The risk of RF-induced currents makes use of electrically conductive guidewires for cardiac catheterization procedures potentially unsafe for MRI. By using a parallel transmit coil array (PTx) system it is possible to generate RF field modes that can be utilized for safe imaging, and also guidewire visualization. As the induced RF currents can change with the guidewire position and operator handling, the control modes become a moving target. In this work we present an actively controlled PTx system that enables safe operation during a procedure in which electrical conditions are changing, and demonstrate this experimentally.