Abstract 2708: Recovery of Cardiac Output after Defibrillation
Background: Conversion into sinus or paceable rhythm after ventricular fibrillation (VF) does not guarantee proper organ perfusion. Inadequate cardiac output (CO) after cardiac arrest is a major determinant of increased morbidity and mortality (1). Diminished left ventricular ejection fraction (LVEF) may predispose to persistent low cardiac output following successful defibrillation. We thus studied the impact of LVEF on the recovery of CO after defibrillation.
Methods: After IRB approval and with informed consent we investigated 80 patients undergoing implantable cardioverter/defibrillator insertion with threshold testing in local anesthesia. Patients were breathing spontaneously and received 0.1 mg/kg etomidate, an anesthetic without cardiorespiratory depression, before induction of VF. According to preoperative LVEF, systolic function was either classified as normal (> 50%), moderately (30–50%) or severely reduced (< 30%). Beat-to-beat CO was measured (LiDCO TM plus, LiDCO Ltd, UK) and baseline CO (i.e. before induction of VF), averaged over 5 beats, was compared with CO determined immediately after defibrillation. Only the first defibrillation was used for statistical analysis.
Results: Mean duration of cardiac arrest and heart rate after defibrillation were not different between groups. There were no incidents that required resuscitative measures. Neither vasopressors nor inotropes were administered. CO data are given as median (Min/Max) or absolute values.
Discussion: These results indicate that it is predominantly LVEF that determines recovery of CO after VF. Patients without normal LVEF lack the ability to quickly restore CO and seldom show an increase in systolic ventricular function after VF. Thus, organ perfusion may still be compromised despite successful defibrillation in patients with low LVEF. This could explain greater neuronal injury after VF (2).