ATP content measured by 31P NMR correlates with post-ischaemic recovery of external work output in an isolated rat heart perfused with erythrocyte suspension.

The limited capacity of the heart to survive ischaemia presents a recognized problem during open-heart surgery. In order to provide a baseline for the study of cardioprotection we subjected a series of isolated rat hearts to periods of ischaemia of increasing duration, and sought correlations between phosphate metabolite levels as measured by 11P NMR and post-ischaemic recovery of external work output. A strong linear correlation was found between the fraction of ATP measured after reperfusion expressed as a ratio. RATP to the pre-ischaemic level, and the fractional recovery of external work output, RW: Rw = 1.06 (SE 0.27) RATP + 0.01 (SE 0.21) (Spearman rank correlation coefficient 0.72, two-tailed P value 0.006).