Abstract P16: The Decreases of Left Ventricle Volume and Area During VF Affect Resuscitation Outcomes

Abstract

Introduction: Dynamic changes in dimensions of left ventricle (LV) during cardiac arrest might influence the efficacy of CPR. However, the relationships between change in LV dimensions during cardiac arrest and CPR hemodynamic and outcomes remain to be studied. In the present study, we investigated changes of left ventricular volume and area during prolonged untreated ventricular fibrillation (VF) and related those change to coronary perfusion pressure (CPP) during CPR and resuscitation outcomes. Hypothesis: Decreased LV volume and area during prolonged VF interval would yield low CPP and poor resuscitation outcomes. Methods: In 12 domestic male pigs weighing 40±3 kg, VF was electrically induced and untreated for 15 min. CPR was performed for a 5 min interval prior to defibrillation. CPR was continued until return of spontaneous circulation (ROSC) or for a max of 15 minutes. Diastolic aortic and right atrial pressures were measured and CPP was calculated. LV dimensions were continuously assessed by echocardiographic measurement during the 15 minutes of untreated VF. Results: 6 animals were successfully resuscitated. During the 15 minute interval of VF, LV area and volume reduced in all the animals. In animals that were not resuscitated LV dimensions were significantly lower compared to those in resuscitated animals (p=0.01). These differences were observed after 10 minutes of untreated VF. The animals with greater reduction in LV dimension during VF, achieved significantly lower CPP during CPR in contrast to animals with larger LV during VF (Table ). Conclusion: Greater decrease in LV volume and area during cardiac arrest are associated with low CPP during CPR and poor resuscitation outcome. LV dimensions prior to start CPR might therefore affect the effectiveness of resuscitation interventions.