The ever-increasing number of chemical compounds synthesized by chemical
and pharmaceutical industries has prompted the development of innovative in
vitro research methods for optimizing potential drug candidates. Many of these
new approaches show promise for effective and inexpensive toxicity assessment.
In addition to providing potential toxicity assessments, in vitro methods serve as
ideal models to investigate and understand mechanisms of action. In the previous
edition (1), we discussed in vitro cytotoxicity modeling and the credence of in
vitro models. Three important criteria need to be considered in the selection of
an in vitro method are (i) the assay must correlate well with the in vivo biological
response being modeled; (ii) the assay must have a biological basis that links it to
the cell injury or pharmacological process; and (iii) the assay should be tech-
nically reliable and reasonably easy to conduct if used for screening purposes. In
this chapter, we present a summary of the use of cardiac myocytes and two
newer approaches being used to assess cardiotoxicity. Specifically, the two new
models presented are the working heart model to evaluate cardiovascular toxicity
and hERG channel assessment to evaluate QT interval prolongation.