Cytotoxic shock was a medical condition that was caused by abnormally high levels of cytotoxin in a humanoid's body. Some of the symptoms leading up to this condition included a rapid and irregular pulse rate.
In 2375, B'Elanna Torres went into cytotoxic shock after her autonomic functions were overtaken by a cytoplasmic lifeform. The Doctor was able to stabilize the condition by administering two milligrams of inaprovaline. (VOY: "Nothing Human")