Fig. 2

Stepwise approach to placement of the steerable-curve electrode into a coronary sinus via the femoral vein. Generally, a fixed-curve quadripolar electrode was placed into the apex of right ventricle (as shown in blue bands); then His potential was recorded by the electrode and marked by yellow dot. a First, the steerable electrode was advanced to the position about one centimeter below the position of his potential or peak of tricuspid valve. b Secondly, it was flexed toward the right ventricle. c Thirdly, it was rotated backward to locate the orifice of coronary sinus. d Fourthly, the electrode was extended gently. e Finally, the tip of electrode was advanced distally into coronary sinus. The solid arrow and blank arrow showed the track of catheter tip in RAO and LAO, respectively