Regional variation in myocardial water content in the edematous pig heart.
BACKGROUND
The purpose of this study was to examine regional variation in myocardial water content (%MWC) throughout the iatrogenically edematous pig heart.


METHODS
Edema was induced by hemodilution in domestic swine (n = 26). Hearts were arrested with potassium chloride. The left ventricular free wall (LVFW), interventricular septum (IVS), and right ventricular free wall (RVFW) were biopsied at the apex, base, and equator. Full-thickness biopsy (Full, 0.5-1 g) and subendocardial (Endo, 0.1-0.2 g) biopsies were removed from each region. %MWC was determined for each biopsy.


RESULTS
The %MWC for all hearts were as follows: Endo, 81.1 +/- 0.1, and Full, 80.6 +/- 0.1* (*P < 0.02); apex, 81.1 +/- 0.2*, equator, 80.7 +/- 0.2, and base, 80.4 +/- 0.2 (*P < 0.02); RVFW, 81.4 +/- 0.3*, IVS, 80.8 +/- 0.2*, and LVFW, 80.3 +/- 0.1* (*P < 0.02). For 18 hearts with LV samples with average %MWC >or= 80%, the percentages were apex, 81.4 +/- 0.2*, equator, 81.0 +/- 0.2*, and base, 80.6 +/- 0.2* (*P < 0.02) (repeated measures, ANOVA).


CONCLUSIONS
In the iatrogenically edematous porcine heart, a significant water gradient exists, with Endo > Full, apex > equator > base, and RVFW > IVS > LVFW. These results indicate that when examining edema, consistent biopsy results depend on a reproducible sampling site. Water content tends to be highest in thin-walled portions of the heart, suggesting that contractile force may be important in the distribution of edema.
Division of Cardiothoracic Surgery, Department of Surgery, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA.
Chao Xiang
CX
Jia
David G
DG
Rabkin
Joseph P
JP
Hart
David A
DA
Dean
Santos A
SA
Cabreriza
Alan D
AD
Weinberg
Henry M
HM
Spotnitz
D000818:Animals; D001706:Biopsy; D002315:Cardiopulmonary Bypass; D004489:Edema, Cardiac / Q000378:metabolism* / Q000473:pathology* / Q000601:surgery; D006346:Heart Septum / Q000378:metabolism / Q000473:pathology; D006438:Hemodilution / Q000009:adverse effects; D007049:Iatrogenic Disease; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology*; D013552:Swine; D016276:Ventricular Function; D014867:Water / Q000378:metabolism*
D014867:Water