Normal heart rate variability in colchicine-resistant familial Mediterranean fever patients

Background: The relationship between autonomic nervous system (ANS) dysfunction and familial Mediterranean fever (FMF) is controversial. We recently reported normal heart rate variability (HRV), suggestive of normal ANS, in patients with uncomplicated FMF. Objectives: To evaluate ANS function in colchicine nonresponders by using the HRV tool. Methods: The study group comprised 24 FMF patients suffering from recurrent FMF attacks despite treatment with a maximal colchicine dose. Electrocardiogram was measured under strict conditions and HRV parameters were calculated. Results were compared with age- and gender-matched unaffected controls. Results: No statistically significant difference was found between the groups in any of the HRV parameters: maximal RR, minimal RR and average RR intervals, standard deviation of RR interval, square root of the mean squared differences of successive RR intervals, HRV triangular index, NN50, pNN50, and power spectral analysis parameters. Conclusions: Although a small difference in HRV parameters in the current study cannot be entirely excluded, FMF patients in whom colchicine did not provide adequate symptomatic relief and who did not develop amyloidosis appear to have normal HRV parameters suggestive of normal ANS function, compared with healthy adults.