Detailed 3-D mapping of the heart’s anatomy. Tiny catheters that emit heat or cold energy. Sensitive instruments that pinpoint small disruptions in the body’s electrical signals.
They may sound like concepts drawn from a science fiction novel, but these advancements are being used by physicians who perform medical ablations to treat atrial fibrillation, a common heart condition. As a result, the procedure is now safer and more accurate for patients, according to University of Minnesota Health Heart Care experts.
Cardiac Electrophysiologists Henri Roukoz, MD, and Lin Yee Chen, MD, MS, are among a handful of University of Minnesota Health specialists who perform medical ablations for atrial fibrillation patients. Because of the increased effectiveness of the procedure, both say patients who received a medical ablation five or 10 years ago—and are once again experiencing atrial fibrillation symptoms—should consider a second ablation.
Atrial fibrillation, or AF, occurs when the electrical signals that tell the heart muscle when to contract—or “beat”—begin to misfire. These rogue signals interrupt the heart’s normal rhythm by causing the heart’s upper two chambers—the atria—to fibrillate, or contract irregularly and quickly. The condition is linked to a heightened risk for stroke, heart failure and dementia.
The medical ablation procedure was initially developed in the early 1990s, Chen said, when doctors discovered they could use catheters delivering hot energy to isolate or destroy the source of the misfiring signals. Now, specialists like Chen and Roukoz can conduct the ablation by inserting more sophisticated catheters through a blood vessel in the patient’s groin and threading it into the heart.
There, an electrode at the tip of the catheter produces heat (radiofrequency) or cold energy (cryoablation) to scar a small portion of heart tissue—often near the pulmonary vein, where the rogue signals frequently originate. The scar tissue effectively blocks the pathway used by the signals that cause the fibrillation, preventing future episodes in the majority of cases.
Though this approach is not new, catheter technology has evolved in the last decade, Roukoz said. The newest generation of catheters come equipped with a saline line that continually rinses the site of the ablation and pressure sensors that inform the doctors when the catheter tip is in contact with heart tissue. These advances reduce the risk of post-procedure complications and increase accuracy, Roukoz said.
Recent developments in diagnostic imaging technology have also led to improvements in medical ablations.
Doctors now use a cardiac MRI or CT scan to create a thorough, three-dimensional image of a patient’s heart anatomy before the procedure. This allows them to map out in detail their approach to the procedure. That heart map is supplemented with a special ultrasound scan just before the ablation, to ensure the patient doesn’t have any potentially risky blood clots in the heart. Doctors also rely on real-time, 3-D imaging during the procedure to help guide the catheters, Roukoz said. Finally, revised protocols for blood thinner use before and after an ablation have further reduced the patient’s risk of complications.
The entire procedure takes three to six hours, but typically only requires a single night’s stay in a hospital, Chen said.