Malnutrition and the heart: a microscopic analysis.

The effect of starvation on heart morphology was studied in the rat after total caloric deprivation. Morphometric analysis in subendocardial and subepicardial regions in the left and right ventricle was performed before and after starvation. A progressive fall in body weight was noted together with a biphasic change in ventricular weight. The ratio heart/body weight showed a continuous rise initially but stabilized at high levels in the later stage of starvation (p less than or equal to 0.005). The observed changes were analogous in the right and left ventricle. After starvation a significant increase in myocyte volume fraction was noted (p less than or equal to 0.01), but no regional differences were observed with respect to subendocardial-subepicardial and right-left ventricular zone comparison. The change in the non-myocyte fraction is situated in the vascular space and connective tissue. The volume fraction of non-capillary interstitial connective tissue, however, is significantly greater in the right ventricle than in the left (p less than or equal to 0.005). We conclude that in total starvation, after an initial rapid decline in heart weight, the heart is relatively spared. This leads to a rising heart/body weight ratio, until the later stage of malnutrition when the heart undergoes a hypotrophy to the same extent as other organs. This hypotrophy gives rise to a relative increase in myocyte volume fraction and a parallel decrease in capillary volume without major changes in the interstitial non-capillary connective tissue compartment.