Effects of defibrillator implantation testing on myocardial metabolism.
BACKGROUND
The effects of fibrillation/defibrillation episodes (FDEs) during defibrillator implantation on myocardial metabolism were investigated at various defibrillation energies in patients with different cardiac pathologies.


METHODS
Myocardial lactate extraction (MLE) was examined during defibrillation threshold (DFT) testing in patients with either coronary artery disease (CAD, n = 20) or non-ischemic cardiomyopathy (CM, n = 10). Defibrillation pulses were released 15 seconds after induced fibrillation. A test cycle of four FDEs separated by 2-minute intervals was applied in each case.


RESULTS
Mean MLE decreased significantly from 28 +/- 4% before FDEs to 8 +/- 5% immediately after all episodes in CAD patients, but recovered to 27 +/- 7% within 2 minutes even in patients with reduced left-ventricular function. In patients with CM mean MLE decreased markedly from 29 +/- 3% to -11 +/- 3% immediately after each FDE but increased to baseline (33 +/- 8%) within the recovery period. MLE changes were independent of defibrillation energy in all cases.


CONCLUSIONS
Myocardial lactate production, suggesting cardiac ischemia, was observed in patients with CM, but not in patients with CAD. But recovery of myocardial lactate extraction was not faster in CAD patients, indicating that the fixed FDE cycle used was well tolerated by all patients.
Wolfhard
U
U
Department of Thoracic and Cardiovascular Surgery, University of Essen Medical School, Germany. ulrich.wolfhard@uni-essen.de
Knocks
M
M
Splittgerber
F H
FH
Sack
S
S
Piotrowski
J A
JA
Günnicker
M
M
D000328:Adult; D000368:Aged; D002304:Cardiac Pacing, Artificial; D009202:Cardiomyopathies / Q000378:metabolism* / Q000628:therapy; D003327:Coronary Disease / Q000378:metabolism* / Q000628:therapy; D017147:Defibrillators, Implantable; D005260:Female; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000378:metabolism*; D018487:Ventricular Dysfunction, Left / Q000378:metabolism / Q000628:therapy; D014693:Ventricular Fibrillation / Q000378:metabolism* / Q000628:therapy
D019344:Lactic Acid