Assessment of Cardiac Autonomic Nervous System Involvement in Systemic Sclerosis via Exercise Heart Rate Recovery

OBJECTIVE: To assess exercise heart rate recovery (HRR) indices in patients with systemic sclerosis (SSc) for an assessment of their cardiac autonomic function. SUBJECTS AND METHODS: Thirty-five patients with diffuse or limited SSc and 35 healthy controls were enrolled. All subjects underwent exercise testing and transthoracic echocardiography. The HRR indices were calculated by subtracting the first- (HRR1), second- (HRR2) and third-minute (HRR3) heart rates from the maximal heart rate. RESULTS: The SSc and control groups were similar in age (45.2 ± 11.6 vs. 43.9 ± 10.0 years), had identical gender ratios (31 female/4 male in both groups) and similar left ventricular ejection fraction (66.5 ± 5.1 vs. 67.7 ± 5.9%). The mean HRR1 (21.8 ± 4.4 vs. 27.7 ± 4.3 bpm, p = 0.001), HRR2 (43.8 ± 6.3 vs. 47.6 ± 4.4 bpm, p = 0.004) and HRR3 (58.8 ± 10.3 vs. 63.6 ± 7.3 bpm, p = 0.031) values were significantly lower in the SSc group than in the healthy controls. HRR indices were similar in the limited and diffuse SSc subgroups. CONCLUSIONS: The patients with SSc had lower HRR indices than normal subjects. Cardiac autonomic functions might be involved in SSc, even in patients without cardiac symptoms.