ISSN:
1432-2013
Keywords:
Cryomicrophotometric oximetry
;
Heterogeneity of tissue perfusion
;
Subendocardial O2 extraction
;
Subepicardial O2 extraction
;
Regional myocardial blood flow
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Summary Oxygen consumption in subendocardial and subepicardial layers of left ventricular myocardium was studied. Oxygen consumption was calculated from regional perfusion data obtained by the microsphere technique and regional O2 extraction derived from intracapillary HbO2 saturation (i.c. HbsO2). I.c. HbsO2 data were obtained cryomicrophotometrically from shock-frozen, transmural tissue specimens removed from thoracotomized dogs. Left ventricular myocardial blood flow at the time of the specimen removal was 63±9 ml/min · 100 g. The ratio of subendocardial to subepicardial blood flow was 1.27 ±0.17. Coronary sinus blood oxygen saturation was 31±2% and left ventricular oxygen consumption was 8.4±1.1 ml/min · 100 g. A mean i.c. HbsO2 of 47±18% was obtained. 23% of all measured i.c. HbsO2 values were lower than the respective coronary sinus value. The mean subendocardial i.c. HbsO2 (41±19%) was significantly lower than the mean subepicardial value (53±16%). From these data a ratio of subendocardial to subepicardial oxygen consumption of 1.57 was calculated. This result is in agreement with recent hypotheses, stating that myocardial fiber shortening and energy demands in deeper layers of left ventricle exceed those of superfical layers.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00585535
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