Respiratory signal derived from eight-lead ECG

Several techniques are actually used for respiratory monitoring (spirometers, nasal thermocouples, transthoracic inductance, impedence plethysmography, strain gauge). Each of these techniques require a special device. The method here proposed derives the EDR values (ECG-Derived-Respiratory signal) from ordinary ECGs. Eight ECG leads are utilized. The method is based on the verified hypothesis that the breath-representative "points" are disposed around the preferred direction in a 8-D space. Once the "respiratory direction" is located, the method produces the EDR values. The respiratory waveform is obtained through an interpolation of such values. The method has been tested on 10 voluntary subjects in different conditions (deep breath, short breath, held breath to simulate apnea). The EDR trace obtained has been compared with a reference signal acquired from strain gauge measurement of thoracic circumference. This technique is applicable to any type of automated ECG analysis, in real-time and without the need for additional transducers or hardware.