Cluster headache: alterations in heart rate, blood pressure and orthostatic responses during spontaneous attacks.

Changes in heart rate and blood pressure (BP) have been monitored beat-to-beat in a cluster headache patient with and without attacks using a non-invasive Doppler servo method. Two attacks were monitored and during one of them a tilt test was carried out. The variability of heart rate and BP was greater during the attack than during the interparoxysmal period. A marked bradycardia occurred during attacks. Systolic BP increased slightly. There was no heart rate increase after tilting during the attack, whereas this was present invariably during tests carried out interparoxysmally. BP changes during "attack tilt" were difficult to evaluate because of large variation. This may be the first observation of a baroreflex arc dysfunction during a cluster headache attack.