Median Frequencies of Prolonged Ventricular Fibrillation treated by V-A ECMO Correspond to a Return of Spontaneous Circulation Rate

Abstract

Background The aim of our study was to analyze, in a pig model of prolonged ventricular fibrillation (VF) treated by veno-arterial extracorporeal membrane oxygenation (ECMO), the time dependent changes of VF wavelet frequency obtained from intracardial signals and its relations to return of spontaneous circulation (ROSC). Methods 11 female pigs (50.3 ± 3.4 kg) under general anesthesia had undergone 15 min of VF with ECMO flow of 5 to 10 ml/kg per min simulating “untreated” VF followed by continued VF with full ECMO flow of 100 ml/kg per min. The median frequency (MF) of VF from right ventricular apex, coronary perfusion pressure, myocardial oxygen metabolism and resuscitability were determined. Results Median (interquartile range) of MF of fibrillatory wavelets in minute 15 of low ECMO flow [9.7 Hz (8.3; 10.1)] was not significantly changed in comparison to minute 1 [10.5 Hz (9.8; 12.4)], p = 0.12. Five minutes after full ECMO initiation MF increased [11.6 Hz (10.6; 13.5)], p = 0.04 (compared to minute 15 of VF) and did not deteriorate during the rest of ECMO treatment. Out of all subjects, three animals did not reach ROSC. Those subjects demonstrated deeper decrease of MF at the VF minute 15 as compared to others [-2.4 Hz (-2.5; −2.3) vs. −0.6 Hz (-1.6; −0.1)] and continuously significantly higher increase in MF on full ECMO support [4.3 Hz (2.9; 5.6) vs. 1.1 Hz (0.6; 1.6)] with p = 0.05 for both observations, respectively. Conclusions The veno-arterial ECMO reperfusion influences MF of VF wavelet obtained from right ventricular apex. The course of changes in wavelet frequency corresponds to a presence of later ROSC.

Inducibility of ventricular fibrillation during mild therapeutic hypothermia: electrophysiological study in a swine model

“…Thus, the translation of the results to humans should be interpreted with caution despite the fact, that our biomodel was represented by a breed repeatedly validated for simulation of human cardiac arrest and resuscitation [46,47]. The number of experimental animals tested is low, however multiple pairwise comparisons in individual animals counterbalances this limitation.…”

Renal denervation decreases effective refractory period but not inducibility of ventricular fibrillation in a healthy porcine biomodel: a case control study

“…Also the number of tested experimental animals was low and the electrophysiological study was not performed in the same biomodel before and after RDN because of presumed high morbidity-mortality of biomodels during the 40-day period after the procedure. Thus, the translation of the results to humans should be interpreted with caution despite the fact, that our biomodels were represented by a breed repeatedly validated for simulation of human cardiac arrest and evaluation of VF [ 27 , 28 ].…”