Anatomy of the left atrial ridge (coumadin ridge) and possible clinical implications for cardiovascular imaging and invasive procedures

Abstract

Background: The left atrial ridge is a structure located in the left atrium between the left-sided pulmonary veins ostia and the orifice of the left atrial appendage. Since it was commonly misdiagnosed as a thrombus, the ridge is also known as the "coumadin" or "warfarin" ridge. The left atrial ridge is a potential source of arrhythmias and can be an obstacle in ablation procedures. This study aimed to provide information about the occurrence and spatial morphometric characteristics of the left atrial ridge. Methods and Results:The macroscopic morphology of the left atrial ridge was assessed in 200 autopsied human hearts. The ridge was observed in 59.5% of specimens and was absent in the remaining 40.5% of cases. The mean length of the ridge was 22.4 ± 5.1 mm. It was wider at its inferior sector when compared to its superior sector (9.1 ± 5.0 vs 7.9 ± 3.2 mm; P = .028). The total wall thickness measured at the cross section of the ridge was significantly larger in the inferior than in superior sector (6.2 ± 3.5 vs 4.3 ± 1.8 mm; P < .001), although the myocardial thickness was significantly larger at the superior sector (3.1 ± 1.4 vs 1.9 ± 0.9 mm in inferior sector, P < .001). Conclusion:The left atrial ridge is a variable structure, present in 59.5% of humans.The ridge is significantly wider and thicker at its inferior sector, although the actual myocardial layer present within the ridge is thinner at this location. Knowledge about the left atrial ridge morphology is key in avoiding unnecessary interventions or complications during invasive procedures. K E Y W O R D S ablation, atrial fibrillation, coumadin ridge, endocardial ridge, left atrial appendage, left atrial lateral ridge, left atrial pseudotumor, left lateral ridge, pulmonary veins, warfarin ridge

Ethanol infusion into the vein of Marshall for recurrent perimitral atrial tachycardia after catheter ablation for persistent atrial fibrillation

“…RF ablation is sometimes difficult to achieve transmural lesion due to the thickness of atrial wall, for example, in the left lateral ridge which is both part of MI and insertion of epicardial connection. 17 The left circumflex artery, CS" and great cardiac vein locate in the middle to lower part of epicardial MI, causing a heat sink effect that further hinders the delivery of RF energy, but intensive RF application should be avoided in these cases to minimize the risk of injury to the vessels. 3 Moreover, epicardial connections are common and usually have multiple insertions to the left atrium.…”

Abutting Left Atrial Appendage and Left Superior Pulmonary Vein Predicts Recurrence of Atrial Fibrillation After Point-by-Point Pulmonary Vein Isolation

“…The occurrence of a prominent fold is likely when the LSPV and LAA are in a close anatomical relationship. In such cases, the ridge might be even thicker, which could result in a worse AF-free survival after ablation ( 22 ). Another previous study found that bilateral ridge ablation improves arrhythmia-free survival compared to PVI-only in case of paroxysmal AF ( 23 ).…”

Acute left atrial ridge lesion after cryoballoon ablation: How does this affect left atrial appendage closure combined procedure?

“…The LAR is an invagination located between the left PVs and the LAA. A recent cadaveric study by Piątek‐Koziej et al 1 revealed that the appearance of LAR varies, with an average width of 7.9 ± 3.2 mm and whole wall thickness of 4.3 ± 1.8 mm at the LSPV ostium. However, in our study, we measured a smaller preprocedural width of 5.2 ± 1.6/5.7 ± 2.2 mm and a larger thickness of 11.0 ± 3.8/13.1 ± 4.1 mm at 45°/90° planes.…”

“…The left atrial ridge (LAR)—also known as the coumadin ridge—is a protruding structure located between the left atrial appendage (LAA) and left pulmonary veins (PV). The LAR is also a potential source of arrhythmias and a site of ablation, where it is close to autonomic nervous fibers, Bachmann's bundle, and Marshall′s ligament 1 . LAR had long been a site for atrial fibrillation (AF) ablation 2 and one of the differential diagnosis points of high‐echo band on echocardiography 3 …”