October 12, 2007
Freezing Hearts Back into Rhythm
Genesis first in nation to perform new FDA-approved procedure for atrial flutter
DAVENPORT, IOWA - Imagine feeling like you’re running a race 24 hours a day or like you’re on a treadmill and can’t get off.
A 57-year-old patient, who has a heart rhythm disorder called atrial flutter, knows that constant, heart-racing feeling. At times, the upper chambers of his heart would race twice as fast – around 300 times a minute – than the lower chambers. Episodes would come and go unexpectedly. He experienced palpitations and shortness of breath. He couldn’t sleep well. He felt too tired to exercise.
“I was tired when I went to bed, and I was tired when I got up,” the patient says. “My doctor told me it was because it was like running a marathon 24-7. I used to be a runner, but never felt that tired.”
This week, electrophysiologist Michael Giudici, M.D., used a “cool” catheter in hopes of slowing his patient’s irregular heartbeat in a first-in-the-nation procedure at Genesis Medical Center, Davenport.
Using a cardiac cryoablation system, he froze the abnormal heart tissue that was disrupting the heart’s electrical activity.
For the past two years, Genesis has been one of 10 study sites in the nation testing a device by CryoCor of California that uses a cold-tip cardiac catheter snaked through the veins to deep-freeze the heart tissue causing the electrical short circuit.
The device uses extremely cold temperatures to block conduction of abnormal electrical signals without damaging the surrounding tissue, and helps restore the heart to its regular rhythm.
The catheter has a small tip that is repeatedly applied to the tissue until the full suspect area is treated. “The catheter, within a very short period of time, gets to –90 degrees C,” Dr. Giudici says. “That’s cold. We call the machine Mr. Freeze.”
First-in-the-nation
In August, CryoCor received FDA approval to use its system to treat atrial flutter. The company confirmed that Dr. Giudici is the first to do the procedure outside of a clinical trial.
“A first-in-the-nation heart procedure at Genesis Medical Center, Davenport isn’t that unusual anymore,” Dr. Giudici says. “Genesis is a leading center for the study of heart failure devices and arrhythmia-device research. In the next few months, we will be one of 10 centers in the world to study a new laser balloon catheter to treat intermittent atrial fibrillation. And soon, I will be training on a new system for chronic atrial fibrillation.”
During the clinical trial, about 25 Genesis patients got a head start on the rest of the nation and benefited from the cardiac cryoablation procedure. “We’ve cured people of a very debilitating problem, and that’s very gratifying to see,” he said. “The complication rate for cryoablation at this institution has been close to zero.”
More than 200,000 Americans have atrial flutter, where the upper chambers of the heart beat too quickly but in a well-defined rhythm. Far more, 2.3 million Americans have atrial fibrillation, where the upper chambers quiver in an irregular rhythm. The FDA has yet to approve freezing technology for atrial fibrillation.
For some patients, medication or pacemakers are effective. In the mid-‘80s, cardiac defibrillators were invented. Then in the ‘90s came catheter ablation, which uses radiofrequency to burn, or cauterize, the tissue areas that are generating the irregular heartbeat. Radiofrequency for atrial fibrillation has been available at Genesis Medical Center since 2004.
“With the advent of cryoablation, we go into the heart and take the temperature down extremely quickly in seconds to freeze the tissue (the source of the rhythm disturbances),” he says.
When the procedure began, the patient’s heart was beating at 144 beats per minute. After a couple of hours of cryoablation, it had fallen to 126 beats per minute, and the orange squiggly lines on the monitor that indicated abnormal electrical signals in the heart were far calmer.
Freezing the flutter
The patient has tried medication and radiofrequency ablation procedures to cure the problem, to no avail. His case was particularly challenging. “We got his flutter to slow a great deal, which we couldn’t do with radiofrequency energy, and then we cardioverted him. We’ll have to see if he has any reoccurences over time,” Dr. Giudici says.
He likened cryoablation to the unforgettable scene in the 1983 movie “A Christmas Story,” where little Ralphie Parker gets his tongue stuck to a flagpole.
“Cryoablation is like the worst ‘Christmas Story’ flagpole ever,” Dr. Giudici says. “The catheter sticks immediately to that tissue; delivers a pulse of cryoenergy; and, does a nice job of eliminating the rhythm problem without harming the tissue.
“When I do radiofrequency ablation, we may do 110-175 burns inside the heart whereas during cryoabation, it’s only 30 to 40. You affect more tissue with a single lesion. It penetrates deeper into the tissue, so we hope we’re getting a more complete change and not going to see reoccurrences. Cryoablation also is not painful.”
A disadvantage of the hot-tip catheter is it creates burns, or scars. “Cryoablation is kind of the neutron bomb of cardiology,” Dr. Giudici says. “You injure the contents of the cell, but leave the structure of it intact — like dropping a bomb that leaves all the buildings intact but not everything inside. It doesn’t change the architecture of the heart.”
Several days after the procedure, the patient says he feels better already. “I know my heart rate was approximately 140 beats per minute before the procedure. At this point, my heart rate is much slower, and I’m hoping it stays that way.”
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