The objective of the study is to assess the Tpe and QTc measures in 24 hr Holter echocardiograms in patients treated with atypical antipsychotic drgs (APDs). The primary comparisons of interest are olanzapine (no QTc prolongation) to ziprasidone (QTc prolongation) and thioridazine (QTc prolongation) as well as ziprasidone (possibly low TdP risk) to thioridazine (TdP risk). Secondary comparisons will be among all APDs available. In a previously approved study, conventional 24 hr Holter electrocardiograms were recorded from a total of 78 subjects during the course of treatment with psychotropic medications and without medication (in the case of normals and unmedicated patients). These recordings will be analyzed to yield Tpe, QTc and heart rate, and other measures. Data from additional patients is needed, therefore this study will include only patients currently treated with Mellaril (thioridazine), Risperdal (risperidone) and Seroquel (quetiapine).
