The effect of verapamil calcium antagonist on autonomic imbalance in migraine: evaluation by spectral analysis of beat-to-beat heart rate fluctuations.

Abnormalities in autonomic control have been documented in migraine even during the headache-free interval. It has long been recognized that spectral analysis of heart rate (HR) fluctuations can reflect the autonomic function, especially the sympathetic to parasympathetic balance. This technique is the basis for a quantitative approach to the investigation of migraine applied in the present study. A 24-hour Holter ECG recording was performed for each subject in a group of five migraine patients during the interheadache period. In addition, shorter 5-minute-long recordings of blood flow (BF) and blood pressure (BP) were made in these patients in both supine and standing positions. Short, 256-second subtraces were taken every 30 minutes along the 24-hour ECG signal and were submitted, as well as the BF and BP traces, to A/D conversion and computation of the power spectrum of fluctuations in HR, BF, and BP. Spectral analysis of fluctuations in these hemodynamic parameters was performed in the migraine patients before and during the treatment with verapamil and compared to that of a healthy control group. This procedure enabled us to assess the autonomic function, the sympathetic vs parasympathetic balance, and their response to a change in position, before and during calcium blockade. A characteristic autonomic abnormality is revealed in the group of untreated migraine patients in supine position: enhanced low frequency (LF) fluctuations reflecting increased sympathetic sensitivity during the inter-headache phase. An exaggerated sympathetic response is measured in the migraine patients during the transition from supine to standing position with a concomitant nonsignificant decrease in parasympathetic response.(ABSTRACT TRUNCATED AT 250 WORDS)