Evaluation of cardiovascular autonomic dysfunction in children with familial Mediterranean fever

Evaluation of cardiovascular autonomic dysfunction in children with familial Mediterranean fever Background: Familial Mediterranean fever (FMF) is an autosomal resesive autoinflammatory disease, which is characterized by recurrent fever and serositis. Cardiovascular involvement is one of the important reasons of mortality and morbity in FMF. There are studies showing the impression of cardiovascular autonomic functions in adult FMF patients in the literature. This study aimed to evaluate the cardiac autonomic functions in children with FMF by using different autonomic tests. Patients and methods: Thirty-five FMF patients without amyloidosis aged between 6-17 were enrolled in the study. Thirty-five age- and sex-maaged healthy children constituted the control group. Electrocardiography, echocardiography, epicardiyal fat tissue thickness, hear rate recovery (HRR1-5) index during the first five minutes after the cessation of exercise stres testing, heart rate variability parameters (SDNN, SDNNi, SDANN, RMSSD, mean RR) measured by 24-hour Holter EKG, QTc / QTd analysis and Tilt-table test were assessed. Results: The mean age of FMF patients (18 male, 17 female) was 11.6±3.5 years. Fractal dimension analysis showed that diastolic tension parameters were significantly lower in patients than healthy controls (p: 0.01). one of the heart rate variability parameter, mean RR was significantly lower in patients with FMF than controls (p: 0.02). There was a significant negative corelation between number of FMF attacks and RMSSD value (r:-0.342, p:0.04). Besides, There was a significant positive corelation between number of FMF attacks and QTC extension (r:0.360, p:0.03). Heart rate recovery parametres were negatively corelated with number of attacks, disease severity score, dose of colchicine, and cumulative colchicine dose. Chronotropic responses to exercise test were positively corelated with number of attacks and disease severity score. A significant negative corelation was detected between epicardial fat tissue thickness and both post-exercise hearty rate recovery indexes and RMSSD. There was not a significant corelation between the vasovagal reaction and disease duration, disease severity score, and colchicine treatment. However, FMF patients with exertional leg pain had significantly higher vasovagal reaction rates than the patients without (p:0.01). Conclusion: The results of this study suggested that subclinical autonomic function impression was started even in childhood in FMF patients. The existence of cardiovascular autonomic dysfunction was shown to be related to some factors such as, disease duration, disease severity, number of attacks and colchicine use.