[Anatomic study of the right ventricular inferior wall. Search for the optimal site for implanting epicardial pacing electrodes]

The inferior wall of the right ventricle was studied to determine the optimal site of implantation of epicardial pacing electrodes. The hearts of 10 patients without cardiac disease, aged 57 to 84 years, who died in Broussais hospital, were studied. The hearts were washed, weighed (300 to 550 g) and placed in a formol solution to which was added half its volume of Larsen's solution. They were then examined and cut in sections about 0,8 cm thick, perpendicular to the long axis of the heart. Each section was drawn and the thickness of the inferior right ventricular wall measured. The inferior wall of the right ventricle is shaped like a right angled triangle limited medially by the inferior interventricular groove, posteriorly by the atrioventricular groove (containing the right coronary artery), and laterally by the right free border. The surface area of the triangle varies between 14 and 34 cm2, a fatty border is always observed, and, in 5 out of 10 cases, vessels (arteries and veins) run in a randomised fashion across its surface. The inferior wall is very irregular on section, appearing craggy and cavernous with sudden variations of 1 to 10 mm in thickness due to the many 2nd and 3rd order trabeculations. In the muscular zone near the interventricular septum, the thickness varies from 2 to 10 mm, but only 10 out of 70 measurements were less than 4 mm. In the middle and central zones, only 34 out of 182 measurements were less than 4 mm thick. On the other hand, at the apex and right border of the heart, the values fell to 7 mm and parts of the anterior right ventricular wall was as thin as 0,5 mm.(ABSTRACT TRUNCATED AT 250 WORDS)