Oral disopyramide in the treatment of recurrent neurocardiogenic syncope.

In neurocardiogenic syncope the normal compensatory response on assuming an upright posture is interrupted after several minutes and replaced by a paradoxical withdrawal of sympathetic activity and increased parasympathetic activity. The resulting reduction in blood pressure is severe, sympathetic activity is inhibited, plasma norepinephrine levels do not increase and the heart rate decreases. The defect is a paradoxical interruption of sympathetic excitation associated with parasympathetic excitation, causing profound vasodilatation and bradycardia. Disopyramide has been shown not only to treat the bradycardia but also to control the hypotension.