Extra-cellular volume (ECV) mapping using combined native and post-contrast myocardial T1 maps shows promise in assessing cardiomyopathies. However, its feasibility for full left ventricular (LV) coverage is limited using conventional myocardial T1 mapping techniques such as modified Look-Locker inversion recovery (MOLLI) with single-slice acquisition per breathhold. The previously proposed fast single-breathhold 2D multi-slice myocardial T1 mapping (FAST1) technique can provide time-efficient full LV coverage. In this work, its capability for ECV mapping with full LV coverage at 1.5T is evaluated. Compared to MOLLI, FAST1 yields 4-fold increased spatial coverage, limited penalty of ECV spatial variability and highly correlated ECV values.