Isolated Pulmonary Valvular Regurgitation Complicated by Thyrotoxicosis.

Pulmonary valvular regurgitation occasionally develops in the course of bacterial endocarditis due to erosion or perforation of the valve cusps. It also may occur in patients with chronic pulmonary hypertension secondary to obstructive lesions in the left side of the heart or in the pulmonary blood vessels. In these latter circumstances, the regurgitation is thought to be due to stretching of the valve ring, and it is manifested clinically by the well-known high-pitched early diastolic GrahamSteell murmur. Isolated pulmonary valvular regurgitation is less common. It may result either from congenital absence or deformity of valve tissue or from idiopathic dilatation of the pulmonary artery. In the past six or seven years, increased clinical awareness of this condition, together with the opportunity for definitive diagnosis by cardiac catheterization and selective angiocardiography, has led to an increasing number of reported cases. Thus, while the first case diagnosed during life was reported in 1953, there are now 26 published cases (Laneve, Uesu, and Taguchi, 1962). The most interesting physiological sequela of the valvular lesion is the hyperdynamic activity of the right ventricle. This is analogous with that found in atrial septal defect (Collins, Braunwald, and Morrow, 1960), a condition which is also characterized by an increase in the output of the right ventricle. The present case is, therefore, of unusual interest in that the patient had an additional disease, thyrotoxicosis, which also is associated with a hyperdynamic state of the circulation.