Abstract 18293: Temporal Comparison of Mitochondrial Dysfunction in a Porcine Model of Untreated Ventricular Fibrillation
Introduction: The ability of a heart in ventricular fibrillation (VF) to achieve return of spontaneous circulation depends on the bioenergetic state of the cardiomyocytes and the capability of the mitochondria to respire and produce ATP. Our goal was to investigate the temporal effect on cardiac mitochondrial respiration, calcium retention capacity and ATP synthesis during prolonged untreated VF.
Hypothesis: We hypothesized that the ability of cardiac mitochondria to respire, tolerate calcium stress and produce ATP is preserved during prolonged untreated VF of up to 30 minutes.
Methods: Anaesthetized and intubated female pigs (n=7) were used to compare the mitochondrial function of isolated mitochondria and the bioenergetics of cardiac left ventricular (LV) tissue over time. VF was induced using a temporary pacing wire. Serial heart biopsies were taken at minutes 5, 10, 15 and 30, and were randomized to be taken consecutively from either base or apex. Cardiac mitochondria were isolated via differential centrifugation. Isolated mitochondrial respiration, calcium retention capacity and ATP synthesis were assessed using complex 1 (Pyruvate + Malate) and complex 2 (Rotenone + Succinate). For controls, data from seven naïve (non-ischemic non-fibrillating) hearts were utilized from a different group of animals. Results were analyzed by one way ANOVA and p<0.05 was reported as significant.
Results: The effect of time on a fibrillating heart of up to 15 minutes does not impair the cardiac mitochondria to respire effectively and produce ATP (Table 1). Mitochondrial function until minute 15 of untreated VF is effectively similar to naive hearts. Mitochondrial functional state decreases after 30 minutes of untreated VF.
Conclusion: Our results indicate that cardiac mitochondrial function and ability to respire and produce ATP remains intact for up to 15 minutes of untreated VF. Mitochondrial function appears compromised after 30 minutes of global ischemia and no flow.
- Ventricular fibrillation
- Mitochondrial energetics, heart failure, arrhythmias
- Ischemic Injury
Author Disclosures: K. Chandra Shekar: None. T.R. Matsuura: None. J.A. Bartos: None. S.H. McKnite: None. J.N. Rees: None. D. Yannopoulos: None.
- © 2016 by American Heart Association, Inc.