Salbutamol inhalation has no effect on myocardial ischaemia, arrhythmias and heart-rate variability in patients with coronary artery disease plus asthma or chronic obstructive pulmonary disease.

Abstract

Inhaled beta-2 agonists raise heart rate, systolic blood pressure and contractility, all of which cause an increase in oxygen consumption of the heart. We performed a study on the influence of inhaled salbutamol on myocardial ischaemia, rhythm, and heart rate variability as assessed by Holter monitoring of 24 patients with coronary artery disease (CAD) and clinically stable asthma or chronic obstructive pulmonary disease (COPD). In hospital the patients received 0.2 mg (hour 1), 0.4 mg (hour 6), 0.8 mg (hour 13) of salbutamol with a metered-dose inhaler and a spacer, and 5 mg (hour 25) with a nebulizer; symptoms, peak expiratory flow (PEF), 30-h Holter monitoring, and blood pressure (BP) were recorded. The study parameters were compared for the hour preceding and following each dose of salbutamol. No cardiac symptoms were associated with salbutamol inhalation. PEF increased after all doses (P < 0.005). A dose of 0.2 mg salbutamol induced no changes in heart rate, whereas dose of 0.4 mg increased heart rate from a mean of 75 +/- 13 to 79 +/- 14 beats min-1 (P < 0.005), and a dose of 0.8 mg from 76 +/- 14 to 78 +/- 15 beats min-1 (P < 0.05). No changes in systolic BP appeared after any dose of salbutamol. The diastolic BP was lowered after 0.8 mg of salbutamol from 86 +/- 12 to 82 +/- 10 mmHg (P < 0.05). The 5 mg of nebulized drug provoked no significant changes in heart rate or BP. Myocardial ischaemia, heart rate variability and ventricular arrhythmias remained unaltered with all doses. The commonly used doses of inhaled or nebulized salbutamol induced no acute myocardial ischaemia, arrhythmias or changes in heart rate variability in patients with CAD and clinically stable asthma or COPD.