Mechanical properties of rat cardiac muscle during experimental thiamine deficiency.

The intrinsic contractile properties of isolated left ventricular trabecular periods of 24, 40, and 53 days were compared with those from 35 weight-matched food-deprived animals and 25 ad libitum fed controls. Contraction mechanics were measured for each muscle when stretched to the peak of its length tension curve at 28 degrees C in oxygenated Krebs-Henseleit solution. Although both thiamine-deficient and food-deprived groups had a marked diminution in body and left ventricular weight in comparison to ad libitum fed controls, no differences in left ventricular weights from thiamine-deficient and food-deprived rats were observed. In comparison to ad libitum fed control animals, food-deprived rats exhibited a prolongation in the duration of muscle contraction and an augmentation of tension development after 40 days. Upon appearance of neurological signs at an average of 53 days of a thiamine-deficient rats exhibited a decrease in performance associated with a decrease in the duration of contraction and rate of tension development.