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A gating 31 P NMR method triggered by pulses for cardiac pacing
Author(s) -
Tanaka Kunio,
Honda Hajime,
Akita Nobuyuki
Publication year - 1992
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.1940050602
Subject(s) - cardiac cycle , phosphocreatine , gating , pulse (music) , nuclear magnetic resonance , chemistry , heart rate , medicine , cardiology , materials science , blood pressure , biophysics , energy metabolism , voltage , physics , biology , quantum mechanics
A new gating NMR technique triggered by pulses for the cardiac pacing of isolated, perfused rat heart is described. This technique is suitable for obtaining spectra at the same positions over the cardiac cycle with the same RF pulse repetition time and with constant heart rate. Accordingly, each recovered magnetization level at these positions during the cycle can be kept constant. It also allows a qualitative analysis of the myocardial energy level during the cycle under the condition of the same or different cardiac workload (rate pressure product, HR X LVP). This method was used to observe cyclical changes in the concentration of adenosine triphosphate (ATP), phosphocreatine (PCr), P i , and in pH during the cardiac cycle, and confirmed that the levels of ATP and PCr showed reversible decreases, and P i showed an antiphasic increase at the peak systole. On the other hand, no significant changes in pH were noted during the cardiac cycle. This pacing‐gated technique is an improvement over other gated NMR techniques triggered by the blood pressure or by ECG traces.