Swapna Ramaswamy, Sunil K Chhabra*, Mansi Gupta, Devi Jyoti Dash and Vishal Bansal Pages 166 - 171 ( 6 )
Background: A shift of cardiac autonomic balance towards sympathetic marks a poor prognosis in several diseases and has also been reported in COPD. Bronchodilators, beta-2 adrenergic agonists and anticholinergic drugs, are the mainstay of treatment of COPD. We hypothesized that drugs belonging to these classes, respectively salbutamol and ipratropium, would cause a sympathetic shift in cardiac autonomic activity as a consequence of their pharmacological actions.
Objective: To study the effect of ipratropium and salbutamol on Heart Rate variability in COPD.
Methods: Thirty-three stable ex-smoker, inpatient-male COPD patients were included in a doubleblind, placebo-controlled single-dose randomized study. After baseline spirometry, cardiac autonomic activity was measured using Heart Rate Variability (HRV) that yields several measures of parasympathetic and sympathetic activity. The patients randomly received placebo, salbutamol (200μg) or ipratropium (80µg) by inhalation on three consecutive days. After half an hour, HRV measurements and spirometry were repeated. The average heart rate, and various time and frequency domain parameters were obtained using non-parametric Fast Fourier Transform (FFT) algorithm.
Results: Ipratropium decreased the resting heart rate by 2.5% while salbutamol increases it by approximately 6%. Salbutamol resulted in a significant decrease in normalized high frequency variability (HFnu), a marker of parasympathetic activity, and increase in normalized low frequency variability (LFnu) that marks sympathetic activity, and the LF/HF ratio indicating a sympathetic shift of autonomic balance. Ipratropium had no effect on HRV parameters. The study shows that a single inhalation of 200 µg salbutamol shifts cardiac autonomic control towards increased sympathetic activity whereas ipratropium does not.
Conclusion: Inhalation of salbutamol causes a sympathetic shift in the cardiac autonomic balance.
Cardiac autonomic dysfunction, chronic obstructive pulmonary disease, heart rate variability, ipratropium, salbutamol.
Department of Pulmonary Medicine, University of Delhi, Delhi - 110 007, Department of Pulmonary Medicine, University of Delhi, Delhi - 110 007, Department of Pulmonary Medicine, University of Delhi, Delhi - 110 007, Department of Pulmonary Medicine, University of Delhi, Delhi - 110 007, Physiology, Vallabhbhai Patel Chest Institute, University of Delhi, Delhi - 110 007