SYMPATHETIC-PARASYMPATHETIC ACTIVATION DURING SPONTANEOUS ATTACKS OF CLUSTER HEADACHE - EVALUATION BY SPECTRAL-ANALYSIS OF HEART-RATE FLUCTUATIONS

Twenty-four hour ECG Holter and blood-pressure monitorings Mere perfor med in eight patients suffering from cluster headache. Spectral analys is of heart-rate fluctuation was used to assess the autonomic balance under basal conditions, after head-up tilt, and during a spontaneous a ttack, Normal autonomic balance was found at rest and during sympathet ic activation obtained with head-up tilt in the interparoxysmal period . Before the onset of headache, an increase in the low-frequency (LF) component of the power spectrum was apparent in all patients. This sig n of sympathetic activation was followed by an increase in the high-fr equency (HF) component that developed about 2000 beats after the onset of headache and rapidly overcame the LF component until the end of pa in. Significant differences were found when comparing the spectral par ameters [total spectral values (TP), power of the LF and HF components and LF/HF ratio] obtained before, during and after headache. During t he attack, blood pressure increased and heart rate decreased in all su bjects. There appears to be a primary activation of both sympathetic a nd parasympathetic functions in cluster headache attacks. The sympathe tic component seems to be involved mostly in the development of the at tack, whereas the parasympathetic activation seems to occur, following the onset of the attack, independently of the pain.