Utility of the Ventricular Fibrillation Waveform to Predict a Return of Spontaneous Circulation and Distinguish Acute From Post Myocardial Infarction or Normal Swine in Ventricular Fibrillation Cardiac Arrest

Abstract

Background-In cardiac arrest, the ventricular fibrillation (VF) waveform, particularly amplitude spectral area (AMSA) and slope, predicts the return of spontaneous circulation (ROSC), but it is unknown whether the predictive utility differs in an acute myocardial infarction (MI), prior MI, or normal myocardium and if the waveform can distinguish the underlying myocardial state. We hypothesized that in a swine model of VF cardiac arrest, AMSA and slope predict ROSC after a shock independent of substrate and distinguish an acute from nonacute MI state. Methods and Results-MI was induced by occlusion of the left anterior descending artery. Post MI swine recovered for a 2-week period before induction of VF. VF was untreated for 8 minutes in 10 acute MI, 10 post MI, and 10 control swine. AMSA and slope predicted ROSC after a shock independent of myocardial state. For AMSA Ͼ31 mV-Hz, the odds ratio was 62 (PՅ0.001) compared with AMSA Ͻ19 mV-Hz. For slope Ͼ3.1 mV/s, odds ratio was 52 (PՅ0.001) compared with slope Ͻ1.8 mV/s. With chest compressions, AMSA and slope were significantly lower for acute MI swine compared with control swine, whereas in post MI swine the waveform characteristics were similar to control swine. In particular, for an AMSA Ͼ33.5 mV-Hz, the sensitivity to identify an acute from nonacute (control or post MI) state was 83%. Conclusions-In a swine model of VF cardiac arrest, AMSA and slope predict ROSC independent of myocardial substrate.Furthermore, with chest compressions, the VF waveform evolves differently and may offer a means to distinguish an acute MI. (Circ Arrhythm Electrophysiol. 2011;4:337-343.)

Amplitude Spectrum Area to Guide Defibrillation

“…12 Indeed, evidence exists for ventricular fibrillation (VF) waveform changes over time, which might enable prediction of the success of a defibrillation attempt. 4,[12][13][14][15][16][17] Small clinical studies have demonstrated that amplitude spectrum area (AMSA) is one of the most accurate predictors of defibrillation success. 16,17 However, none of these studies reported any patients'…”

Characteristics of ventricular fibrillation in relation to cardiac aetiology and shock success: A waveform analysis study in ICD-patients

“…In addition, it was observed that the number of activation wave fronts was smaller than in controls, both over the infarcted and over the normal tissue of the dogs with a previous MI 17 . In the presence of an acute MI, differences in VF waveform characteristics as compared with controls may even become more apparent 10,19,20 .…”

Amplitude-spectral area and chest compression release velocity independently predict hospital discharge and good neurological outcome in ventricular fibrillation out-of-hospital cardiac arrest

“…The primary purpose of this investigation was to determine whether the VF waveform, as measured by AMSA, can predict resuscitation outcome independent of CC quality, since chest compressions are known to raise AMSA 15,16,17,18,19 . We find that the waveform parameter AMSA-avg was a very strong and independent predictor of both hospital discharge and good neurological outcome, with survival clustered at higher values of AMSA-avg (Fig.…”

“…It is known that AMSA rises with well-performed chest compressions in both animal 15,16,17 and human studies 18,19 . This raises the question whether it is solely chest compression quality that predicts outcome or whether the VF waveform can add independent predictive value.…”