Evaluation of various cardiac autonomic indices in patients with familial Mediterranean fever on colchicine treatment

Background: Familial Mediterranean fever (FMF) is characterized by sporadic, acute attacks of fever and serositis. Cardiovascular involvement is one of the leading cause of morbidity and mortality among FMF patients. Herein, we aimed to evaluate cardiac autonomic functions in FMF patients without overt cardiac symptoms. Methods: We enrolled 38 patients (20 female; mean age 34.4 ± 10.2 years) with FMF and 34 healthy subjects (18 female; mean age 33.2 ± 9.3 years). All participants underwent 24-hour Holter recording. Heart rate recovery (HRR) indices were calculated by subtracting first, second, and third minute heart rates from maximal heart rate. All patients underwent heart rate variability (HRV), heart rate turbulance (HRT) and QT dispersion analysis. The mean FMF duration was 9.8 ± 4.2 years. Results: Both groups were similar with regard to baseline characteristics. Mean HRR1 (p = 0.001), HRR2 (p = 0.003) and HRR3 (p<0.001) were significantly lower in FMF group. SDNN (standard deviation of all NN intervals), SDANN (SD of the 5. min mean RR intervals), RMSSD (root square of successive differences in RR interval), and PNN50 (proportion of differences in successive NN intervals > 50. ms) and high-frequency (HF) components were significantly decreased, but low frequency (LF) and LF/HF were significantly higher in FMF patients. HRT onset and slope were significantly less negative in FMF patients. Also, QTd was significantly higher in FMF patients (p < 0.001). Conclusion: Patients with FMF showed delayed recovery of heart rate and abnormal HRV and HRT parameters with respect to normal subjects. Cardiac autonomic functions might be involved in FMF patients even in patients without cardiac symptoms.