The addition of Pi/PCr quantification adds value over PCr/ATP for the characterisation of myocardial energetics. In defining the chemical shift of the Pi resonance, pH can also be computed. Such measurements however are hampered in 31P MRS due to the overlapping 2,3-DPG resonance. In harnessing the black blood contrast offered by STEAM, we successfully characterise Pi (and hence myocardial pH) in a cohort of patients with dilated cardiomyopathy. We go on to shown that in these patients (but not controls) Pi/PCr rises significantly during dobutamine stress, a finding that would significantly impair the free energy of ATP hydrolysis during exertion.