Abstract 18676: Association of Myocardial T1 Relaxation Properties With Left Ventricular Diastolic Function and Hemodynamic Change in Ambulatory Stable Patients With Non-ischemic Cardiomyopathy
Introduction: Myocardial extracellular volume expansion determined by cardiac MRI is a marker of myocardial fibrosis. In this study we sought to determine the association between T1 indices and left ventricular (LV) diastolic function evaluated by echocardiography and hemodynamic change by brain natriuretic peptide (BNP) in ambulatory patients with non-ischemic cardiomyopathy (CM).
Methods: All participants were recruited prospectively to undergo cardiac MRI and echocardiography. Myocardial T1 was assessed on T1 maps using shortened modified look-locker inversion recovery sequence before and 15 minutes after the administration of gadolinium contrast. T1 indices were derived from the averaged T1 value of the LV basal and mid slices and included native and post-contrast myocardial T1, partition coefficient and extracellular volume fraction (ECV). Hematocrit, BNP and NT-BNP were measured.
Results: Compared to the normal controls (N=14), native myocardial T1, partition coefficient and ECV were higher in CM patients (N=31) 1013±74 ms vs. 959±35 ms, (p=0.002), 0.47±0.06 vs 0.43±0.03 (p=0.018), and 0.24±0.03 vs. 0.28±0.04 (p=0.038), respectively while post contrast T1 was not significantly different. Using Pearson’s correlation, increased native T1, partition coefficient and ECV were significantly associated with increased E/A ratio 0.527 (p=0.001), 0.314 (p=0.066), 0.340 (p=0.042) respectively, and mitral medial E/e’ 0.497 (p=0.001), 0.295 (0.009) and 0.403 (p=0.016) respectively. The association was greater with BNP and NT pro-BNP (logarithm transformed) 0.523 (p<0.001), 0.387 (p=0.014), 0.448 (p=0.003), respectively, and 0.611 (p<0.001), 0.558 (p<0.001) and 0.642 (p<0.001), respectively. There was no significant correlation of diastolic indices or BNP with post contrast T1. Multivariate regression analyses confirmed univariate findings.
Conclusion: Of the four commonly used T1 indices, increased native T1, partition coefficient and ECV were significantly associated with altered LV diastolic function and increased BNP. Our findings demonstrate the importance of noninvasive tissue characterization by CMR in understanding abnormal LV diastolic function and subsequent hemodynamic change in patients with non-ischemic CM
Author Disclosures: N. Choudhary: None. L. Duncanson: None. R.S. Toole: None. E. Barasch: None. J.J. Cao: None.
- © 2014 by American Heart Association, Inc.