Fifteen patients diagnosed with bronchial asthma were examined to evaluate the cardiotoxicity caused by the combined intravenous treatment using methylxanthine-aminophylline 250 mg and a beta agonist: salbutamol 0.5 mg. The following observations were made: four patients had sinus tachycardia and another suffered from ventricular extrasystoles as seen in the electrocardiographic register; another two patients had sinus tachycardia when the bronchial dilator dosage was doubled. From a clinical and electrocardiographic standpoint, arrhythmias do not seem to be a grave problem among the population studied.