Native T value in the remote myocardium is independently associated with left ventricular dysfunction in patients with prior myocardial infarction.

Purpose: To compare remote myocardium native T in patients with chronic myocardial infarction (MI) and controls without MI and to elucidate the relationship of infarct size and native T in the remote myocardium for the prediction of left ventricular (LV) systolic dysfunction after MI.

Materials And Methods: A total of 41 chronic MI (18 anterior MI) patients and 15 age-matched volunteers with normal LV systolic function and no history of MI underwent cardiac magnetic resonance imaging (MRI) at 1.5T. Native T map was performed using a slice interleaved T mapping and late gadolinium enhancement (LGE) imaging. Cine MR was acquired to assess LV function and mass.

Results: The remote myocardium native T time was significantly elevated in patients with prior MI, compared to controls, for both anterior MI and nonanterior MI (anterior MI: 1099 ± 30, nonanterior MI: 1097 ± 39, controls: 1068 ± 25 msec, P < 0.05). Remote myocardium native T moderately correlated with LV volume, mass index, and ejection fraction (r = 0.38, 0.50, -0.49, respectively, all P < 0.05). LGE infarct size had a moderate correlation with reduced LV ejection fraction (r = -0.33, P < 0.05), but there was no significant association between native T and infarct size. Native T time in the remote myocardium was independently associated with reduced LV ejection fraction, after adjusting for age, gender, infarct size, and comorbidity (β = -0.34, P = 0.03).

Conclusion: In chronic MI, the severity of LV systolic dysfunction after MI is independently associated with native T in the remote myocardium. Diffuse myocardial fibrosis in the remote myocardium may play an important pathophysiological role of post-MI LV dysfunction.

Level Of Evidence: 1 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017;46:1073-1081.