Direct effects of purified staphylococcal toxic shock syndrome toxin 1 on myocardial function of isolated rabbit atria.

Toxic shock syndrome is associated with reversible cardiomyopathy. The cardiac dysfunction may be mediated by toxic shock syndrome toxin 1 (TSST-1), an exotoxin generated by Staphylococcus aureus. However, the effects of purified TSST-1 on cardiac function are unknown. In a study of the toxin's effect on myocardial function, TSST-1 (200 ng/mL) was added to muscle baths containing isolated rabbit atria. TSST-1 caused time-dependent inhibition of developed force (systolic function) but did not alter resting force (an index of muscle stiffness or cardiac compliance). These data show that TSST-1 can directly inhibit myocardial function, but the significance of this effect in patients with toxic shock syndrome remains to be determined.