Abstract P150: Comparison Between Invasive and Noninvasive Assessment of Myocardial Function in A Rat Model of Cardiac Arrest and CPR
Background Placement of a pressure catheter into the left ventricle for monitoring myocardial function is a standard technique in animal models of cardiac arrest and CPR. However, this technique is invasive and time-limited. We therefore sought to compare this approach with the noninvasive echocardiographic assessment for monitoring myocardial function in rat model of cardiac arrest and CPR. We hypothesized that echocardiographically assessed myocardial function could be correlated to the invasive left ventricular function measurements.
Methods Ventricular fibrillation (VF) was induced in 8 male Sprague-Dawley rats weighing 543±27g. After 8 minutes of untreated VF, CPR was performed for 6 minutes prior to defibrillation. A PE-50 catheter was advanced into left ventricle for measuring the left ventricular pressure (LVP). dP/dt40 was calculated based on LVP. Left ventricular ejection fraction (EF) was obtained with the aid of a Philips echocardiographic system utilizing a 15.0–7 MHz broadband compact linear ultrasound transducer. Both the invasive and noninvasive measurements were obtained at baseline, 1, 2, 3, and 4 hours after return of spontaneous circulation.
Results All animals were successfully resuscitated. Both dP/dt40 and EF were significantly decreased after resuscitation (P<0.05). The noninvasive assessed EF was highly correlated to dP/dt40 (R=0.75, P<0.01).
Conclusion The echocardiographically assessed myocardial function is significantly correlated with the standard invasive monitoring measurements in a rat model of cardiac arrest and CPR.