- short fluoroscopy recordings of lead movements inside CS branching are taken in three radiological projections (posteroanterior, 30° right and left anterior oblique), both just before and immediately after the beginning of biventricular pacing at prefixed settings, which are: lower rate at 60-70 beats per min; atrioventricular (AV) delay at 120 ms and interventricular (VV) delay at 0 ms;