Chapel Hill, N.C. — Doctors develop a trained eye to interpret two-dimensional X-rays or ultrasound images.

But when cardiologists need to scar the inside of the heart to treat atrial fibrillation, a flat picture may require some guess work.

The U.S. Food and Drug Administration just approved a system to help doctors see the heart and their instruments in real time from any angle.

The EnSite Velocity Cardiac mapping system treats patients with arrhythmia. It combines CAT Scan, ultrasound imaging and special computer software for a three-dimensional image.

Dr. Paul Mounsey, a cardiologist at UNC Hospitals, threads catheters tipped with electrodes into the heart which he can see in real time. Mounsey places “burns on the inside of the heart to break up the electrical short circuits within the heart.”

The procedure helps the heart return to normal rhythm, but it may not work if there's a gap between burns.

“So three-dimensional imaging is essential to know where our instruments are inside the heart,” Mounsey said.

The minimally invasive procedure has a success rate of up to 90 percent. It also means a shorter procedure time and less exposure to radiation.

Most patients who develop atrial fibrillation can be treated with medication, but some do need either surgery or a procedure like catheter ablation inside the heart.