European Journal of Cardio-Thoracic Surgery, Vol 5, 395-399, Copyright © 1991 by European Association for Cardio-thoracic Surgery
Effect of high-volume cardioplegia on small-amplitude electrical activity during cardioplegia arrest
RW Landymore, AE Marble, P Eng, MA MacAulay, A Trillo and QY Li
Department of Surgery, Dalhousie University, Halifax, Nova Scotia, Canada.
The effects of high-volume cardioplegia on the presence of small- amplitude
electrical activity during cardioplegia arrest were investigated in 19
mongrel dogs. The animals were randomly assigned to receive either
high-volume crystalloid cardioplegia (HV-plege) or crystalloid cardioplegia
guided by continuous electrical monitoring (V- plege). Cardiac index, left
ventricular stroke work index dp/dt, and myocardial oxygen consumption were
measured before bypass and following 90 min ischemia and 45 min
reperfusion. Biopsies were taken for measurement of adenosine triphosphate
(ATP) and examination of myocardial ultrastructure. Nine animals received
HV-plege, while the remaining 10 animals received cardioplegia guided by
voltage criteria. Small-amplitude electrical potentials were recorded
within 10-15 min after the infusion of cardioplegia in all animals
receiving cardioplegia guided by voltage criteria. Electrical activity,
however, was immediately abolished by reinfusion of cardioplegia. HV-plege
reduced the incidence of small-amplitude electrical activity during
cardioplegia arrest but did not prevent electrical activity. Left
ventricular function and myocardial ultrastructure were better preserved
when cardioplegia was guided by electrical monitoring. ATP decreased
similarly in both groups following cardioplegic arrest, but myocardial
oxygen consumption was significantly higher following the arrest in the
V-plege group. Conclusions: HV-plege does not prevent small-amplitude
electrical activity and may have adverse effects on myocardial metabolic
and functional recovery.