[Interventricular communication with systolic occlusion]

Besides the ventricular defects of the "muscular" type with normal pressure values and which close during systole, there are ventricular septal defects in which systolic occlusion might be explained by other mechanisms; there are accompanied either by a stenosis of the outflow tract of the right ventricle (14 cases) or pulmonary hypertension (1 case). The diagnostic data were described, based mainly on the haemodynamic and angiocardiographic study. The hypotheses concerning the mechanism of occlusion in these cases were verified either on post-mortem or operative examinations.