Abstract P141: Electrocardiogram Waveform Analysis Reveals Probability of Return of Spontaneous Circulation in Both Swine and Human Subjects

Abstract

Background: The Logarithm of the Absolute Correlations (LAC) is a measure which estimates VF duration based on the fractal dimension of the waveform. We hypothesized that the LAC measures the underlying physiology of the myocardium and would enable identification of those who would have return of spontaneous circulation (ROSC) in response to the initial shock. We tested this hypothesis in a swine model and among humans treated for out-of-hospital cardiac arrest Methods: 20 swine were placed in VF either by electrical stimulation (n=10) or through ischemia produced by percutaneous balloon occlusion of the left anterior descending artery (n=10). After 7 minutes of VF, CPR was performed for 1 min followed by defibrillation. Response to shock was recorded as ROSC if a BP of 60 mm Hg was present. The LAC was calculated for five second intervals during VF. In the human cohort, the AED ECG recordings of 165 subjects were analyzed. The average interval from 9 –1–1 call to EMS scene arrival was 5 minutes. Response to shock was recorded as ROSC if an organized rhythm corresponded with a palpable BP as determined by review of audio and written EMS report. The LAC was calculated on the 6 seconds of VF preceding the initial shock. In both the swine and human experience, we compared the mean LAC between those with and without ROSC. We calculated receiver operating characteristic (ROC) curves and measured the area under the curve to assess the diagnostic ability of the LAC. Results: In the swine model, the mean LAC differed significantly between swine with and without ROSC following the initial shock (with ROSC: 5.17±0.19 [n=6] versus without ROSC: 4.88±0.27 [n=14]: p = 0.033). The AUC for the LAC measure was 0.80. In the human cohort, the LAC also differed significantly between those with and without ROSC following the initial shock (5.21±0.34 [n=36] versus 4.81±0.47 [n=129], p < 0.0001). The AUC for the LAC measure was 0.76. Conclusions: The LAC measure predicts ROSC in both swine and human VF and can be used to guide resuscitation care. Swine ischemic VF is similar to that seen in humans.