Migraine patients seem to suffer from a continuous autonomic imbalance. Sympathetic instability, expressed by enhanced low frequency fluctuations, which exists during the headache free intervals, was observed in our previous study by spectral analysis of heart rate (HR) fluctuations. Propranolol--a beta adrenoceptor antagonist, is widely used in migraine prophylaxis. In order to specify and quantitate propranolol efficacy in migraine, spectral analysis of heart rate fluctuations was performed on 10 migraine patients before and during the treatment with propranolol. They were compared to 10 healthy control patients and 6 migraine patients who were treated for several months with propranolol and then discontinued the medication. The analysis was carried out on a 24h Holter ECG recording, which was performed for each subject during a headache free interval. Short 256 sec subtraces, taken every 30 min from the 24h ECG signal, were submitted to A/D conversion, R wave detection and computation of heart rate power spectrum. Propranolol achieved a marked effect, when comparing the power spectra of HR fluctuations in treated versus untreated migraine patients. A strong reduction (to normal level) in the low frequency HR fluctuations in the range below 0.1 Hz., was apparent in patients treated with propranolol. Subjects who had received propranolol in the past and discontinued the drug, displayed a carry-over effect of reduced fluctuations even 2-3 months after its discontinuation. It seems that the propranolol efficacy in migraine is associated with the mechanism of stabilizing the fluctuations within the frequency band related to sympathetic activity, hereby moderating the vascular instability in migraine.

We have designed a prospective observational study to analyze the incidence and predictive factors of atrial fibrillation (AF) during a long follow-up, in a large population. Atrial fibrillation episodes were documented by the fallback mode switch (FMS) provided by implanted pacemakers. We have included 377 patients (61% men). The pacing indications were atrioventricular (AV) block (49%), sinus node disease (SND, 16%), bradycardia-tachycardia syndrome (BTS, 5%), AV block + SND (19%), AV block + BTS (6%), and BTS + SND (5%). The mean age at implant was 75 +/- 12 (range 28-95). Atrial fibrillation before inclusion was documented in 10% of patients. Drug therapy at first follow-up included beta-adrenergic blockers (17% of the patients), amiodarone (13%), and others (16%). The mean follow-up was 30 +/- 24 weeks. At least one AF episode was stored during follow-up in the memory of 169 pacemakers (45%). Among patients without history of AF at implant, 46% had documented FMS during follow-up. Patients with AF received more antiplatelet medications than patients without AF (P = 0.03). In patients with AF, New York Heart Association functional class was slightly higher, amiodarone and sotalol were more often prescribed, and the proportion of hypertension was higher than in patients without AF. However, these trends were not statistically significant. A significant higher incidence of premature atrial beats was observed in patients with AF than patients without AF (P < 0.0002). Patients with AF had a lower atrial percentage of paced events (55%) than patients without AF (63%, P < 0.02). These preliminary results confirm the high incidence of AF in paced patients and suggest a preventive effect of atrial pacing. The effects of other clinical variables may be confirmed with a longer follow-up in a larger population.