Cluster headache: heart rate and blood pressure changes during spontaneous attacks.

The ECG findings before, during and following 81 spontaneous attacks of cluster headache in 24 patients have been recorded using a Holter cardiography system. No significant change in mean heart rate was found during attacks, when all attacks were considered as a group. Attacks which began when patients were awake differed from those which began during sleep as regards changes in mean heart rate. The mean heart rate decreased during the majority (61%) of attacks which began when patients were awake, whereas it remained unchanged or increased during the majority (67.5%) of attacks which began during sleep. The attacks which began when patients were awake also had higher absolute mean heart rate values before, during and following attacks compared to similar values for those attacks which began during sleep. blood pressure was measured during 11 attacks and showed a significant increase in both systolic and diastolic blood pressure. The heart rate and blood pressure in six patients usually increased during induced head pain.