Alteration in calcium metabolism in cardiac hypertrophy and failure caused by bacterial infection.

ABSTRACT

Left ventricular hypertrophy was seen in catheterized, uninfected rabbits, whereas contractile failure superimposed upon hypertrophy was observed in catheterized animals after injection with Streptococcus viridans within six days. The infected animals showed marked changes in the ultrastructure of the left heart in comparison to the uninfected rabbits. The levels of calcium and potassium were decreased, whereas sodium was increased in both infected and uninfected hearts; however, magnesium levels did not change in uninfected hearts but were decreased at three days and increased at six days of infection. The microsomal calcium uptake was decreased in six-day uninfected as well as three-and six-day infected hearts. On the other hand, the mitochondrial calcium uptake was increased in six-day uninfected and three-day infected hearts but decreased in six-day infected hearts. The sarcolemmal calcium binding and (Na+,K+)ATPase activities were decreased in six-day uninfected as well as three- and six-day infected hearts. These results dramatic changes in intracellular calcium metabolism in myocardial hypertrophy and failure caused by bacterial infection.