Reproducibility of coronary haemodynamics and cardiac metabolism during pacing-induced XXXX .

@entity1 @entity2227 @entity1792 @entity26 @entity951 @entity880 @entity453 @entity1718 @entity493 @entity413
The reproducibility of coronary sinus blood flow (CSBF) (thermodilution technique) and myocardial metabolism (exchange of @entity26 , @entity880 , free @entity1718 , @entity413 , @entity1792 , @entity2227 and @entity493 ) during two identical pacing periods separated by 45 min were studied in eight @entity1 with chronic @entity453 . The mean of the individual difference (delta-values) between values during the first (T1) and second (T2) test, at corresponding times (rest, pacing and after 3-5 min of recovery), were calculated and expressed as a percentage of the resting level of each parameter in order to assess their reproducibility. All @entity1 experienced @entity951 during both pacing sessions, and pacetime to onset of symptoms did not differ between the tests. Group values for haemodynamics and exchange of metabolites were acceptably reproducible throughout the period under study. Mean delta-values of CSBF ranged from 10% to 16% and myocardial @entity26 uptake from 14% to 22% in relation to the resting levels. In contrast, mean delta-values of metabolites ranged from 5% to 136% in relation to the respective A-V differences during the study. The greatest variation occurred during pacing and of all the metabolites @entity880 exchange varied most. A spontaneous variation in the degree of ischaemia during repeat stress tests might be the major reason for the metabolite variability. Changes in CSBF, however, tended to correlate inversely to the delta-aortocoronary sinus differences of substrates during pacing. Precision of chemical analysis and blood sampling technique were of minor importance for the variability. Since @entity880 exchange varied most, the study suggests that additional measurements should be made of more metabolites when assessing the efficacy of therapy by means of myocardial metabolism.
