abnormal heart development abnormal heart interventricular foramen morphology 2024-01-09T11:31:14Z any structural anomaly of the temporary opening (space) between the free rim of the muscular interventricular septum and the fused endocardial cushions, allowing for communication between the developing right and left heart ventricles; in normal development, the interventricular foramen closes off when the septum fuses with the endocardial cushions and bulbar ridges to form the membranous part of the interventricular septum MPheno.ontology Failure to close the interventricular foramen leads to an interventricular septal defect known as a patent interventricular foramen. abnormal primary interventricular foramen morphology abnormal cardiac interventricular foramen morphology MP:0031565