Role of myocardial T1 mapping in arrhythmogenic right ventricular cardiomyopathy

Abstract Background T1 mapping by cardiovascular magnetic resonance (CMR) is an accurate tool to assess myocardial extracellular space with wider clinical applications in the aetiological characterization of cardiomyopathies. The aims of the study were to explore a possible role of myocardial T1 mapping in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) and in first-degree relatives at risk and to investigate the possible relationship between left ventricular (LV) involvement at CMR and ECG features. Methods Thirty patients with ARVC (47% males, mean age 42±22 years) and 59 first-degree relatives who did not fulfil ARVC diagnostic Task Force criteria, underwent full diagnostic work-up including CMR with native and post-contrast T1 mapping. Results The CMR was abnormal in 26 (86%) patients with ARVC. The RV was affected in isolation in 13 (43%) patients. Prior to T1 mapping assessment, 2 (7%) patients exhibited isolated LV involvement and 11 (36%) patients showed features of biventricular disease. Left ventricular involvement was manifested as detectable LV late gadolinium enhancement (LGE) in 12 out of 13 cases. According to pre-specified septal T1 mapping thresholds, 11 (37%) patients showed abnormally high native T1 values. Myocardial T1 mapping was higher than normal in 5 (17%) patients who would have been classified as exhibiting a normal LV by conventional imaging. The proportion of patients with abnormal T1 values was similar in patients with or without LGE. Myocardial T1 mapping was higher than normal in 22 (37%) of the 59 first-degree relatives. Conclusions Native and/or post contrast myocardial T1 values are raised in almost half of patients with ARVC and in a similar proportion of unaffected first-degree relatives. T1 mapping offers the potential for early detection of LV involvement in patients with ARVC and in first-degree relatives at risk. Funding Acknowledgement Type of funding source: None