An observational study just published in the Journal of Cardiovascular Electrophysiology provides evidence that significant atrial fibrosis is associated with clinically significant sinus node dysfunction (SND) requiring pacemaker implantation. Moreover, the results indicate that fibrosis related to atrial fibrillation (AF) affects the left atrium more than the right, which is consistent with the focus of AF research and therapeutic intervention.

The study included 344 AF patients at the University of Utah who were evaluated prior to ablation using delayed enhancement MRI and the Utah Staging System to quantify the extent of fibrosis in their left and right atrial.

According to the study’s lead author, clinical electrophysiologist Dr. Nazem Akoum, “the risk ratio for requiring a pacemaker implant was significantly higher for patients in Utah stages 3 or 4 compared to those in Utah stage 1 or 2. This is the first time a non-invasive method was used to identify groups of patients who may be at greater risk for the need of implants.”

Dr. Akoum also remarked that the study was the first to provide quantifiable evidence that the fibrotic structural remodeling process is much less pronounced in the right atrium compared to the left. Some of its other notable findings and observations included:

• Structural remodeling throughout the atrium, and in the sinus node region, may be less reversible than electrical remodeling.
• The predictive value of atrial fibrosis was a more important predictor than clinical parameters such a patient’s age, gender or the clinical AF type, and may be of important clinical value in regards to managing the full spectrum of the tachycardia-bradycardia syndrome.

Dr. Akoum specializes in catheter ablation, pacemaker and defibrillation research at University of Utah’s Comprehensive Arrhythmia Research & Management Center (CARMA). If you’d like to discuss this study or his other research projects, you can contact him at 801-213-2387 or nazem.akoum@hsc.utah.edu.

Nassir F. Marrouche, MD is the Executive Director of the Comprehensive Arrhythmia Research & Management Center, Director of Electrophysiology Laboratories, and Director of the Atrial Fibrillation Program at the University of Utah School of Medicine, Division of Cardiology.