The Relief of Acute Right Ventricular Strain by the Production of an Interatrial Septal Defect

Since sudden resistance increase in the pulmonary circulation leads to right ventricular overdistension and subsequent failure, the question was studied whether or not the existence of an experimentally produced interatrial septal defect could prevent an overstretching of the right myocardium in acute pulmonary stenosis. It was found that myocardial overdistention could be prevented by a small interatrial septal perforation without essentially changing normal interatrial pressure relations. A large defect, which also protected the right heart muscle from overstretching, changed atrial pressure relations and cardiac dynamics entirely.