Electrocardiogram frequency change by extracorporeal blood perfusion in a swine ventricular fibrillation model

Abstract

Background : Extracorporeal cardiopulmonary resuscitation (ECPR) refers to the application of extracorporeal blood circulation with oxygenation as a resuscitation tool. The objective of this study is to observe the frequency component changes in the electrocardiogram (ECG) by ECPR during prolonged ventricular fibrillation (VF). Methods : Six swine were prepared as a VF model. Extracorporeal blood circulation with a pulsatile blood pump and oxygenator was set up for the model. ECG signals were measured for 13min during VF and analyzed using frequency analysis methods. The median frequency (MF), dominant frequency (DF), and amplitude spectrum area (AMSA) were calculated from a spectrogram obtained using short-time Fourier transform (STFT).

Results : MF decreased from 11Hz at the start to 9Hz at 2min after VF and then increased to 11Hz at 4.5min after VF. DF started at 7Hz and increased to 11Hz within the first min and decreased to 9Hz at 2min, then increased to 12Hz at 4.5min after VF. Both frequency components decreased gradually from 4.5min until 10min after VF. After the oxygenated blood perfusion was initiated, both MF and DF increased remarkably and exceeded 12 and 14Hz, respectively. Similarly, AMSA decreased gradually for the first 10min, but increased remarkably and varied beyond 13mV∙Hz after the oxygenated blood supply started. Remarkable frequency increases in ECG due to the oxygenated blood perfusion during ECPR were observed in the swine VF model.

Conclusions : The ECG frequency analysis during ECPR can give the resuscitation provider important information about the cardiac perfusion status and the appropriateness of the ECPR setup as well as the prediction of defibrillation success.