Anatomical relationship of coronary sinus/great cardiac vein and left circumflex coronary artery along mitral annulus in atrial fibrillation before radiofrequency catheter ablation using 320-slice CT.

PURPOSE: We evaluated anatomical relationships between the coronary sinus and great cardiac vein (CS/GCV) and left circumflex coronary artery (LCX) along the mitral annulus (MA) in patients with atrial fibrillation (AF) using 320-slice CT.

METHODS: Fifty-three patients with AF (44 males; mean 63 ± 11 years; 28 paroxysmal, 10 persistent, and 15 permanent AF) underwent 320-slice CT. Double-oblique CT images perpendicular to the MA short axis were created every 10° for 36 circumferential sections. The angle of 0° corresponded to the 12 o'clock position.

RESULTS: CS/GCV-MA distance was greatest in the posterolateral MA. CS/GCV diverged from the LCX more widely in the lateral through posterolateral MA than the anterior through anterolateral MA. CS/GCV crossed the LCX in 51 patients (96.2%) and left main coronary artery in 2 patients (3.8%). Median angle of the CS/GCV-LCX crossing point was at 40° but ranged widely (0° to 150°) and was more frequent in the anterior and anterolateral MA than in the lateral, posterolateral, and posterior MA (31.4%, 45.1%, 11.8%, 11.8%, and 0%, respectively; P<0.01). CS/GCV crossed over the LCX in 39 patients and under the LCX in 12 patients. Range of the CS/GCV-LCX overlapping course increased significantly as the CS/GCV-LCX crossing point neared the CS ostium. Correlation coefficient between the range of the overlapping course and crossing point angle was 0.78.

CONCLUSIONS: Anatomical relationships between CS/GCV and LCX greatly varied in location and proximity among AF patients. Interventional electrophysiologists should know the potential risk for LCX injury when radiofrequency energy is delivered within the CS/GCV.