By contrast, it is thinnest, at 2.2 [+ or -] 0.3 mm, at the right or left venoatrial junctions .
Postmortem examination in human specimens showed in most hearts an abrupt change of subendocardial fiber orientation (circumferential, oblique, and longitudinal) in the posterior wall of the LA (Figure 2(c)) at the venoatrial junctions.
However, the focus of ablation strategies shifted from the PV ostium to the atrial tissue located in the venoatrial junctions due to the fact that many non-PV trigger points for AF are located in the venoatrial junctions rather than the PV and that radiofrequency catheter ablation (RFCA) techniques may cause PV stenosis .
In our histological study on 65 veins , the thickness of the smooth muscle ranged from 0.05 to 1 mm at the venoatrial junction, diminishing to 0.03-0.5 mm at a distance of 10 mm from the junction.
In 20% of specimens, it descended close to the right venoatrial junction; in the remaining cases, it had a leftward course close to the left venoatrial junction .