Dynamics of heart failure in ventricular aneurysm studied by a physical model

Utilizing a model of ventricular aneurysm of varying size and wall thickness produced on a layered thin-walled elastic sac (original ventricle), the static pressure-volume relationships of the ventricle-aneurysm system were determined. Progressive increase in the size of an aneurysm lowered the intracavitary pressure obtained in the system. Decreasing the wall thickness of an aneurysm also decreased the developing pressure in the system. The results indicate that intraventricular pressure to be developed, being common to both ventricle and aneurysm, largely depends on the volume of the remaining intact myocardium of the original ventricle and the mechanical characteristics of the aneurysm, i.e., size, elasticity and wall thickness of the aneurysm. The maximum pressure generated in a thin-walled aneurysm is directly proportional to the wall volume and Young's modulus, and inversely to the unstressed volume (initial radius) of the aneurysmal sac.