Intermountain Medical Center reseachers develop new 3-D technology to treat atrial fibrillation
Researchers at the Intermountain Heart Institute at Intermountain Medical Center have developed a new 3-D technology that for the first time allows cardiologists the ability to see the precise source of atrial fibrillation in the heart – a breakthrough for a condition that affects nearly three million Americans.
This new technology that maps the electronic signals of the heart three dimensionally significantly improves the chances of successfully eliminating the heart rhythm disorder with a catheter ablation procedure, according to a new study presented at the Heart Rhythm Society’s National Scientific Sessions in Denver on Saturday, May 11, 2013.
Atrial fibrillation occurs when electronic signals misfire in the heart, causing an irregular, and often chaotic, heartbeat in the upper left atrium of the heart.
Symptoms of atrial fibrillation include irregular or rapid heartbeat, palpitations, lightheadedness, extreme fatigue, shortness of breath or chest pain. However, not all people with atrial fibrillation experience symptoms.
“Historically, more advanced forms of atrial fibrillation were treated by arbitrarily creating scar tissue in the upper chambers of the heart in hopes of channeling these chaotic electrical signals that were causing atrial fibrillation,” said researcher John Day, MD, director of the heart rhythm specialists at the Intermountain Heart Institute at Intermountain Medical Center. “The beauty of this new technology is that it allows us for the first time to actually see three dimensionally the source of these chaotic electrical signals in the heart causing atrial fibrillation.”
Previously, cardiologists were able to map the heart in 3-D to enhance navigation of catheters, but this is the first time that they’ve utilized 3-D imaging technology to map the heart’s specific electronic signals. Armed with this information, cardiologists can now pinpoint exactly where the misfiring signals are coming from and then “zap” or ablate that specific area in the heart and dramatically improve success rates.
With this new technology, cardiologists will now be able to treat thousands of more patients who suffer from advanced forms of atrial fibrillation and were previously not felt to be good candidates for this procedure.
“The capabilities of the new technology can be compared to a symphony concert,” said Jared Bunch, MD, medical director for electrophysiology research at the Intermountain Heart Institute at Intermountain Medical Center. “During the concert, you have many different instruments all playing different parts, much like the heart has many frequencies that drive the heartbeat. This novel technology allows us to pinpoint the melody of an individual instrument, display it on a 3-D map and direct the ablation process.”
Treatment for atrial fibrillation (AF) depends on how severe or frequent the symptoms are and whether you already have heart disease. General treatment options include medicines, medical procedures, and lifestyle changes.
Treatment of AF is designed to:
Prevent blood clots from forming, and thereby reduce the risk for stroke.
Control how many times a minute the ventricles contract. This is called rate control. Rate control is important because it allows the ventricles enough time to completely fill with blood. With this approach, the irregular heart rhythm continues, but the person feels better and has fewer symptoms.
Restore the heart to a normal rhythm. This is called rhythm control. Rhythm control allows the atria and ventricles to work together again to efficiently pump blood to the body.
Treat any underlying disorder that’s causing or raising the risk of AF-for example, hyperthyroidism.
Who Needs Treatment for Atrial Fibrillation?
People with no symptoms and no related heart problems may not need treatment. AF may even go back to a permanent normal heart rhythm on its own. In some people who have AF for the first time, doctors may choose to use an electrical procedure or medicine to restore the heart rhythm to normal.
Repeated episodes of AF tend to cause changes to the electrical system of the heart, leading to persistent or permanent AF. Most people with persistent or permanent AF need treatment to control their heart rate and prevent complications.
The research team used the new 3-D mapping technology on 49 patients between 2012 and 2013 and compared them with nearly 200 patients with similar conditions who received conventional treatment during that same time period.
About one year after catheter ablation, nearly 79% of patients who had the 3-D procedure were free of their atrial fibrillation, compared to only 47.4% of patients who underwent a standard ablation procedure alone without the 3-D method.
“This new technology allows us to find the needles in the haystack, and as we ablate these areas we typically see termination or slowing of atrial fibrillation in our patients,” says Dr. Day.
Rhythm Control - Atrial Fibrillation
Restoring and maintaining a normal heart rhythm is a treatment approach recommended for people who aren’t doing well with rate control treatment. This treatment also may be used for people who have only recently started having AF. The long-term benefits of rhythm control have not been proven conclusively yet.
Doctors use medicines or procedures to control the heart’s rhythm. Patients often begin rhythm control treatment in a hospital so that their hearts can be closely watched.
The longer you have AF, the less likely it is that doctors can restore a normal heart rhythm. This is especially true for people who have had AF for 6 months or more.
Restoring a normal rhythm also becomes less likely if the atria are enlarged or if any underlying heart disease worsens. In these cases, the chance that AF will recur is high, even if you’re taking medicine to help convert AF to a normal rhythm.
Medicines. Medicines used to control the heart rhythm include amiodarone, sotalol, flecainide, propafenone, dofetilide, and ibutilide. Sometimes older medicines—such as quinidine, procainamide, and disopyramide—are used.
Your doctor will carefully tailor the dose and type of medicines he or she prescribes to treat your AF. This is because medicines used to treat AF can cause a different kind of arrhythmia.
These medicines also can harm people who have underlying diseases of the heart or other organs. This is especially true for patients who have an unusual heart rhythm problem called Wolff-Parkinson-White syndrome.
Your doctor may start you on a small dose of medicine and then gradually increase the dose until your symptoms are controlled. Medicines used for rhythm control can be given regularly by injection at a doctor’s office, clinic, or hospital. Or, you may routinely take pills to try to control AF or prevent repeat episodes.
If your doctor knows how you’ll react to a medicine, a specific dose may be prescribed for you to take on an as-needed basis if you have an episode of AF.
Procedures. Doctors use several procedures to restore a normal heart rhythm. For example, they may use electrical cardioversion to treat a fast or irregular heartbeat. For this procedure, low-energy shocks are given to your heart to trigger a normal rhythm. You’re temporarily put to sleep before you receive the shocks.
Electrical cardioversion isn’t the same as the emergency heart shocking procedure often seen on TV programs. It’s planned in advance and done under carefully controlled conditions.
Before doing electrical cardioversion, your doctor may recommend transesophageal echocardiography (TEE). This test can rule out the presence of blood clots in the atria. If clots are present, you may need to take blood-thinning medicines before the procedure. These medicines can help get rid of the clots.
All of the patients in the study had failed medications and 37 percent had received prior catheter ablations. The average age of study participants was 65.5 years old and 94 percent had persistent/chronic atrial fibrillation.
Previous research has shown that the incidence of atrial fibrillation increases with age. A report from the American Heart Association shows the median age for patients with atrial fibrillation is 66.8 years for men and 74.6 years for women.
If untreated, atrial fibrillation can lead to blood clots, stroke and heart failure. In fact, people with atrial fibrillation are five times more likely to have a stroke than people without the condition.
Intermountain Medical Center is the flagship facility for the renown Intermountain Healthcare system.
###
Jason Carlton
.(JavaScript must be enabled to view this email address)
801-507-7454
Intermountain Medical Center