Quantitative study of nerves of the human left atrium.

Objectives: To quantify and study the distribution of innervation of the left atrium and the pulmonary veins in humans.

Background: Damage to cardiac nerves has been hypothesized as the explanation for successful radiofrequency ablation of atrial fibrillation.

Methods: From January 2003 to September 2003, histologic and quantitative studies of innervation of the left atrium and the pulmonary veins was performed in 43 consecutive necropsied adult hearts (30 men and 3 women; mean age 45.