Ventricular fibrillation scaling exponent can guide timing of defibrillation and other therapies.

Background: The scaling exponent (ScE) of the ventricular fibrillation (VF) waveform correlates with duration of VF and predicts defibrillation outcome. We compared 4 therapeutic approaches to the treatment of VF of various durations.

Methods And Results: Seventy-two swine (19.

Immediate defibrillation versus interventions first in a swine model of prolonged ventricular fibrillation.

Objectives: we compared time-dependent rescue shock success when delivered immediately, to defibrillation preceded by 3 min of CPR, with and without high dose epinephrine (HDE) in a swine model of prolonged ventricular fibrillation (VF). Our hypotheses were that pretreatment with CPR and HDE would produce higher rates of successful first-shock defibrillation and would prevent decay of the VF waveform, as measured by the scaling exponent (ScE), when compared to immediate defibrillation. We also sought to determine the predictive value of the ScE in determining post-shock outcomes.

Dynamic nature of electrocardiographic waveform predicts rescue shock outcome in porcine ventricular fibrillation.

Study Objective: Survival decreases with duration of ventricular fibrillation, and it is possible that failed rescue shocks increase myocardial damage. Structure in the ECG signal during ventricular fibrillation can be quantified by using the scaling exponent, a dimensionless measure that correlates with ventricular fibrillation duration. This study examined whether the scaling exponent could predict rescue shock success and whether unsuccessful rescue shocks altered the structure of the ventricular fibrillation waveform and the responsiveness to subsequent rescue shocks.

Hypothermic reperfusion after cardiac arrest augments brain-derived neurotrophic factor activation.

Induction of mild hypothermia improves neurologic outcome after global cerebral ischemia. This study measured levels of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF) in hippocampal tissue of rats after resuscitation from 8 minutes of normothermic, asphyxial cardiac arrest. After resuscitation, rats were maintained either at normal temperature (37 degrees C) or cooled to mild hypothermia (33 degrees C, beginning 60 minutes after resuscitation).