ISSN:
1432-2013
Keywords:
Mass spectrometry
;
Subendocardium
;
Subepicardium
;
PO2
;
PCO2
;
Coronary blood flow
;
Coronary occlusion
;
Reactive hyperemia
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract Mass spectrometry was used for the continuous, simultaneous and quantitative measurement of oxygen (PO2) and carbon dioxide (PCO2) partial pressures in the subendocardial and subepicardial layers of the left ventricle in 11 anaesthetized ventilated dogs. Under control conditions,PO2 was significantly lower in the subendocardium (13.5±4.5 mm Hg) than in the subepicardium (20.7±2.3 mm Hg), whereasPCO2 did not differ significantly (43±8.8 and 51±9.2 mm Hg respectively). These variables were not correlated with blood pressure or coronary blood flow. Subendocardial and subepicardialPO2 decreased less than 5 s after coronary occlusion. These changes were more rapid and severe in the subendocardium. After occlusion for 90 s: subendocardialPO2 was 4.1±6.3 mm Hg while subepicardialPO2 was 6.7±15.0 mm Hg (P〈0.05).PCO2 reached peak values of 56±25 mm Hg subendocardial and 82±22 mm Hg subepicardial at 2.67±0.71 min and 3.43±0.93 min after coronary clamping. A reactive hyperemia occurred after coronary unclamping with different time courses and amplitudes for systolic and diastolic stroke flows whilePO2 recovered with different kinetics. SubendocardialPO2 increased with a lower initial slope, probably in relation with the delay in the diastolic hyperemia. The observed delayed subendocardial hyperoxia, unrelated to the hyperemia, may indicate a delay in the recovery of normal work and metabolism in the inner layers of the myocardium.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00652623
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