Mitral valve prolapse in juvenile thyrotoxicosis.

To determine whether there is an association between mitral valve prolapse and juvenile thyrotoxicosis, we studied 13 thyrotoxic patients (3 males, 10 females, ages 8-17 years) by physical examination, chest radiograms, electrocardiograms and echocardiography. Five patients had an apical systolic murmur and two of these had echocardiographic evidence of mitral valve prolapse. The findings of mitral valve prolapse in 15% of the hyperthyroid patients and 1.7% in the control group suggests that this abnormality may be more frequent in hyperthyroid children. Echocardiograms should be performed in hyperthyroid children who present with an apical systolic murmur.