A 48-Hour Holter ECG Study in Migraineurs during Usual Daily Activities

In order to clarify the condition of cardiac autonomic nervous activity in migraineurs, 48-h Holter electrocardiograms (ECGs) were carried out under free activity on 20 migraineurs during headache free periods and 20 healthy controls. We calculated hourly standard deviation (SD), root mean square successive differences (RMSSD), the proportion fo cycles during which the RR difference is > 50 ms (%RR50), low frequency heart rate fluctuation (LF), high frequency heart rate fluctuation (HF) and LF/HF ratio from heart rate variability, and obtained serial 24 data of these parameters. SD, RMSSD, %RR50 and HF are parasympathetic parameters, and LF/HF is sympathetic. These parameters were fit to cosines curve and analyzed circadian rhythms using the cosinor method. By group mean cosinor analysis, the vectors of the amplitude-acrophases of SD, RMSSD, %RR50, LF, HF and LF/HF significantly differed in the migraineurs from those in the controls. The significant differences of vectors of SD, RMSSD, %RR50 and HF indicate cardiac parasympathetic dysfunction. Midline estimating statistic of rhythms (MESORs) of those parameters did not significantly differ except in LF and LF/HF between both groups. MESORs of LF and LF/HF were significantly decreased in the migraineurs, which indicates cardiac sympathetic hypofunction. We concluded that migraineurs might have cardiac parasympathetic dysfunction and sympathetic hypofunction. By evaluating circadian rhythms using cosinor methods, the parameters of heart rate variability in migraineurs were significantly different from controls. Migraineurs may have some disturbance in their rhythm generator.