Variation of anatomical structures related to biventricular pacing procedures and cannulation of the coronary sinus

The success of biventricular pacing procedures is at least partially related to the ability to implant leads into the heart. Lead placement into the coronary sinus can be particularly challenging because of variations in the coronary venous anatomy. We examined the anatomy of the coronary sinus and the Thebesian valve. Forty-three (22 male, 21 female) embalmed adult cadavers were used to determine the internal diameter of the coronary sinus ostium, the presence of a membranous or fenestrated Thebesian valve, and the percent occlusion of the coronary sinus ostium by the Thebesian valve, if present. An 8-French (F) guiding catheter was used to simulate coronary sinus cannulation. The average internal diameter of the coronary sinus ostium was 11.44 ± 3.21 mm. A Thebesian valve was present in 74 % of the cadavers, and the majority (84 %) of those valves were membranous. In the presence of a Thebesian valve, the opening at the ostium was reduced to 7.47 ± 2.69 mm. The percent occlusion of the coronary sinus ostium by the Thebesian valve varied from 8.26 to 100 %. The average cannulation distance (length of catheter travel into the coronary sinus from the coronary sinus ostium) was 69 ± 18 mm. Statistical analyses revealed no gender differences in the measurement data for either the coronary sinus or Thebesian valve. The most common presentation is a membranous Thebesian valve. Most frequently, the percent occlusion ranged between 41 and 50 %. The cannulation distance was greater in males than in females.