Background: Arrhythmias, conduction disturbances, and cardiac autonomic nervous system dysfunction are the most frequent cardiovascular complications in systemic sclerosis (scleroderma). The aim of the study was to assess heart rate turbulence (HRT) in systemic sclerosis patients and to identify the relationship between HRT and occurrence of arrhythmias.
Methods: Forty-five patients with scleroderma (aged 54.6 +/- 14.7 years) and 30 healthy sex- and age-matched subjects were examined. In addition to routine studies, 24-hour Holter monitoring with assessment of HRT was performed.
Results: As compared to controls, HRT was significantly impaired in systemic sclerosis patients. Abnormal HRT defined as turbulence onset (TO) > or =0.0% and/or turbulence slope (TS) < or =2.5 ms/RR (ms/RR interval) was found in 19 (42%) scleroderma patients and in no members of the control group. Serious ventricular arrhythmias Lown class IV (VA-LownIV), for example, couplets and/or nonsustained ventricular tachycardias, were observed in 16 (36%) scleroderma patients. The median value of TS was significantly lower in systemic sclerosis patients with VA-LownIV than in patients without VA-LownIV (3.68 vs 7.00 ms/RR, P = 0.02). The area under curve of ROC analysis for prediction of VA-LownIV was 0.72 (95% confidence interval [CI] 0.56-0.87) and revealed that TS <9.0 ms/RR was associated with VA-Lown IV occurrence, with sensitivity of 93.7% and specificity of 44.8%. Univariate and multivariate analyses confirmed that lower values of TS were associated with VA-LownIV occurrence (odds ratio 1.52, 95% CI 1.09-2.12, P = 0.01).
Conclusions: Patients with systemic sclerosis are characterized by significant HRT impairment. Assessment of HRT and especially TS is useful in the identification of patients at risk for ventricular arrhythmias.