CARDIAC-OUTPUT IN ASYMPTOMATIC PRIMARY HYPERPARATHYROIDISM - A STIGMAOF EARLY CARDIOVASCULAR DYSFUNCTION

The resting cardiac output pre- and postoperatively in 10 patients wit h asymptomatic primary hyperparathyroidism has been studied. All patie nts had normal renal function and arterial blood pressure without a pr evious history of cardiovascular disease. Ten normotensive patients wi th a non-toxic goitre awaiting thyroidectomy were studied as controls. The mean cardiac output of the hyperparathyroid patients was 7.2 l/mi nute (range 5.3-8.9) and of the control group 5.8 l/minute (range 5.2- 6.3). Following a successful parathyroidectomy with return of the seru m calcium to normal, the mean cardiac output was 6.3 l/minute (range 4 .9-7.8) (p<0.04). In 8 of the 10 patients there was a fall in the card iac output following surgery; in 2 there was an increase, These result s suggest that hyperparathyroid patients often have an elevated cardia c output which may fall following a successful parathyroidectomy.