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Cardioplegia-induced cell swelling: prevention by normothermic infusion
E R Stephenson1, A M Jayawant, C M Baumgarten
1Section of Cardiothoracic and Vascular Surgery, The Milton S. Hershey Medical Center, Penn State Geisinger Health System, Hershey, Pennsylvania, USA.
The Annals of Thoracic Surgery
|July 6, 2000
Summary
Warm hyperkalemic cardioplegia prevents cold-induced myocyte swelling. Normothermic infusion avoids cell volume changes, unlike hypothermic cardioplegia which causes swelling and subsequent shrinkage.
Area of Science:
- Cardiology
- Cell Biology
- Biochemistry
Background:
- Previous studies indicate cold hyperkalemic cardioplegia causes significant rabbit myocyte swelling.
- The impact of warm hyperkalemic cardioplegia on myocyte volume remains uninvestigated.
- This study addresses the effect of warm cardioplegia on myocyte volume.
Purpose of the Study:
- To investigate the effect of warm hyperkalemic cardioplegia on isolated rabbit myocyte volume.
- To compare the effects of normothermic versus hypothermic cardioplegia on myocyte volume.
Main Methods:
- Rabbit myocytes were enzymatically isolated and imaged using an inverted video microscope.
- Cells were exposed to either control Tyrode's solution or St. Thomas' solution at varying temperatures (37°C or 9°C).
- Cell volumes were measured during cardioplegia infusion and subsequent reperfusion.
Main Results:
- Exposure to cold St. Thomas' solution induced rapid myocyte swelling (9.8 ± 2.1%, p < 0.001).
- Myocytes exposed to warm St. Thomas' solution showed no volume changes during infusion.
- Normothermic cardioplegia-treated myocytes exhibited shrinkage below baseline upon reperfusion (p < 0.001).
Conclusions:
- Normothermic infusion of cardioplegia effectively prevents the cell swelling associated with hypothermic cardioplegia.
- Warm hyperkalemic cardioplegia does not cause myocyte swelling but can lead to subsequent cell shrinkage.