The aim of this anatomic study was to evaluate both the extent and arrangement of atrial myocardial fibers in CVs in subjects with and without a history of AF. Twenty-five human autopsied hearts (15 men; mean age, 65.512 years; range, 39 to 80 years) were studied.
Seven subjects had a previous history of AF. The presence and morphology of atrial myocardial extensions were studied microscopically in both CVs.
Such extensions were found in 38 of 50 CVs (76%). There was no significant difference between patients with and without a history of AF.
Atrial myocardial extensions into both CVs are present in the majority of human beings, both with and without a history of AF. The extensions are localized on the outer side of venous adventitia.
Arrangement, length, and thickness of myocardial sleeves onto the CVs vary individually, and many of them contain degenerative changes.