Heart ailment treated in 3-D

By marrying two 3-D imaging technologies, heart doctors can use a stitchless, incisionless outpatient procedure to stop one of the most common and potentially dangerous heart arrhythmias: atrial fibrillation.

LDS Hospital's Dr. Peter J. Weiss last week presented the hospital's research to the 12th International Congress of Cardiology Meetings in Vancouver. The study looked at the first 49 LDS Hospital patients who underwent catheter ablation that was guided by new three-dimensional Magnetic Resonance Imaging paired with a 3-D electro-anatomic mapping system. It found that as many as 92 percent of patients with "highly symptomatic" atrial fibrillation who had not responded to medications were free of the arrythmia four months after ablation. Of those, nearly three-fourths no longer needed medication to treat the fibrillation, said Dr. John D. Day. Both Day and Weiss are cardiologists with the Utah Heart Clinic Arrhythmia Service at LDS Hospital.

The Framingham Heart Study said one in four people over their lifetime will develop atrial fibrillation, which results in electrical chaos of the heart's two upper chambers. It is caused by high blood pressure, genetics, heart failure or advancing age. Another national study found as many has half of heart failure patients experience atrial fibrillation, which can seriously worsen the heart failure.

Worst of all, said Day, about 25 percent of all strokes are believed caused by atrial fibrillation. Amid the electrical chaos, the heart's upper chambers don't pump blood, and if a resulting clot reaches the brain, it's a stroke. Simply having a diagnosis of atrial fibrillation increases mortality 2.5-fold.

Unlike some arrhythmias that correct themselves, atrial fibrillation left untreated may never stop. But though catheter ablation is used to treat some simpler arrhythmias, only recently has it been tried with atrial fibrillation.

The success of catheter ablation for atrial fibrillation is technology-dependent. "This study represents a new method of mapping out atrial fibrillation," Day said. For the 3-D electro-anatomic map, the physician places six electrodes on the skin and two catheters within the heart. One is fixed, the other moves to create a kind of global positioning satellite mapping system. Integrating the two imaging techniques "allows us to better visualize the heart and where the atrial fibrillation is coming from," he said. "It's a way to mimic what we do with surgery, but with the catheter."

The first step with atrial fibrillation is to try to prevent strokes, usually with a strong blood thinner like warfarin. Lower-risk patients may be treated with aspirin. Then the arrhythmia is treated.