title: Novel methods to evaluate controlled reperfusion techniques in cardiac surgery.
abstract: BACKGROUND
  This manuscript describes two novel techniques that may be useful for comparing methods to reperfuse the heart during cardiac operations. These techniques are based on measurements of intra-myocyte ion content and the analysis of reperfusion arrhythmias.
  
  
  METHODS
  Myocyte ion content was measured in normal porcine hearts before and after ischemia (cardioplegic arrest, CP arrest) using atomic absorption spectroscopy. A cobalt-EDTA complex served as the extra-cellular marker. Cobalt-EDTA was infused into the aorta together with blood or cardioplegia (CP) solution. Myocardial biopsies were taken prior to CP arrest and upon successful defibrillation 5 min after initiating reperfusion. Ventricular fibrillation (VF) was recorded prior to ischemia, and then during reperfusion. VF wavefront (WF) morphology and propagation patterns were analyzed using computer algorithms. Electrophysiologic variables for measuring VF included the multiplicity index (a descriptor of VF organization), the number of WFs detected (nwaves/s) and the mean peak first derivative of electrogram voltage with respect to time (mp d V/dt).
  
  
  RESULTS
  Intra-cellular sodium content increased, while intra-cellular magnesium content decreased between control and reperfusion measurements (p < 0.05). Electrophysiologic recovery was characterized by increasingly rapid depolarization (i.e. more negative mp d V/dt) and an increasing nwaves/s during the first minute of post-CP reperfusion.
  
  
  CONCLUSIONS
  Atomic absorption spectroscopy and computer-based analysis of reperfusion VF successfully measured metabolic and electrophysiologic events that occurred during controlled reperfusion. These methods may be useful for comparing controlled reperfusion techniques.
authors.affiliation: Department of Surgery, School of Medicine, University of Alabama at Birmingham 35294-0007, USA.
authors.forename: J L
authors.initials: JL
authors.lastname: Skinner
authors.forename: S B
authors.initials: SB
authors.lastname: Digerness
authors.forename: R D
authors.initials: RD
authors.lastname: Spruell
authors.forename: J M
authors.initials: JM
authors.lastname: Rogers
authors.forename: C R
authors.initials: CR
authors.lastname: Katholi
authors.forename: G P
authors.initials: GP
authors.lastname: Walcott
authors.forename: R E
authors.initials: RE
authors.lastname: Ideker
authors.forename: W L
authors.initials: WL
authors.lastname: Holman
mesh_terms: D000818:Animals; D006348:Cardiac Surgical Procedures; D002309:Cardiology / Q000379:methods / Q000639:trends; D004594:Electrophysiology; D005260:Female; D006321:Heart / Q000503:physiopathology; D006324:Heart Arrest, Induced; D008274:Magnesium / Q000378:metabolism; D008297:Male; D017202:Myocardial Ischemia / Q000378:metabolism; D015425:Myocardial Reperfusion / Q000379:methods* / Q000592:standards*; D009206:Myocardium / Q000378:metabolism; D012964:Sodium / Q000378:metabolism; D013054:Spectrophotometry, Atomic; D013552:Swine; D014693:Ventricular Fibrillation / Q000503:physiopathology
chemical_list: D012964:Sodium; D008274:Magnesium