Postural dizziness and transient hypotension in two healthy teenagers.

Neurocardiovascular control during postural change was investigated in two teenage females with complaints of dizziness almost immediately on standing up. Blood pressure and heart rate were monitored continuously with a Finapres device. On standing there was a brief but marked fall in blood pressure between 5-10 s after the onset of the manoeuvre. The maximum fall in systolic and diastolic blood pressure was 65 mmHg and 40 mmHg respectively in the first subject, and 58 mmHg and 29 mmHg respectively in the second subject. In both, postural tachycardia was present after 1-2 min of standing with heart rate increasing by up to 39 beats/min in the first subject and 60 beats/min in the second subject. On a follow-up examination 3 years later these changes had disappeared in the first subject while they persisted in the second subject, when she was studied two years later. We conclude that in these patients initial postural dizziness is related to an excessive fall in blood pressure upon standing.