The effect of respiration-induced heart movements on the ECG.

We present a model describing the rotation of the cardiac vector as a possible mechanism resulting in the presence of respiratory information in the ECG. The way in which this information is revealed is analyzed and the predictions subjected to qualitative experimental assessment via spectral analysis. The results show that respiratory frequencies occur in the ECG spectrum due to heart movement. By measuring on a patient wearing a pacemaker and ventilated to control respiratory rate we show that even in the absence of respiratory sinus arrhythmia (RSA) there is a baseband information in the ECG spectrum, attributable neither to electrode artifacts nor to emg, and sidebands from the respiratory cycle.