System of electrically measured physiological parameters for reconstruction of heart rate

The system of different electrically measured physiological parameters have been investigated to develop a model for heart rate reconstruction for rate adaptive pacing. There were three different parameters under examination: QT interval, ventilation volume and physical activity. The simultaneous non-invasive measurements of ECG, transthoracic impedance and physical activity for a group of healthy persons during different predetermined exercise tests and normal daily activities have been carried out. A special multichannel recording instrument has been developed for noninvasive registration of signals. Linear combination of QT and activity parameters gives a relatively simple, but satisfactory bases for heart rate reconstruction for rate adaptive cardiac pacing purposes. The developed model was tested with the group of persons and relative mean squared error between calculated and natural heart rate for the group turned to be 8.4%.