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 ev en during the headache-free interval. It has long been recognized that spectral analysis of heart rate (HR) fluctuations can reflect the aut onomic function, especially the sympathetic to parasympathetic balance . This technique is the basis for a quantitative approach to the inves tigation of migraine applied in the present study. A 24-hour Holter EC G recording was performed for each subject in a group of five migraine patients during the inter-headache period. In addition, shorter 5-min ute-long recordings of blood flow (BF) and blood pressure (BP) were ma de in these patients in both supine and standing positions. Short, 256 -second subtraces were taken every 30 minutes along the 24-hour ECG si gnal and were submitted, as well as the BF and BP traces. to A/D conve rsion and computation of the power spectrum of fluctuations in HR, BF, and BP. Spectral analysis of fluctuations in these hemodynamic parame ters was performed in the migraine patients before and during the trea tment with verapamil and compared to that of a healthy control group. This procedure enabled us to assess the autonomic function. the sympat hetic vs parasympathetic balance, and their response to a change in po sition, before and during calcium blockade. A characteristic autonomic abnormality is revealed in the group of untreated migraine patients i n 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 concomi tant nonsignificant decrease in parasympathetic response. Under the in fluence of verapamil, the enhancement in low frequency fluctuations is reversed as well as the exaggerated sympathetic response to standing.