Heart rate response, emotional disturbance and hyperventilation.

The heart rate and electrocardiographic responses were documented in 40 subjects undergoing hyperventilation provocation tests. Forced overbreathing produced a similar mean heart rate increase in all subjects, regardless of whether the result of the provocation tests suggested the hyperventilation syndrome. In contrast subjects diagnosed as hyperventilators by virtue of prolonged hypocapnia in response to psychological provocation showed significant increased heart rate responses compared to the remaining subjects (p less than 0.001). Significant electrocardiographic abnormalities were also produced. The view is presented that the hypocapnia may allow persistence of the cardiovascular responses in the presence of emotional challenge.