Surgical Therapy of Atrial Fibrillation

Abstract

Atrial fibrillation (AF) affects about 2 % of the general population. It is strongly correlated to age, and the prevalence increases to 10–15 % in patients over the age of 80. It is associated with hypertension, heart failure, valvular heart disease, and ischemic heart disease. In 10–15 %, there is no underlying cardiac pathology present (lone AF).

AF requires both an initiating event and a permissive atrial substrate. While automaticity and triggered activation is often, but not exclusively, found within and around the pulmonary veins (PVs) and is involved in AF initiation, different mechanisms of reentry in both atria play also an important role in sustaining AF. As the atrial size increases, the conduction velocity is slowed, or the atrial refractory period is decreased, and the probability of initiating and sustaining AF increases.

Besides symptoms, the hemodynamic compromise, and tachycardia-induced cardiomyopathy, stroke remains the most feared complication. AF accounts for about 25 % of strokes in patients older than 80 years and increases a person’s risk of stroke by fivefold.

The surgical procedures currently performed to ablate AF include the biatrial Cox-Maze procedure, left atrial lesion sets, and pulmonary vein isolation. All of these operations have been simplified by alternative energy sources.

Success rates vary and depend on the lesion set performed, the energy source used, the type of AF, and the presence of concomitant pathology. The biatrial Cox-Maze procedure has an approximately 90 % success rates for all types of AF and has set the benchmark for alternative lesion sets as well as for new and less invasive approaches currently under development.