Electrophysiology (or EP) is the name of the branch of cardiology that deals with heart rhythm disorders. Catheter ablations are performed by an electrophysiologist (also sometimes called an EP). The University of Michigan electrophysiology program has been a national and international leader in catheter ablation of arrhythmias (irregular heart rhythms) over the last three decades. We’ve been at the forefront of catheter ablation of atrial fibrillation during the last eight years and played a key role in understanding the mechanisms of atrial fibrillation and developing new treatment strategies.
Doctors at the University of Michigan have performed crucial studies that have helped to perfect the tools used in ablation. We handle large volumes of patients and have conducted extensive studies to prove that ablation is effective long term.
What is Catheter Ablation?
Catheter ablation is a minimally invasive technique intended to treat atrial fibrillation (Afib) without major surgery. Using a specially designed catheter that is positioned in the left atrium, radiofrequency energy is applied to the heart muscle to cauterize the “short circuits” that are triggering atrial fibrillation.
For the ablation procedure, catheters are inserted with a needle into a vein that runs up to the heart from the groin. The procedure requires the insertion of a catheter into the left atrium. This is accomplished by “transeptal catheterization,” in which a small hole is purposely made with a needle that is pushed through a thin membrane that separates the two top chambers of the heart.
With a computerized, three-dimensional mapping system to guide the procedure, the doctor can see the catheter and the left atrium on the computer screen, which makes it possible to guide the catheter very precisely and cuts down on the amount of X-ray needed during the procedure.
By recording the electrical activity inside the heart, we can identify the short circuits that are generating the atrial fibrillation. These spots are cauterized with the radiofrequency energy. To eliminate the atrial fibrillation, a typical patient requires between 150 and 250 different spots to be ablated.
The entire procedure usually takes 2 to 4 hours and the patient spends one night in the hospital. Patients are put on blood thinners for at least three months before and after the procedure, until the inner lining of the heart has healed from the effects of the radiofrequency energy.
Another type of ablation, known as cryoballoon ablation, uses liquid nitrogen instead of radiofrequency energy. Cryoballoon ablation precisely targets the multiple nerve connections around the opening of the pulmonary veins, which deliver oxygenated blood back to the left side of the heart. Pulmonary vein connections contribute to all types of atrial fibrillation — including paroxysmal and persistent — so it is important to target them during any ablation procedure.
A cryoballoon ablation procedure can be shorter than radiofrequency ablation, although both approaches are equally effective. With cryoballoon ablation, however, only pulmonary vein connections can be targeted. Radiofrequency ablation enables all types of arrhythmias (other than atrial fibrillation), which can coexist in up to 30 percent of patients, to be targeted.
During cryoballoon ablation, a catheter is threaded from the femoral vein in the groin to the pulmonary veins of the heart’s left atrium, followed by insertion of the cryoballoon catheter. The balloon, filled with liquid nitrogen, is positioned against the opening of the pulmonary veins and inflated. This causes the tissue touched by liquid nitrogen to become frozen, or scarred. This ablated tissue then can no longer trigger the electrical currents responsible for atrial fibrillation.
Success Rates for Catheter Ablation at the University of Michigan
We have performed thousands of ablation procedures aimed at curing atrial fibrillation over the past few years. Success rates of left atrial ablation in patients with atrial fibrillation depend on whether the atrial fibrillation is paroxysmal (the kind that comes and goes on its own) or persistent (the kind that has been present consistently for several months to years).
Paroxysmal atrial fibrillation can be eliminated in 70-75 percent of patients with a single procedure. When the procedure is repeated in patients who still have atrial fibrillation after the first procedure, the overall success rate is approximately 85-90 percent.
Persistent atrial fibrillation can be eliminated in approximately 50 percent of patients with a single procedure. In about 30 percent of patients who undergo ablation of chronic atrial fibrillation, the atrial fibrillation is replaced by a different kind of short circuit referred to as “left atrial flutter.” These patients are treated temporarily with medications and the left atrial flutter sometimes goes away on its own within a few months. If it does not, you may need a second catheter ablation procedure to eliminate the flutter. In these cases, the overall success rate is approximately 75-85 percent. If the atrial fibrillation has been persistent for more than 1-2 years, almost all patients will require more than one ablation procedure before a normal heart rhythm is restored.
Make an Appointment
The Arrhythmia Program at the University of Michigan has been a national and international leader in the treatment of arrhythmias for more than 30 years. To schedule an appointment to discuss catheter ablation or any other cardiovascular condition or treatment, call us at 888-287-1082 or visit our Make a Cardiovascular Appointment page, where you may fill out a Patient Appointment Request Form and view other details about scheduling an appointment.