Electrocardiographic (ECG) monitoring is recommended for some of the new and re-purposed drugs used in the treatment of multidrug-resistant tuberculosis (MDR-TB), as these drugs have been shown to prolong the QTc interval. ECG monitoring is relatively new in the management of TB patients, and has several implications for programs and providers. This review discusses what is known about QTc prolongation and the medications currently being studied or used to treat MDR-TB, and discusses strategies for managing QTc prolongation in the context of treating such a serious infectious disease. It also reviews some major implications of ECG monitoring in the field, including interpretation of ECGs and QTc intervals, management of patients with prolonged QTc intervals, and contextualizing the risk of QTc prolongation for patients being treated for MDR-TB.