Idioventricular rhythm: hypervagotonia associated with placebo.

We report a case of hypervagotonia manifested by idioventricular rhythm in a healthy, athletic man who participated in a Phase I study of an investigational calcium-channel blocker. Upon breaking the study's double-blind study code, it was discovered that the subject had received placebo. We discuss this unusual finding and the implications of including athletic subjects in safety/tolerance studies.