Sarcoidosis, an inflammatory granulomatous disease, is associated with various cardiac disorders, including threatening ventricular arrhythmias and sudden cardiac death. Heart rate recovery (HRR) 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 HRR in patients with sarcoidosis.
The study population included 56 patients with sarcoidosis (23 men, mean age = 47.3 ± 13.0 years, and mean disease duration = 38.4 ± 9.7 months) and 54 healthy control subjects (20 men, mean age = 46.5 ± 12.9 years). Basal ECG, echocardiography, and treadmill exercise testing were performed on all patients and control participants. The HRR index was defined as the reduction in the heart rate at peak exercise to the first-minute rate (HRR1), second-minute (HRR2), third-minute (HRR3), and fifth-minute (HRR5) after the cessation of exercise stress testing.
There are significant differences in HRR1 and HRR2 indices between patients with sarcoidosis and the control group (25 ± 6 vs 34 ± 11; P < .001 and 45 ± 10 vs 53 ± 12; P < .001, respectively). Similarly, HRR3 and HRR5 indices of the recovery period were lower in patients with sarcoidosis when compared with indices in the control group (53 ± 12 vs 61 ± 13; P < .001 and 60 ± 13 vs 68 ± 13; P < .001, respectively). Exercise capacity was notably lower (9.2 ± 2.1 vs 11.6 ± 2.8 METs; P = .001, respectively) and systolic pulmonary arterial pressure at rest was significantly higher in patients with sarcoidosis compared with the control group (29.7 ± 5.5 mm Hg vs 25.6 ± 5.7 mm Hg, P = .001, respectively). Furthermore, HRR indices were found to be different among radiographic stage groups.
The HRR index was impaired in patients with sarcoidosis as compared with control subjects. When the prognostic significance of the HRR index is considered, these results may partially explain the increased occurrence of arrhythmias and sudden cardiac death in patients with sarcoidosis. Our findings suggest that the HRR index may be clinically helpful in identifying high-risk patients with sarcoidosis.