Deglutition-induced tachycardia and spectral analysis of the heart rate

In healthy subjects at rest, swallowing is accompanied by a tachycardiac or tachycardiac-bradycardiac reaction, during which the heart rate can be accelerated by as much as 20 beats/min. The duration of these reactions is comparable to the period of regular low-frequency heart rate oscillations, thereby their occurrence during ECG recordings for heart rate spectral analysis leads to overestimation of low-frequency oscillation power. Using a special method of smoothing of single tachycardia waves, we found that in young healthy subjects the mean contribution of deglutition-induced tachycardia waves to the power of low-frequency heart rate oscillations is 42%.