Beat-to-beat variation of the heart rate in children with allergic asthma.

Beat-to-beat variation of the heart rate in 53 allergic asthmatic children was quantitatively measured as a coefficient of variation of the R-R interval (CVR-R), and was compared with that of 284 nonallergic and 47 allergic children without asthma. Allergic children both with and without asthma had significantly higher mean CVR-R values (7.08 +/- 1.87 and 7.54 +/- 2.40 and p less than 0.01 and p less than 0.001, respectively) than those of non-allergic children (6.32 +/- 1.88). These results confirm the previous reports that the increased cholinergic tone was related to the allergic state and not only to allergic asthma.