The middle cardiac vein as a key for "posteroseptal" space--a morphological point of view.

About 25% of accessory pathways (AP) run via "posteroseptal" space (PSS). There are three approaches for ablation of these pathways: from the right atrium, from the left atrium or from the ventricle and coronary sinus (CS). However in some cases AP is too far from all of them. Catheterisation of the middle cardiac vein (MCV) seems to be the only chance for successful ablation. Our aim was to evaluate the topography of the MCV in PSS. Classical anatomical investigation was carried out on the autopsy material of 98 consecutive human hearts (42 F, 56 M; age 57 +/- 21 yrs). It was supported by transverse section performed under coronary sinus. Regions just behind the atrioventricular septum and behind the cavities were respectively classified as "septal", right (RP) and left posterior (LP). Between them right (RPS) and left posteroseptal areas (LPS) were present. At the posterior view of the heart the angle between CS and MCV ranged from 75 to 90 degrees in 62% of hearts, 60-75 degrees in 18%, 30-60 degrees in 10% and 90-130 degrees in 10%. In 16% MCV ran via the "septal" region, 59%--LPS, 10%--RPS, 10%--RP and 5%--LP. At the ostium of 58% MCV a valve was observed, however there was no trouble with insertion of the 6F catheter into it. We concluded that it is possible to insert the 6F catheter into MCV, which makes it possible to perform ablation of epicardial postero-inferior accessory pathways. The origin of MCV is usually located in the left "posteroseptal" region and runs towards the left side of the posterior wall.