The Anatomic Basis of Connections Between the Coronary Sinus Musculature and the Left Atrium in Humans

Abstract

Background-This study determined the histological features of the atrial myocardium connecting the coronary sinus and the left atrium in humans. Methods and Results-Ten necropsied hearts were studied by performing serial longitudinal sections parallel to the long axis of the coronary sinus that extended its full length using a large microtome. In all specimens, the venous wall of the coronary sinus was surrounded by a cuff of striated muscle extending 40Ϯ8 mm from the ostium. Striated myocardial connections of varying number and morphology left this coronary muscle cuff and connected to the left atrium; they ranged from 1 to 2 fascicles to a widely intermingled continuum (thickness, 2.79Ϯ2 mm; width, 2.91Ϯ3.5 mm). These connections originated 8.8Ϯ5.7 mm from the coronary sinus ostium and inserted 18Ϯ11 mm distally into the left atrium. The insulating compartment in which the connections traversed between the left atrium and the coronary sinus was mostly formed of adipose tissue. The valve of Vieussens was found in 6 hearts at a mean distance of 3.4Ϯ3.2 mm from the distal extremity of the coronary sinus muscle cuff. Conclusions-In the human heart, a consistent but morphologically variable left atrial coronary sinus myocardial connection was found. This emphasizes the need for surgical dissection or catheter ablation in or around the coronary sinus to eliminate these connections. (Circulation. 2000;101:647-652.)

Characterization of Left Atrial Activation in the Intact Human Heart

“…6 Connections near the true interatrial septum had a dominant role during pacing from the RAS, such that right-to-left interatrial conduction was fastest and P-wave duration shortest during pacing from this site. These findings have important implications with regard to choice of pacing sites for atrial resynchronization to suppress AF.…”

Interatrial conduction can be accurately determined using standard 12-lead electrocardiography: Validation of P-wave morphology using electroanatomic mapping in man

“…[2][3][4] Nevertheless, based on the data available, it seems reasonable to conclude that Bachmann's bundle is the most common interatrial conductive route, although other routes, located posteriorly 6,7 and inferiorly, [8][9][10] also participate in interatrial conduction in most patients.…”

Three-dimensional Multiscale Modelling and Simulation of Atria and Torso Electrophysiology

“…As it was already introduced in previous section 6.2.2, several clinical studies of the human atria have histologically shown the existence of striated myocardial muscle at discrete locations along the sleeve of the CS that electrically connects CS and the LA myocardium (Chauvin et al 2000;Saremi et al 2011). The anatomy of these interatrial connections and their location have been previously shown as having high variability between patients.…”

“…Thus, tissue conductivities in each atrial region were adjusted as shown in Table 6.2 to match the activation sequences to the experimental data (Lemery et al 2007). Another relevant improvement has been carried out at tissue level in the CS-LA bridges since clinical and histological studies have shown the relevance of the striated myocardial muscles along its sleeve, connecting CS with the LA myocardium (Chauvin et al 2000;Saremi et al 2011). In that sense, the longitudinal conductivity on the first two proximal bridges has been increased up to (0.006 / • ) representing 7.5 times with respect to the four distal junctions (0.0008 / • to allow the wavefront to run at different velocities through these connections and reproduce a more realistic CS-LA propagation.…”

“…The anatomy of these interatrial connections and their location have been previously shown as having high variability between patients. This leads to strong differences in the pathway followed by the atrial depolarization wavefront (Chauvin et al 2000) and influences the BSPiM.…”