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Preischemic perfusion of hypertrophied myocardium with perfluorocarbons
M S Soberman1, J D Sink, G C Forest
1Joseph B. Whitehead Department of Surgery, Emory University School of Medicine, Atlanta, Georgia 30322.
Insights
Preischemic perfusion with oxygenated perfluorocarbon cardioplegia (FC-43) can restore normal ATP levels in hypertrophied rat hearts. This intervention significantly prolongs the time before ischemic contracture, enhancing cardiac tolerance to ischemia.
Area of Science:
- Cardiology
- Biochemistry
- Physiology
Background:
- Hypertrophied myocardium exhibits increased susceptibility to ischemic injury.
- These hearts have lower pre-ischemic high-energy phosphate stores and shorter tolerance to ischemia.
- Ischemic contracture develops more rapidly in hypertrophied hearts compared to normal hearts.
Purpose of the Study:
- To evaluate the efficacy of preischemic arrested perfusion with oxygenated, glucose-containing perfluorocarbon cardioplegia (FC-43).
- To determine if FC-43 perfusion can restore normal myocardial ATP stores in hypertrophied rat hearts.
- To assess the impact of FC-43 perfusion on prolonging the duration of global ischemia before contracture initiation.
Main Methods:
- Utilized a modified Langendorff preparation for normal (NL) and hypertrophied (spontaneously hypertensive rats - SHR) rat hearts.
- Subjected hearts to 2 or 15 minutes of preischemic, arrested perfusion with FC-43.
- Measured adenosine triphosphate (ATP) levels via High-Performance Liquid Chromatography (HPLC) and recorded the time to ischemic contracture initiation.
Main Results:
- Two minutes of FC-43 perfusion restored ATP levels in SHR hearts to those of normal controls (P = NS).
- FC-43 perfusion significantly prolonged the time to initiation of ischemic contracture by 107% in the SHR group.
- No significant difference in ATP levels was observed between normal controls and SHR hearts post-perfusion.
Conclusions:
- Oxygenated perfluorocarbon cardioplegia (FC-43) effectively restores myocardial ATP stores in hypertrophied hearts.
- FC-43 perfusion enhances tolerance to global ischemia by delaying ischemic contracture.
- Perfluorocarbons represent a promising vehicle for interventions aimed at improving hypertrophied heart resistance to ischemia.
Abstract:
The increased susceptibility of hypertrophied myocardium to ischemic injury is well known. Hypertrophied hearts possess lower preischemic high energy phosphate stores and develop ischemic contracture following a shorter ischemic interval than normal hearts. The purpose of this study was to determine the ability of preischemic, arrested perfusion of the hypertrophied rat heart with oxygenated, glucose-containing perfluorocarbon cardioplegia (FC-43) to restore myocardial ATP stores to normal and prolong the duration of global ischemia prior to contracture initiation. Hearts from normal (NL) rats and hypertrophied hearts from spontaneously hypertensive rats (SHR) were subjected to 2 or 15 min of preischemic, arrested perfusion with FC-43 utilizing a modified Langendorff preparation. ATP was determined via HPLC and time to initiation of ischemic contracture was measured. Two minutes of FC-43 perfusion restored ATP in the SHR group to normal levels (P = NS compared to normal controls) and prolonged the time to initiation of ischemic contracture by 107%. Perfluorocarbons, with their unique oxygen-carrying properties, may be an ideal vehicle for intervention designed to enhance the tolerance of hypertrophied hearts to ischemia.