[Cardiac tolerance of a beta-2-sympathomimetic spray: fenoterol. Apropos of 37 patients followed using a Holter monitor during a brief treatment protocol].
37 subjects with stable asthma and a mean age of 50.3 undertook a protocol to study the cardiac tolerance to a spray B2SM. A Holter monitor was performed before and 48 hours after the institution of a Fenoterol spray in 4 daily doses of 600 micrograms at fixed times. Before starting treatment with a beta 2 sympathomimetic spray (B2SM) 11 subjects had abnormal traces with significant auricular extra-systoles in 4, ventricular extra-systoles in 5 and both in one subject: one patient had a run of ventricular tachycardia without symptoms. On Fenoterol, a worsening of pre-existing extra systoles was noted thrice, one was auricular the other two ventricular. Two patients had brief runs of ventricular tachycardia but the role of Fenoterol was uncertain; one of the patients was very elderly and hypoxaemic. In the second and elevated theophylline level of 20 micrograms/l was noted. The arrythmogenic power of a B2SM seems weak, but in certain situations such as hypoxaemia, metabolic acidosis and overdosage of theophylline, over consumption of B2SM in association with the above factors could contribute to serious arrhythmias. Also in this study in which there was a protocol limited in time, no premature conclusion should be made on the crucial problem of the cardiovascular risks of B2SM in the basic treatment of asthma but raises the problem of the arrythmogenic potential of the drug association of Theophylline + B2SM.