Abstract 590: Evaluation of the Effects of Cardiac Arrest and CPR Using Intracardiac Echocardiography

Abstract

For every minute of cardiac arrest, mortality increases by 10%. Still, the variablity of meaningful neurologic survival suggests multiple factors involved in the hypoxia and encephalopathy of cardiac arrest (CA). We studied the cardiac chamber environment during ventricular fibrillation and asystole using direct ultrasound visualization using real-time intracardiac echocardiography (ICE). Four pigs were studied under general anesthesia per protocol. Venous access was obtained for catheter placement within the right heart. A bipolar paciing wire was placed into the right ventricle. A 10 French Acuson ICE catheter was placed into the right atrium using fluoroscopy. Baseline images were obtained. Ventricular fibrillation was induced using direct current energy. 30 minutes of ventricular fibrillation and terminal asystole was observed. Chest compressions were delivered intermittently with direct visualization of effects. Intra-chamber thrombus was quantified by chamber and by arrhythmia. All subjects began to form intracardiac thrombus within 1 minute of ventricular fibrillation. The persistence of sinus rhythm during fibrillation prevented thrombus formation in the atria and the basal portions of both ventricles. The thrombus was predominantly in the right heart within the first 4 minutes of CA. ICE documents that chest compressions completely clear the thrombus when delivered within the first five minutes of CA. Asystole led to more solidified thrombus that was more difficult to clear. Thrombus formation during CA is marked and may be a predominant reason for neurologic damage post resuscitation. Asystole was associated with complete chamber thrombus in comparison to ventricular fibrillation.