Background: Autonomic dysfunction in patients with chronic obstructive pulmonary disease (COPD) may increase\nthe risks of arrhythmia and sudden death. We studied cardiac autonomic function in patients with acute\nexacerbation of COPD (AECOPD).\nMethods: Patients with AECOPD were classified into ventricular tachycardia (VT) and non-VT groups according to\nthe presence or absence of VT. The following parameters derived from 24-h Holter monitoring were compared\nbetween groups: average heart rate, heart rate deceleration capacity (DC), heart rate acceleration capacity (AC),\nstandard deviation of normal RR intervals (SDNN), standard deviation of average RR interval in 5-min segments\n(SDANN), root mean square of standard deviations of differences between adjacent normal RR intervals (rMSSD),\nlow-frequency power (LF), high-frequency power (HF) and LF/HF ratio.\nResults: Seventy patients were included, 22 in the VT group and 48 in the non-VT group. The groups had similar\nclinical characteristics (except for more common amiodarone use in the VT group, P < 0.05) and general ECG\ncharacteristics. DC, SDNN, SDANN and rMSSD were lower and AC higher in the VT group (P < 0.05). In the VT group,\nDC was correlated positively with SDNN (r = 0.716), SDANN (r = 0.595), rMSSD (r = 0.571) and HF (r = 0.486), and\nnegatively with LF (r = -0.518) and LF/HF (r = -0.458) (P < 0.05). AC was correlated negatively with SDNN (r = -0.682),\nSDANN (r = -0.567) and rMSSD (r = -0.548) (P < 0.05).\nConclusions: DC decreased and AC increased in patients with AECOPD and VT, reflecting an imbalance in\nautonomic regulation of the heart that might increase the risk of sudden death.
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