The purpose of this study is to assess the risk of serious cardiac events associated with the use of domperidone in a cohort of patients with Parkinson's disease. More specifically, the study objective is to assess the risk of ventricular tachyarrhythmia and sudden cardiac death associated with the use of domperidone compared to no use in patients with Parkinson's disease. In addition, the investigators would also like to determine whether the risk of ventricular arrhythmia and sudden cardiac death increases with the dose of domperidone in patients with Parkinson's disease.