Abstract P77: Chest Compression After Defibrillation May Reinduce Ventricular Fibrillation as in Commotion Cordis Cardiac Arrest
Recurrence of ventricular fibrillation (VF) during out-of-hospital cardiac arrest is a frequent event described during resuscitation attempt. Hypothesis. We assessed the hypothesis that chest compression performed during a spontaneous electrical activity (SEA) may induce recurrent VF (rVF) after the first successful shock.
Methods. This is a retrospective study of out-of-hospital cardiac arrest recorded in the city of Piacenza, Italy, where a lay responders project of early defibrillation called “Progetto Vita” was organized. rVF were identified by analyzing the available ECGs from the automated external defibrillators. All analysis were supported by voice recorded during interventions. Successful shock was defined as cases in which VF was interrupted for at least 5 seconds. Rhythms after shock were categorized as
asystolia (amplitude <100 μV) and
SEA, when ventricular or atrial activity were present in the 5 seconds post shock.
Chest compression was assessed for association with rVF during either asystole or SEA.
Results. 160 consecutive pts with available and good quality ECG were considered for the analysis of rVF. 102/160 pts had rVF (63,75%). The total of rVF were 321. 208/321 rVF (64.8%) were related to chest compression while 112/321 (35.2%) were spontaneous (R/T phenomenon). Before chest compression-rVF a spontaneous electrical activity was present in 153/208 episodes (73,6%) while asystolia was present in only 55/208 episodes (26.4%). Among 112 spontaneous episodes of rVF 88/112 (78.5%) occurred during SEA while 24/112 (21.4%) occurred during asystolia.
Conclusion. Chest compression may be the trigger of rVF when precordial impacts is timed to occur during a vulnerable point in the cardiac cycle as demonstrated for commotion cordis induction of ventricular fibrillation. The potential benefit of chest compression, in term of oxygen supply, can be blunted by the reinduction of VF. After shock the restoration of a spontaneous electrical rhythm should delay chest compression.