outcomes and appears to reverse some
of the adverse effects of heart failure related to structural changes
and augmentation of the cytokine systems, he said.
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