Altered cardiovascular autonomic regulation after salmeterol treatment in asthmatic children

The effects of therapeutic 4 weeks' inhaled salmeterol treatment on the cardiovascular and respiratory autonomic nervous regulation was studied in 11 asthmatic children using inhaled corticosteroid medication. The study followed a randomized, double-blind, placebo-controlled cross-over design. The salmeterol dose was 50 μg twice daily. The 4-week salmeterol treatment increased baseline heart rate, low-frequency/high-frequency (LF/HF) variability ratio of R–R intervals, LF variability of systolic arterial pressure (SAP) and maximum tidal volume during the deep breathing test, as well as morning and evening peak expiratory flow (PEF) values. The 4-week salmeterol treatment decreased baseline HF variability of R–R intervals. As a response to the acute 600 μg of salbutamol, the changes in heart rate, HF variability of R–R intervals and diastolic blood pressure were significantly smaller after 4 weeks' salmeterol treatment. In conclusion, 4 weeks' therapeutic salmeterol treatment decreases basal cardiovagal reactivity, increases sympathetic dominance in the cardiovascular autonomic balance and improves pulmonary function. A tolerance develops in the cardiovascular response but not in the bronchodilatory response.