Assessment of heart rate recovery index in patients with familial Mediterranean fever

Abstract

Heart rate recovery after exercise is a function of vagal reactivation, and its impairment is an independent prognostic indicator for cardiovascular and all-cause mortality. The aim of our study was to evaluate heart rate recovery in patients with familial Mediterranean fever (FMF). The study population included 38 patients with FMF (14 men; mean age, 36.2 ± 12.1 years, and mean disease duration = 11.3 ± 6.5 years) and 35 healthy control subjects (12 men; mean age = 34.1 ± 9.9 years). Basal electrocardiography, echocardiography, and treadmill exercise testing were performed in all patients and control participants. The heart rate recovery index was defined as the reduction in the heart rate from the rate at peak exercise to the rate 1st-minute (HRR(1)), 2nd-minute (HRR(2)), 3rd-minute (HRR(3)), and 5th-minute (HRR(5)) after the cessation of exercise stress testing. There are significant differences in HRR(1) and HRR(2) indices between patients with FMF and control group (26.4 ± 7.4 vs. 35.0 ± 8.0; P = 0.001 and 47.3 ± 11.8 vs. 54.8 ± 10.3; P = 0.002, respectively). Similarly, HRR(3) and HRR(5) indices of the recovery period were lower in patients with FMF, when compared with indices in the control group (56.0 ± 14.0 vs. 63.7 ± 11.2; P = 0.01 and 64.1 ± 14.7 vs. 71.5 ± 12.7; P = 0.02, respectively). There were also remarkably positive correlations between the disease duration and HRR(1) (r = 0.31, P = 0.02), and HRR(2) (r = 0.26, P = 0.04). The heart rate recovery index impaired in patients with FMF compared to control subjects. When the prognostic significance of the heart rate recovery index is considered, a useful, simple, and noninvasive test may be clinically helpful in the recognition of high-risk patients with FMF.