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Simultaneous cardiac mechanics and phosphorus‐31 NMR spectroscopy during myocardial ischemia and reperfusion in the intact dog
Author(s) -
Miller D. Douglas,
Salinas Felix,
Walsh Richard A.
Publication year - 1991
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.1910170109
Subject(s) - phosphocreatine , ischemia , medicine , ejection fraction , contractility , cardiology , chemistry , energy metabolism , heart failure
To investigate the high‐energy phosphate metabolic correlates of left ventricular (LV) dysfunction during the onset and recovery from severe, global myocardial ischemia in vivo , seven preinstrumented closed‐chest dogs had ECG‐gated phosphorus‐31 ( 31 P) NMR‐spectroscopy (NMR‐S) studies performed and LV micromanometer and sonomicrometer data measured before, during, and every 5 min following severe occlusive global myocardial ischemia. Ischemic LV + dP / dt max fell from 2396 ± 576 mm Hg/s at baseline to 2185 ± 478 mm Hg/s ( p < 0.05) and did not normalize until after 30 min of reperfusion. LV ejection fraction (EF) decreased significantly (0.32 ± 0.07 EF units to 0.12 ± 0.13 EF units; P < 0.05) and did not recover by 30 min of reperfusion (0.27 ±0.09 units; P < 0.05 vs baseline). Simultaneous 31 P NMR‐S studies demonstrated excellent β ‐ATP signal‐to‐noise (10 ± 4:1). Myocardial acidosis occurred during global ischemia (ApH = −0.22 ± 0.23 units; p < 0.05), with recovery at 30 min of reperfusion. Inorganic phosphate/ phosphocreatine ratio ( P i/PCr) increased significantly during ischemia (0.46 ± 0.07 to 0.61 ± 0.07; P < 0.05), with delayed normalization of this ratio at 30 min of reperfusion. β‐ATP peak area did not change during ischemia. P i /PCr and LV contractility ( + dP/ dt max ) were significantly correlated at baseline ( r = −0.70) and during global ischemia ( r = −0.78; p < 0.01), but not during recovery ( r = 0.006; p = NS). Therefore, the simultaneous evaluation of high‐fidelity hemodynamic data and topical 31 P NMR‐S can be performed in the intact State. © 1991 Academic Press, Inc.