Prognostic Value of Native T1 Mapping in Nonischemic Dilated Cardiomyopathy: A Prospective Observational Study from India
Background Native T1 mapping can detect diffuse myocardial fibrosis in nonischemic dilated cardiomyopathy (NIDCM), which may not be visible on late gadolinium enhancement (LGE) imaging. We assessed the prognostic relevance of native T1 mapping and its incremental value over LGE in risk stratification of NIDCM patients. Materials and Methods This prospective observational study enrolled 61 NIDCM patients who underwent cardiac magnetic resonance imaging. Patients were followed up for major adverse cardiac events (MACE), including heart failure hospitalization, sudden cardiac death, and all-cause mortality. Native septal and global T1 values were quantified. Receiver operating characteristic (ROC) curve analysis identified optimal T1 cut-off values for predicting MACE. Results During a median follow-up of 14 months, 23 patients (37.7%) experienced MACE. Mean native septal T1 values were significantly higher in the MACE group compared to the no-MACE group (1,106.0 ± 55.03 ms vs. 1,069.41 ± 46.8 ms, p = 0.007). ROC analysis identified a septal T1 value of 1,082.8 ms as the optimal threshold (sensitivity: 73.91%, specificity: 63.16%). On multivariable regression analysis, native septal T1 remained an independent predictor of MACE (odds ratio = 4.2, 95% confidence interval: 1.01–18.07, p = 0.04). Among 30 LGE-negative patients, 11 (36.7%) had elevated septal T1 values above the cut-off, indicating additional risk stratification capability. Conclusion Native septal T1 mapping provides independent prognostic information in NIDCM patients beyond LGE. It identifies high-risk patients even in the absence of focal fibrosis, offering incremental value for risk-stratification and clinical decision-making. Advances in Knowledge Native T1 mapping independently predicts MACE beyond ejection fraction and LGE. One in three LGE-negative patients demonstrate high-risk diffuse disease, highlighting complementary roles of these techniques.