Abstract 19221: Inter Shock Changes of the Ventricular Fibrillation Waveform in Relation to Return of Spontaneous Circulation: Amplitude or Frequency Driven?
Introduction: Recent studies on ventricular fibrillation (VF) waveform characteristics described that an increasing amplitude spectrum area (AMSA) is associated with return of spontaneous circulation (ROSC). However, by using only the AMSA as a measure of the VF waveform, it remains unclear if either amplitude or frequency changes are more important for ROSC. In this light, we aimed to investigate the contribution of both components in relation to ROSC.
Methods: Retrospective analysis on a cohort of 598 out-of-hospital cardiac arrest patients in the region of Nijmegen, The Netherlands (2008-2011). We studied patients with VF as first observed rhythm, who received ≥2 shocks. Prior to the first two shock deliveries, the AMSA, mean amplitude and median frequency were calculated from 3-second VF-recordings. The ratios of these metrics between the first two shocks were analyzed for the endpoint ROSC at hospital transportation.
Results: Ninety-eight patients were analyzed, of whom 39% (38/98) had ROSC at hospital transportation. Prior to the first shock delivery, AMSA and mean amplitude were higher in patients with ROSC as compared to patients without ROSC. Prior to the second shock, all VF characteristics were higher in the ROSC group. Regarding waveform changes between shock 1 and shock 2, higher ratios of AMSA were associated with ROSC. Higher ratios of median frequency were associated with ROSC, whereas changes in amplitude did not differ between the study groups.
Conclusions: Both amplitude and frequency dependent characteristics of the VF waveform prior to shock deliveries are higher in patients who achieve ROSC. Whereas both patient groups show increasing amplitudes between the first two shocks, increases in frequency content were only found in patients with ROSC. These findings implicate that frequency changes rather than amplitude changes are most important for outcome after a resuscitation based on VF.
Author Disclosures: J. Thannhauser: None. J. Nas: None. J.L. Bonnes: None. G. Meinsma: None. P.M. van Grunsven: None. J.L. Smeets: None. M.J. de Boer: Consultant/Advisory Board; Modest; member of the european advisory board on interventional cardiology of Medtronic. M.A. Brouwer: None.
- © 2016 by American Heart Association, Inc.