June 23, 2010
Dear Friend of the Texas Heart Institute,
On the case at THI–a real-life mystery story . . . Almost everyone enjoys a good mystery story. Especially the kind of tale in which a crafty detective helps piece all the clues together and outsmarts the villain. Bad things are brought to an end; the world is made a little safer. In the world of heart disease, we encounter mystery stories all the time. And, I am proud to say, we've got some skilled detectives here at the Texas Heart Institute at St. Luke's Episcopal Hospital (THI at St. Luke's).
There is one particularly tough case we're getting closer to cracking right now. Our villain is the worst kind, preying on people when they are at their most vulnerable–following heart surgery.
It is atrial fibrillation, aka A-Fib, the most common cardiac arrhythmia (abnormal heart rhythm).
Just like a mystery novel thug, A-Fib is a mean piece of work. It can result in fainting, chest pains or, worse, congestive heart failure. It can even lead to stroke. A-Fib is the most common adverse effect patients have following heart surgery. Up to 40 percent of patients who undergo coronary artery bypass surgery fall victim to A-Fib.
Because there are thousands of such surgeries each year, thousands of potential new victims need our help. That's a lot of human suffering, especially for patients who have already been through so much by the time they get to surgery. But, the A-Fib story gets worse. Patients stricken by A-Fib need additional medications and have longer hospital stays. Put it all together and it's a drain on precious health-care resources.
So, the stakes are high—for those many surgery patients, and for all of us.
THI's top "detective" on the case is Dr. C. David Collard, Chief of Cardiovascular Anesthesiology. He and his investigative team have already pieced together quite a case on post-operative A-Fib.
Our research has uncovered genetic predictors of A-Fib. Investigators have identified a number of polymorphisms, or genetic variants, on something called "chromosome 4q25." These variants have been identified as being associated with A-Fib. In other words, when they are around after surgery, A-Fib might not be far behind. It means these variants can be predictors or precursors of A-Fib.
Dr. Collard has collaborated with Simon Body from the Department of Anesthesiology at Brigham and Women's Hospital, Harvard Medical School, and the Vanderbilt University School of Medicine. Almost 2,500 patients at Brigham and Women's Hospital and at THI at St. Luke's have been studied for 45 polymorphisms in "4q25." Seven of those variants were identified as predictors of A-Fib after surgery.
That means we have a way to predict which patients might be the next victim of postoperative A-Fib—some already impressive detective work by our dedicated scientist-sleuths.
But the mystery lingers. We don't quite know enough about the biological process that leads to so many cases of A-Fib after surgery. We haven't yet figured out exactly by what chain of events those genetic variants got into our patients in the first place. However, using data already collected, and employing other "detective" methods, we're getting closer to unraveling this mysterious process. When we do, we believe we'll be in a far better position to prevent A-Fib in surgery patients, or at least to lessen the consequences.
"Our investigation has laid the genetic groundwork for deciphering the biological mechanisms of postoperative A-Fib," says Dr. Collard. "The next step we expect will be developing therapeutic and preventative strategies for patients at risk."
Bad things will be brought to an end. The world will be a little safer. I can't say precisely when we'll solve this scientific who-done-it, one of many such mysteries on which committed THI scientist-physicians are hard at work. But I can say we are determined to outsmart the villain. We've already come a long way because we've got our best detectives on the case!
Respectfully,
James T. Willerson, MD
President and Medical Director
Contact Dr. Willerson
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