Radiofrequency ablation has been used for more than 10 years to treat various heart problems, but only recently has it been used to stop A-fib, says Macy C. Smith, Jr., MD, FACC, an electrophysiologist with Cardiovascular Associates in Birmingham.
Up until about two years ago, physicians were much more likely to treat Afib with medications and cardioversion. “Because medicines can have serious side effects, not all patients can tolerate them. That makes cardioversion a next step, but while it can convert the heart to a regular sinus rhythm, it has a low success rate in keeping it there,” Smith says. “In the past couple of years, we have been able to perfect the radiofrequency ablation technique to make it a safe and effective treatment option for atrial fibrillation.”
In Afib, the heartbeat is irregular and rapid due to disorganized signals from the heart’s electrical system. The upper chamber of the heart may beat as often as 300 times a minute, about four times faster than normal. There are four pulmonary veins in the left atrium that can become electrically active. “When that occurs, the electricity can bombard the left atrium and cause irregular heart rhythm,” Smith points out. “Past experience tells me to start with those veins when making a diagnosis. However it is possible that the entire left atrium can be diseased. Radiofrequency ablation can cure most of these types of cases.”
The electrophysiologist performs the minimally invasive, closed-chest procedure using thin, flexible catheters that are inserted into small punctures in the groin, arm or neck area and threaded to the heart. Small electrodes on the tip of the catheters stimulate and record the heart’s activity. This test, called an electrophysiology study (EPS), allows the doctor to pinpoint the exact location of the short circuit. Once the location is confirmed, the short circuit is either destroyed to reopen the electrical pathway, or blocked to prevent it from sending faulty signals to the rest of the heart. This is done by sending energy through the catheters to destroy a small amount of tissue at the site. The energy may be either hot (radiofrequency energy), which cauterizes the tissue, or extremely cold, which freezes or “cryoablates” it.
While radiofrequency ablation offers a cure for Afib patients, it is not 100 percent effective in all patients. “It is most successful in treating paroxysmal atrial fibrillation with a cure rate of 75 to 80 percent in these patients when we isolate the pulmonary veins,” Smith says. “If the Afib is more persistent or permanent, the ablation doesn’t work as well. Further studies are under way, however, and progress is being made in those areas as well.”
As with most medical procedures, radiofrequency ablation does have risks that include blood clots, strokes, blockage or perforation of the pulmonary veins or heart. Improvements in catheter ablation tools and technologies have helped decrease these risks to patients. But without a procedure to control the Afib, the condition itself can lead to other rhythm problems, feeling tired all the time, and heart failure which causes symptoms such as filling up with fluid, swelling in hands, legs and feet, and shortness of breath. People with Afib are five times more likely to have a stroke compared to people without the condition.
As the population of the United States and other countries ages, the prevalence of Afib is projected to more than double to 5.6 million adults in the next 40 years. Early diagnosis and treatment of Afib is important. “Identifying the condition early and staying on top of it is beneficial to patients, because it is harder to cure if a patient has been in Afib for years. We don’t have to jump straight to ablation for these patients, but we do need to monitor and keep a check on the condition,” Smith says. “Because radiofrequency ablation is available, we now know we can offer the possibility of a cure to most who suffer from this debilitating condition.”