3.Romidepsin is a histone deacetylase (HDAC) inhibitor that has shown responses in relapsed or refractory cutaneous T-cell lymphoma (CTCL) and peripheral T-cell lymphoma (PTCL) in phase 2 trials. Patients receiving romidepsin should be monitored for electrocardiographic (EKG) changes. Which one of the following treatment-emergent morphological changes in EKGs has been observed several times in the clinical studies?

A. QT-prolongation

B. T-wave and ST-segment changes

C. Second-degree heart block

D. Frequent premature atrial contractions (PACs)