Anatomic obstacles for catheter manipulation in GCV
For catheter ablation of DGCV-AIV VAs, a thorough understanding of CVS
anatomy is essential[1,2]. The coronary sinus is
located at the posterior and inferior part of the epicardial mitral
valve and collecting the blood from CVS, ends in the right atrium. There
is a small folded tissue known as Thebesian valve at the ostium of the
coronary sinus, which might occasionally be an obstacle to
catheterization. A small left atrial vein named Marshall (or Marshall
ligament) is the remnant of the embryonic left superior cardinal vein
and drains into the coronary sinus. It is at the point where Marshall
vein drains into coronary sinus that coronary sinus turns into the great
cardiac vein, 29.15% of patients have a well-developed Vieussens valve
at this site that might preclude ablation catheter advancement. The GCV
goes along the lateral portions of the mitral valve and extends into
DGCV at epicardium of the anterolateral portion of mitral annulus. It is
reasonable to believe that a curved GCV morphology may limit the
advancement of catheter. DGCV turns into AIV beneath the aortic valve
cusp at the left ventricular summit. The angle between AIV and DGCV2 has
great individual variability. It is observed that an acute angle between
AIV and DGCV2 would prevent the ablation catheter reaching proximal AIV,
on the contrary, an obtuse angle would facilitate catheter performing
mapping and ablation in proximal AIV. Communicating vein refers to the
very thin veins between the GCV and conus branch that drains to the
small cardiac vein, and Summit-CV is a distinct CV that is located
between the aortic and pulmonary annulus, distal to the transitional
area between the GCV and the AIV, and in close association with the
superior portion of the LV summit. Previous studies have revealed
summit-CV can be the source of idiopathic ventricular arrhythmias.
However, the very thin lumen of this vessel usually limits the detailed
mapping and ablation in this region. Above all, hamper of venous valves
(Thebesian valve and Vieussens valve), deflections of GCV, acute angle
between DGCV and AIV, thin lumen of Summit-CV, are all potential
anatomic factors preventing catheter ablation of DGCV-AIV VAs.
Therefore, any method, which could assist ablation catheter overcoming
these anatomic obstacles, would contribute to the successful ablation of
DGCV-AIV VAs. Figure2 .
In this study, the angle between AIV and DGCV, and width/ height of GCV
in each patient was measured by three electrophysiologists independently
in the individualized LAO view (under this view, the course of GCV was
sufficiently unfolded and clearly visualized), a mean value was adopted
for statistical analysis. The height of GCV was defined as the maximal
vertical distance from the beginning of AIV to the proximal GCV. The
width of GCV was defined as maximal transversal distance from lateral
GCV to the maximal vertical line.