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.

The Dynamics of Eisenmenger's Complex

Pulmonary venous blood and pulmonary venous pressure were obtained by catheterization technic in a case of Eisenmenger's complex with anomalous pulmonary venous drainage into the right auricle. This made possible measurement of the true total pulmonary vascular resistance and evaluation of a pulmonary factor in the cyanosis accompanying this anomaly. No evidence for inadequate oxygenation in the lungs was apparent, and it is concluded that the cyanosis in Eisenmenger's complex is due solely to venoarterial shunting.

Transposition of the Aorta and Pulmonary Artery

Transposition of the aorta and pulmonary artery is now more frequently diagnosed in life. It must be distinguished from Fallot's tetralogy because it is not helped by the Blalock-Taussig operation: indeed, the blood flow to the lungs is increased instead of reduced. This picture of pleonemic lungs can be recognized by radioscopy and indicates a left to right shunt; when combined with central cyanosis, complete or partial transposition is the most common cause. The general picture seen in 25 cases, in 6 of which the diagnosis was confirmed by cardiac catheterization and angiocardiography, is described. Two cases where the features of transposition were obscured by the presence of pulmonary stenosis are included.