January 20, 2000 Scientists at Johns Hopkins and Queen's
University in Ontario have shown that a small molecular glitch
is responsible for the sudden heart failure that almost
universally strikes after open heart surgery and that costs this
country an estimated $10 billion in post-operative medical care
every year. It's the first time scientists have demonstrated
that a problem at a molecular level can lead to any type of
acquired heart failure. Acquired heart failures are the common
ones, the researchers say, in contrast to those that are
inherited, far rarer forms of the disorder. In their study, the
scientists focused on molecules linked to heart muscle
contraction, in particular, an abnormal form of a protein called
troponin I (TnI), that's part of a heart muscle cell's
contractile "machinery," and that appears in certain patients
with weakened hearts. The work, reported in today's edition of
the journal Science, shows just how TnI goes awry and explains
how that leads to the heart failure known as "cardi