Observations on midodrine in a case of vasodepressor neurogenic syncope.

A 43-year-old man presented with recurrent syncope and dizziness after he had a dual chamber pacemaker fitted for presumed sino-atrial disease. Head-up tilt produced vasodepressor neurocardiogenic syncope, despite appropriate heart rate support during pacing, and reproduced symptoms. Symptoms were not improved by disopyramide. A double-blind cross-over trial of midodrine, an alpha-receptor agonist, was effective in reducing symptoms: it abolished syncope and reduced frequency and severity of dizziness, coupled with improved haemodynamic responses to head-up tilt.