ALT CMR in patients with arrhythmia is challenging. Arrhythmias may result in skipped or ectopic heartbeats, causing issues with data acquisition and image reconstruction. This results in degraded image quality and therefore inferior diagnostic accuracy. Challenges in image acquisition may be overcome with dedicated techniques such as arrhythmia detection/rejection, or real-time cine imaging with or without Compressed Sensing and adaptive triggering. Assessment for fibrosis with LGE sequences can also be optimized in arrhythmia. All these approaches may result in more efficient scan times and improve image quality, which leads to more accurate cardiac assessments and better patient care. The authors discuss indications and imaging techniques. And they provide solutions for improving image quality and suggest a workflow for dealing with arrythmia during the examination process.