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Background: Arsenic exposure is associated with various cardiovascular diseases. The aim of the present study was to assess cardiac autonomic function via heart rate response to exercise and recovery period of treadmill testing in arsenic-exposed workers., Methods: Sixty-five (65) occupationally arsenic-exposed workers and 35 healthy controls were enrolled. Blood and urinary arsenic levels were analyzed and symptom limited maximal treadmill exercise test were performed. Chronotropic response to exercise including age-predicted maximal heart rate (APMHR), heart rate reserve (HR reserve ), age-predicted HR reserve (APHR reserve ) and adjusted HR reserve and 1st-, 2nd-and 3rd-min heart rate recovery (HRR) indices were calculated., Results: Baseline clinical and echocardiographic parameters, exercise test duration, resting and maximal heart rate, peak exercise capacity, HR reserve , APMHR, APHR reserve , and adjusted HR reserve were found to be similar between groups. HRR 1 (22.0 ± 4.3 vs. 24.3 ± 3.1 bpm, p = .003) and HRR 2 (43.2 ± 6.2 vs. 46.7 ± 6.4 bpm, p = .012) were significantly lower in arsenic-exposed workers compared to controls. Blood and urinary arsenic levels negatively correlated with HRR 1 (r = -.477, p < .001 and r = -.438, p < .001, respectively) and HRR 2 (r = -.507, p < .001 and r = -.412, p < .001 respectively)., Conclusions: Arsenic-exposed workers had lower HRR indices than normal subjects but chronotropic response were similar. Cardiac autonomic dysregulation may be one of the cardiovascular consequences of arsenic exposure., (© 2017 Wiley Periodicals, Inc.)

Background: To evaluate electrocardiographic parameters which are related with atrial and ventricular arrhythmias measured from 12-lead surface electrocardiogram (ECG) in workers occupationally exposed to lead., Methods: Sixty lead-exposed workers and 60 healthy controls were enrolled. Twelve-lead surface ECG was recorded and measurements of P wave durations (Pmax, Pmin) and P wave dispersion (PWD), QT durations and dispersion (QTd), corrected QT (QTc), Tp-e interval, and Tp-e/QT ratio were analyzed., Results: The lead-exposed and control groups were similar with respect to baseline demographic, laboratory, and transthoracic echocardiographic indices. PWD (26.3 ± 9.7 vs 22.0 ± 9.0 ms, P = 0.014), Pmin (89.9 ± 13.8 vs 79.2 ± 10.1 ms, P < 0.001), and Pmax (116.2 ± 15.0 vs 101.2 ± 14.2 ms, P < 0.001), QT maximum (377.0 ± 27.6 vs 364.9 ± 28.5 ms, P = 0.02), QTd (38.4 ± 16.5 vs 30.5 ± 12.4 ms, P = 0.004), Tp-e interval (78.9 ± 16.5 vs 70.3 ± 14.5 ms, P = 0.003), and Tp-e/QT ratio (0.22 ± 0.04 vs 0.20 ± 0.04, P = 0.013) were significantly higher in lead-exposed workers. QT minimum and QTc values did not differ significantly. QT maximum, QTd, and Tp-e/QT ratio were correlated with urine lead level and Tp-e interval was correlated with both blood and urine lead levels., Conclusions: Lead-exposed workers have a higher risk for atrial and ventricular arrhythmias even without overt cardiac diseases compared with healthy subjects. These workers should be followed closely for adverse cardiovascular outcomes especially arrhythmias., (© 2016 Wiley Periodicals, Inc.)