Increased sympathetic activity and blood pressure in young asymptomatic men with 'organic' T-wave aberrations in the electrocardiogram.

1. Twelve asymptomatic young men with 'primary' T-wave aberrations in the electrocardiogram (group T) and 13 matched controls were subjected to a mental stress test, isometric exercise and a cold pressor test. 2. Plasma catecholamines and haemodynamics were studied. 3. Group T had signs of increased sympathetic activity at rest and enhanced sympatho-adrenal reactivity during stress. 4. Systolic blood pressure was consistently elevated in group T. 5. The T-wave aberrations may be explained by the increased sympathetic activity. 6. Several similarities exist between group T and borderline hypertensive subjects.