Association of intramyocardial high energy phosphate concentrations with quantitative measures of the ventricular fibrillation electrocardiogram waveform.
BACKGROUND
Quantitative measures of the ventricular fibrillation (VF) electrocardiogram (ECG) have been correlated with the success of rescue shocks, making them ideal measures for guiding resuscitative interventions. Correlation of intramyocardial energy stores with the change in quantitative VF ECG measures would provide mechanistic insight into their utility. We sought to investigate the relationship between intramyocardial energy stores and four quantitative ECG measures.


METHODS
Eighteen mixed-breed, domestic swine were sedated, anaesthetized and paralyzed. Swine were block randomized into three groups receiving 5, 10, or 15 min of untreated VF. Thoracotomy was performed and the heart was delivered. VF was induced by a 100 mA transthoracic shock while ECG was recorded. Biopsies of myocardial tissue were taken from the left and right ventricles after the prescribed duration of VF. Adenosine triphosphate (ATP) and adenosine diphosphate (ADP) concentrations in the tissue samples were measured. ECG data immediately prior to each biopsy were analyzed by each of four quantitative ECG methods: Scaling Exponent (ScE), Median Slope (MS), Amplitude Spectrum Area (AMSA), and logarithm of the Absolute Correlation (LAC). ATP and ADP concentrations of VF duration groups were compared. ATP and ADP concentrations were regressed against each quantitative ECG measure.


RESULTS
ATP concentrations differed between VF duration groups, but ADP concentrations differed only between 5 and 10 min groups. A significant association existed between ATP and three quantitative measures--ScE, MS, and AMSA--but no significant relationship was found for ADP.


CONCLUSIONS
Intramyocardial ATP levels correlate with quantitative measures of the ECG during ventricular fibrillation.
Salcido
David D
DD
Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA 15216, USA. salcidodd@upmc.edu
Menegazzi
James J
JJ
Suffoletto
Brian P
BP
Logue
Eric S
ES
Sherman
Lawrence D
LD
D000244:Adenosine Diphosphate / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001706:Biopsy; D004195:Disease Models, Animal; D004562:Electrocardiography; D004734:Energy Metabolism; D009206:Myocardium / Q000378:metabolism*; D012720:Severity of Illness Index; D013552:Swine; D014693:Ventricular Fibrillation / Q000378:metabolism / Q000503:physiopathology*
D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate