Heart Rate Monitoring Using Electrical Impedance

Monitoring tissue composition could be persistent for many medical applications. Bioimpedance may be useful for monitoring several cardiovascular parameters such as cardiac output, stroke volume, blood pressure and heart rate. In addition, it could be useful for diagnosing the mitral insufficiency, stenosis, and other valvular heart diseases. The purpose of this study is to use the bioimpedance signal to determine the heart rate. This study involved 51 volunteers (28 male, 23 female) ranging from 20 to76 years. A current of 1 mA at 30 kHz was injected through two outer electrodes placed on the subject's left arm and then the impedance was collected using two inner electrodes placed between the former outer electrodes. The acquired bioimpedance signal was pre-processed and used to identify the peaks and calculated the average interval. Thus, heart rates of each subject were calculated and then compared with actual measurement from FUZZY model MP3 digital blood pressure monitor. The results showed high correlation, 95.44 %, between the calculated heart rates and measurements. The various clinical applications of bioimpedance will help further promote the technique and several parameters can be determined using the electrical bioimpedance approach.