Frequent premature ventricular beats (PVBs) are common, negatively affects the quality of life for many patients, and can lead to impaired contractile function. Rule-out of structural heart disease is key in the assessment of PVBs. Cardiac MR has a high sensitivity for structural heart disease, but the diagnostic gain from this resource-demanding procedure in the work-up of patients with PVBs is unknown. There is a need to establish the role of MR in the evaluation of patients with PVBs to improve diagnostic efficacy, establish treatment strategies, and promote further research. This project will answer three key questions: 1) What is the diagnostic gain from cardiac MR in patients with PVBs? 2) Is MR the real gold standard to rule-out structural heart disease in patients with PVBs? 3) Can non-invasive heart rate parameters guide the strategy for induction of PVBs during invasive electrophysiological procedures?