Dr. Cox's new maze

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Posted by Jeanne on February 24, 2004 at 15:50:26:

I found this intesting, it came from Boston.com. I hope you won't find it too long.


Home > Your Life > Health & Fitness > Diseases & Treatments

Off beat
Treatment options expanding for heart condition that leads to many strokes
By Michael Lasalandra, Globe Correspondent, 2/24/2004

After waking up in the middle of the night, his heart pounding out of control, Kermit Birchfield, 64, was told he'd have to take medications for the rest of his life.

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But the drugs that kept his heartbeat regular left him feeling totally run down.

"I'm a marathon runner and I couldn't exercise," he said. "I was miserable."

Birchfield, like nearly 5 percent of people over 60 and 10 percent of those over 80, has atrial fibrillation, episodes of irregular heartbeats caused by faulty electrical signals in the heart. The symptoms of atrial fibrillation include shortness of breath, chest discomfort, fatigue, light-headedness and anxiety, and if left uncontrolled, the condition could lead to a debilitating or fatal blood clot or stroke.

The number of patients with atrial fibrillation is skyrocketing as baby boomers age and more people with heart trouble survive long enough to have secondary problems. A British study released this month said spending there on the disorder nearly doubled between 1995 and 2000.

The growth in patients -- and frequent complaints about the medications used to thin blood and control arrhythmia -- have fueled the search for better treatments. Now, there are so many in development that heart specialists can't agree on which is best.

"If you ask 10 different cardiologists, you'll get 20 different opinions," said Dr. Bruce Stambler, director of clinical electrophysiology and pacing at University Hospitals of Cleveland and Case Western Reserve University.

"The field is undergoing an evolution," he said. "It's an exciting time."

The advances break down into two categories -- medications with fewer side effects, and interventions, including surgery, that are becoming less and less invasive.

Just what causes the electrical abnormality in the first place is unknown, but drug therapy remains the first choice for most patients. Beta blockers and calcium channel blockers, which work to slow the heart rate and therefore the severity of symptoms, are usually the first choice, followed by anti-arrhythmic drugs, such as propafenon or flecainide, which help reduce the frequency of episodes.

All patients must take blood-thinners such as warfarin to prevent blood from stagnating in the upper chambers of the heart and forming clots that can lead to strokes. (One-quarter of all strokes sustained by those over 65 are attributed to atrial fibrillation.)

Some of these drugs can cause side effects that are difficult to live with, including fatigue, loss of libido and bleeding.

"Many patients have a horrible quality of life," said Dr. Douglas L. Packer of the Mayo Clinic. "That's why we do most of these procedures."

Several drugs are showing promise for treating atrial fibrillation without those side effects, or the need for invasive procedures. Blood pressure drugs known as ARBs, or angiotensin receptor blockers, have fewer side effects, but their efficacy against atrial fibrillation is still unproven, said Dr. Jeremy Ruskin, director of the cardiac arrhythmia service at Massachusetts General Hospital. Ximelagatran, a new anticoagulant nearing federal approval is said to be easier to take than blood thinners like warfarin because it requires less monitoring.

For those who can't handle the side effects of medications or have other problems, there are three basic options to regulate the heartbeat -- catheter ablations, surgery, or the implantation of pacemakers or defibrillators. Catheter ablation is aimed at damaging small pieces of heart tissue to eliminate the abnormal impulses. The catheter is snaked through the groin to the heart in a minimally invasive procedure, with no surgery required.

The most common ablation technique calls for delivering a high-frequency, low-voltage current to the site and basically burning the tissue. This process, known as radiofrequency ablation, carries about a 1 percent chance of causing a blood clot that can lead to a stroke and damage the pulmonary vein. The cure rate is only 50 percent after the first procedure, but rises to 80 percent after the second, although long-term data is lacking.

Birchfield said the six-hour procedure, performed under light sedation, was virtually painless.

"It seems to have done the trick for me," said Birchfield, who had the operation at Mass. General last June. "I'm back running again. I'm signed up for the New York Marathon in November."

This month, Ruskin pioneered a new technique, called cryoablation, to freeze the tissue instead of burning it.

"We're hoping that cryoablation may be even less likely to cause a stroke, and may pose less risk to the [pulmonary] vein," said Ruskin, who also performed Birchfield's ablation. It will be another six to eight weeks before doctors know whether the procedure worked in the first patient.

Doctors elsewhere also are trying microwave technology and ultrasound as energy sources to create lesions and disrupt the electrical impulses.

Dr. James L. Cox, a heart surgeon at the Washington University School of Medicine in St. Louis, is now fine-tuning a minimally-invasive version of an operation he developed that involves cutting maze-like patterns in the atrium to disrupt abnormal electrical patterns. Until recently, surgery was done only as an open-heart operation in combination with bypass or mitral-valve-replacement surgery, but Cox said his latest techniques make surgery roughly as invasive as ablation.

"It adds two minutes to a mitral-valve surgery," he said. "As a stand-alone procedure, it can be done in an hour, through a little incision."

Implantable pacemakers and defibrillators, commonly used to pace slow or shock fast heartbeats, are also being tried in certain circumstances to treat atrial fibrillation.

"We know there's no one simple solution," said David Adinalfi, an official with St. Jude Medical, a Minnesota device-maker working on both technologies.

Scott Niles of Peterborough, N.H., said he had seen his symptoms, including shortness of breath and nausea, get worse over the course of several years until he couldn't live with it any longer. The antiarrhythmics made him too lethargic to ride his bicycle.

"I probably do 70 or 80 miles a week," said the 65-year-old developer of computer systems. "I'm an endorphin junkie."

So, he had a radio-frequency ablation in June 2000 and another one six months later. Except for a brief series of episodes last fall, he has been symptom-free since the second surgery, and he hopes he can avoid a third.

"I haven't had any problems with atrial fibrillation" in three years, he said. "But I'm always afraid it's going to happen again. Sometimes I wake up in a cold sweat, from fear."


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