Cardioplegia-induced cell swelling: prevention by normothermic infusion.
BACKGROUND
Previous work has shown significant swelling of isolated rabbit myocytes exposed to cold hyperkalemic cardioplegia; however, the effect of warm hyperkalemic cardioplegia on myocyte volume is unknown. This study examined the effect of warm hyperkalemic cardioplegia (St. Thomas' solution) on myocyte volume.


METHODS
Myocytes were enzymatically isolated and placed on an inverted video microscope. Tyrode's solution (37 degrees C) was infused for 10 minutes to establish baseline cell volumes. Subsequently, either the control Tyrode's or St. Thomas' was infused either at 37 degrees C and 9 degrees C respectively (n = 5 for all groups) for 20 minutes, followed by a 30-minute reperfusion with 37 degrees C Tyrode's. Cell volume was determined from cell images captured every 5 minutes.


RESULTS
Myocyte swelling occurred rapidly on exposure to cold St. Thomas' solution to a maximum of 9.8 +/- 2.1% (p < 0.001). In contrast, myocytes exposed to warm cardioplegia did not show any volume changes during exposure to cardioplegia. However, upon reexposure to Tyrode's, these cells showed shrinkage below their baseline volume (p < 0.001).


CONCLUSIONS
The cell swelling associated with hypothermic cardioplegia is prevented by normothermic infusion.
Stephenson
E R
ER
Section of Cardiothoracic and Vascular Surgery, The Milton S. Hershey Medical Center, Penn State Geisinger Health System, Hershey, Pennsylvania, USA.
Jayawant
A M
AM
Baumgarten
C M
CM
Damiano
R J
RJ
D000818:Animals; D001639:Bicarbonates / Q000494:pharmacology; D002122:Calcium Chloride / Q000494:pharmacology; D002314:Cardioplegic Solutions / Q000494:pharmacology*; D048429:Cell Size; D003080:Cold Temperature; D006324:Heart Arrest, Induced; D066298:In Vitro Techniques; D008274:Magnesium / Q000494:pharmacology; D009206:Myocardium / Q000166:cytology*; D011189:Potassium Chloride / Q000494:pharmacology; D011817:Rabbits; D012965:Sodium Chloride / Q000494:pharmacology
D001639:Bicarbonates; D002314:Cardioplegic Solutions; C041711:St. Thomas' Hospital cardioplegic solution; D012965:Sodium Chloride; D011189:Potassium Chloride; D008274:Magnesium; D002122:Calcium Chloride