Prolonged asystole provoked by head-up tilt testing.

We describe a patient with a history of neurocardiogenic syncopes who had a positive headup tilt test that resulted in an lasting asystole lasting 34 seconds. However, the previously carried out Schellong test with a 30-min phase of standing showed a normal result. The patient showed typical orthostatic symptoms while tilted at the angle of 75 degrees. Shortly before asystole occurred, heart rate variability showed high frequency bands, indicating vagal stimulation. The pathophysiology of neurocardiogenic syncope (NCS) in context with heart rate variability is discussed. This patient was successfully treated with propranolol. This case shows the utility of a provocative head-up tilt test in establishing the diagnosis of NCS. If the Schellong test is normal, still further examination by tilt-table test is indispensable.