The existence of a diabetic cardiomyopathy has been postulated to explain the increased risk of heart failure (HF) in patients with diabetes mellitus; however, whether mechanisms specific to type 1 diabetes mellitus (T1DM) affect the myocardium is unclear. We have recently shown that poor glycemic control in patients with T1DM followed in the DCCT (Diabetes Control and Complications Trial), but not in patients with type 2 diabetes mellitus, is associated with positivity for multiple (≥2) cardiac autoantibodies, similar to a HF cohort with Chagas cardiomyopathy,1 raising the possibility of autoimmune-associated myocardial dysfunction in T1DM.
..We believe that these findings are unlikely to be the result of unrecognized myocardial infarction,5 given the rigorous ascertainment of myocardial infarction during DCCT/EDIC2,3 and lack of association between cardiac autoantibodies and myocardial scar. However, it is possible that preexisting damage to the myocardium may induce cardiac autoantibodies; in addition, eccentric remodeling is seen in athletic/trained hearts. Regardless, studies in animal models4 and patients with myocarditis suggest that the presence of ≥2 autoantibodies is a marker of a disease process that is primarily T cell mediated.1,5 Indeed, if cardiac autoantibodies were pathogenic, subjects with 1 autoantibody should have had intermediate levels of CMR abnormalities, but this was not observed.
..In conclusion, in this large cohort without prior cardiovascular disease events, cardiac autoimmunity was associated with subclinical myocardial dysfunction independently of traditional cardiovascular disease risk factors, suggesting a novel process linked to long-term glycemic exposure in T1DM. Determining whether these subjects are at higher risk of future HF will require longer follow-up.