Determination of pressure in the pulmonary artery by external graphic recordings.

Pulmonary hypertension is a fundamental prob- lem in the study of diseases of the heart and lungs. Because of its importance with regard to pathogenesis, clinical manifestations, and indications for surgery, it has been the object of numerous studies. At present, however, quantitative determination of pulmonary arterial pressure can be made satis- factorily only by cardiac catheterization.