: To study whether female patients with active rheumatoid arthritis (RA) have myocardial abnormalities and whether progression of myocardial involvement can be attenuated by disease-modifying anti-rheumatic drugs (DMARDs). : Cardiac magnetic resonance (cMR; 1.5 or 3.0 T), including late gadolinium enhancement (LGE), T1 relaxation time, and ventricular functions, was performed in 30 patients with untreated active early RA starting first DMARDs, and 28 patients with chronic RA with inadequate response to conventional synthetic DMARDs starting biological DMARDs. cMR was repeated in RA patients 1 year later. cMR was conducted once in 22 fibromyalgia (FM) subjects and in 35 healthy volunteers serving as controls. All subjects were non-smoking females without coronary heart disease, heart failure, or diabetes. : Compared with controls, 58 RA patients had slightly lower ventricular function, although in the normal range, and longer T1 time at baseline. None of the FM subjects had LGE, but it was frequent in RA (67%). During the 1 year DMARD treatment, Disease Activity Score based on 28-joint count-C-reactive protein declined, ventricular functions tended to improve, but the number of patients with LGE remained unchanged. However, the number of LGE-positive heart segments either decreased or stayed the same in 91% of RA patients. In early RA patients, achieving tight remission was associated with LGE stabilization, after adjustment for age, metabolic syndrome, baseline inflammatory activity, and leisure-time physical activity. : Treatment targeted to tight remission in early stages of RA seems to be important to prevent not only joint damage but also myocardial abnormalities.