Abstract 9446: Periodic Acceleration (pGz) Preserves Heart Rate Variability After Cardiac Arrest
Heart Rate Variability (HRV) and lack thereof is important in predicting neurological outcome after brain injury and cardiac arrest (CA). The post CA period has decreased HRV compared to pre-arrest, and interventions such hypothermia may preserve HRV. Periodic acceleration (pGz) the sinusoidal head to foot motion of the supine body with a motion platform increases endothelial derived NO (eNO) and neuronal nitric oxide (nNOS) in heart via pulsatile shear stress, and preconditions from global and focal ischemia reperfusion injury (I/R). NO has a facilitator role on vagal chronotropism and inhibition of nNOS reduces HRV. CA is a model of whole body I/R. This study tests whether pGz applied prior to whole body I/R preserves HRV in a pig model of CA. Fourteen male swine (40-50lbs) were anesthetized, intubated and instrumented to measure EKG and hemodynamics. They were placed on a motion platform and randomized to 1 hr of pGz (180 cpm and Gz ± 0.4) or none control (C). VF was electrically induced and unsupported for 8 min, followed by chest compression and defibrillation until return of spontaneous circulation (ROSC) or 10 min. Short term HRV (excluding ectopic beats) was measured including; time domain; SDNN (standard deviation of normal to normal intervals), RMSSD (square root of the mean squared differences of successive normal to normal intervals) and frequency domain, at baseline (BL1), after pGz or C (BL2) and 30, to 180 mins after ROSC (ROSC30, 60,120,180 ). All animals had ROSC after a median of 4 defibrillation attempts. There were no differences between groups in defibrillation attempts, time to ROSC, arterial blood gases or hemodynamics over time. pGz animals had less hemodynamically significant arrhythmias in the first 30 mins ROSC; C (35) vs pGz (7) (p< 0.05) Data mean ±SEM * p < 0.05 C vs pGz. pGz applied prior to I/R in addition to being cardioprotective preserves HRV and is a novel non invasive method to preserve autonomic nervous system output and precondition the myocardium.
- © 2013 by American Heart Association, Inc.