BACKGROUND-AIM: Cardiac involvement at diagnosis of connective tissue disease (CTD) has been described by echocardiography. We hypothesized that cardio-vascular magnetic resonance (CMR) detects occult lesions at CTD diagnosis.PATIENTS-METHODS: CMR was performed early after diagnosis in 78 treatment-naïve CTDs (aged 43±11, 59F/19M) without cardiac involvement [5 Takayasu arteritis (TA), 4 Churg Strauss syndrome (CSS), 5 Wegener granulomatosis (WG), 16 systemic lupus erythematosus (SLE), 12 rheumatoid arthritis (RA), 8 mixed connective tissue diseases (MCTD), 12 ankylosing spondylitis (AS), 3 polymyalgia rheumatica (PMR), 8 systemic sclerosis (SSc) and 5 dermatomyositis (DM)]. Acute and chronic lesions were assessed by T2>2 with positive LGE and T2<2 with positive LGE, respectively.RESULTS: In 3/5 TA, 3/4 CSS, 4/5 WG, 10/16 SLE, 9/12 RA, 6/8 MCTD, 4/12 AS, 1/3 PMR, 2/8 SSc and 2/5 DM, the T2 ratio was higher compared to normal (2.78±0.25 vs 1.5±0.2, p<0.01). Myocarditis was identified in 1 TA, 1 SLE, 1 RA, 1 SSc and 2 DM patients; diffuse, subendocardial fibrosis in 1 CSS and 1 RA patient, while subendocardial myocardial infarction in 3 SLE, 1 MCTD, 1 PMR and 2 RA patients. CMR re-evaluation after 6 and 12months of rheumatic and cardiac treatment, available in 28/52 CTDs with increased T2 ratio, showed significant improvement in T2 ratio (p<0.001), non-significant change in LGE extent and normalisation of those with impaired LV function.CONCLUSIONS: Occult CMR lesions, including oedema, myocarditis, diffuse subendocardial fibrosis and myocardial infarction are not unusual in treatment naïve CTDs and may be reversed with appropriate treatment.