Treatments offer promise, sometimes a cure for arrhythmias
The heart has an internal electrical system that controls the rate and rhythm of heartbeats. When that electrical system goes awry, your heart can beat too quickly, too slowly or erratically.
This rhythm anomaly — called an arrhythmia — can range from a few skipped beats that are mostly just a nuisance to a racing heart that can lead to long-term damage.
Arrhythmias can be caused by a number of factors, including congenital heart problems, heart disease or other electric system dysfunctions in the heart, according to Kousik Krishnan, MD, an electrophysiologist (a cardiologist who specializes in heart rhythms) at Rush University Medical Center. There are many different types of arrhythmias that range in severity and occur in the different areas of the heart.
The most common type of arrhythmia is atrial fibrillation, a fast and irregular heart rhythm that can lead to blood clots, stroke and heart failure. An estimated 2.7 million Americans are living with atrial fibrillation, according to the American Heart Association. While your risk increases with age, other risk factors include heart disease and high blood pressure.
People with chronic conditions such as sleep apnea, diabetes and asthma have a higher risk of developing atrial fibrillation than people who do not have these conditions. While the direct cause for the connection between chronic conditions and atrial fibrillation is still unclear, some research suggests that inflammation associated with diabetes and reduced or obstructed airflow associated with sleep apnea and asthma may cause arrhythmia.
Another common arrhythmia is supraventricular tachycardia, an irregular heart rhythm that often occurs in younger people and causes the heart to race intermittently. "It can interfere with exercise and normal life because it can be a very uncomfortable rapid pulse that you feel in your chest," says Krishnan.
A high-tech cure
An arrhythmia can be diagnosed through an electrocardiogram (EKG), a test that records the electrical activity in the heart, or a home heart monitor that records heart activity in real time.
While some arrhythmias are treated with life-long medication, cardiac ablation can actually cure certain arrhythmias for good.
Ablation is an outpatient procedure in which the physician uses a catheter through a vein or artery in the leg to reach the heart and find the abnormal circuits causing the arrhythmia. Once the physician determines where the arrhythmia is coming from, he or she will cauterize (burn) and ablate (destroy) the tissue in the small area of the heart that is not performing properly. This solves the problem and cures the arrhythmia.
"Many of the arrhythmias we treat with ablation, such as supraventricular tachycardias, have success rates of 95 to 99 percent and complication rates below 1 percent," Krishnan says. "And it is very unlikely that the patient will develop another arrhythmia in the near future."
Unfortunately, if the arrhythmia was caused by heart disease, ablation will not cure the heart disease. "The underlying disease will still be there, but we are able to fix the electrical abnormality that is a consequence of the disease," Krishnan says.
Beating atrial fibrillation with ablation
Ten to 15 years ago, ablation was not used to treat atrial fibrillation; treatment was almost exclusively medication. Today, though, ablation is becoming a more widely used option for atrial fibrillation patients.
"In the past, atrial fibrillation has been very difficult to fix with ablation because the arrhythmia is not coming from just one circuit in the heart," says Krishnan. "There are hundreds of little circuits misfiring. It's like plugging a hole in a dike; you fix one area, but there is still a problem in another area."
Today, advanced medical technology, new techniques and plenty of research have opened up the possibilities for successfully treating atrial fibrillation with ablation. Krishnan and his colleagues at Rush are involved in research studies to determine the best strategies. These include the Sensei Robotic Catheter System, which integrates 3-D visualization with advanced control of catheters.
Using the robotic catheter system gives doctors more precise control of the catheter than they can get by hand by allowing them to move the catheter millimeter by millimeter in the heart to the exact place they want it to go. This enables the physicians to target abnormal tissue and avoid healthy tissue.
Younger, healthier patients have fairly high success rates — between 60 and 80 percent — for fixing atrial fibrillation thanks to the newer techniques; older patients with more advanced heart disease have a success rate of 50 percent.
This difference is due to the fact that older patients with more severe heart disease have more scar tissue in the atrium, making it more difficult to fix the atrial fibrillation completely. While it can be improved with ablation, it may not fully cure the arrhythmia as it does in younger patients whose heart disease has not progressed as much.
Other promising developments for treating atrial fibrillation are hybrid procedures, in which electrophysiologists and cardiac surgeons perform procedures together, in one setting.
"There's a huge benefit to these collaborations in treating atrial fibrillation," says Krishnan. "Some areas of the heart are easier for electrophysiologists to access by going through the vein or the artery. Other areas are very difficult for us to reach, but surgeons can easily reach them because they can get to crucial areas behind the heart that are more difficult to access from inside the heart. These are especially important in older patients with more advanced heart disease."
The state-of-the-art hybrid suites at Rush are designed to accommodate minimally invasive procedures involving both electrophysiologists and cardiac surgeons. These hybrid procedures represent a big area of research for the electrophysiology team at Rush.
"There have been many innovations in treating arrhythmias in the past few years and even more in development now," says Krishnan. "Through these advances, we can offer patients the best treatments and even a cure for arrhythmias."