Integrated MRI-guided radiotherapy (MRIgRT) systems perform simultaneous MRI acquisitions during radiation therapy to optimize the accuracy of dose delivery. Cardiac radiosurgery using stereotactic body radiation therapy (SBRT) is a promising new treatment option for cardiac arrhythmias. We imaged the heart with a novel ungated radial TrueFISP sequence on a 0.35 T MRIgRT system. The sequence is being developed for next generation SBRT. Image artifacts associated with the sequence were measured using a Medtronic implantable cardiac defibrillator (ICD) in hydrogel and extended 13 cm from its center. Thus, artifacts should not preclude MRIgRT for most patients with ICDs.