Ventricular aneurysm: pressure-volume relationships of a physical model.

Static pressure-volume characteristics were determined in elastic sacs with aneurysms of varying radius and wall thickness. Increasing the radius of an aneurysm lowered the maximal pressure (Pmax) which could be generated by contraction and deformed the pressure-volume curves compared with an intact sac of the same thickness. Progressive decrease in the wall thickness of an aneurysm of a given size resulted in progressive loss of pressure generated by any degree of filling. The present results suggest that shape, size and structure of the aneurysm and of the boundary between the normal myocardium and the aneurysm may contribute significantly to the impairment of the development of intraventricular pressure, and hence affect the contractile dynamics of the heart.