title: Myocardial blood flow and VO2 in conscious lambs with an aortopulmonary shunt.
abstract: We measured myocardial blood flow (QLVFW) and O2 consumption of the left ventricular free wall (VO2, LVFW) in 13 chronically instrumented, 7-wk-old lambs with an aortopulmonary left-to-right shunt (S) and in 10 control lambs without a shunt (C). The measured VO2, LVFW was compared with the calculated values obtained by two predictive indexes, the rate-pressure product (RPP) and the pressure-work index (PWI). Measured VO2, LVFW in S lambs was significantly higher than in C lambs [983 +/- 104 (SE) vs. 475 +/- 57 mumol X min-1 X 100 g LV-1, P less than 0.001]. This was achieved by the significantly higher QLVFW (294 +/- 33 vs. 145 +/- 15 ml X min-1 X 100 g LV-1, P less than 0.002), since the arteriovenous O2 difference across the left ventricular free wall was similar in both groups of lambs. Total coronary blood flow per unit body mass in S lambs was higher than in C lambs (14.1 +/- 1.5 vs. 5.6 +/- 0.6 ml X min-1 X kg-1, P less than 0.001), not only because of the increased VO2, LVFW per unit muscle mass, but also because of the increased total heart weight (102.4 +/- 6.4 vs. 81.2 +/- 4.9 g, P less than 0.02). Correct estimation of VO2, LVFW by means of the RPP and the PWI was only possible in C lambs. In S lambs the estimated values were significantly lower than the measured ones.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000818:Animals; D001011:Aorta; D001159:Arterio-Arterial Fistula; D001794:Blood Pressure; D002302:Cardiac Output; D003326:Coronary Circulation; D006321:Heart / Q000033:anatomy & histology; D006339:Heart Rate; D009206:Myocardium / Q000378:metabolism*; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption; D011651:Pulmonary Artery; D012039:Regional Blood Flow; D012756:Sheep; D013318:Stroke Volume
chemical_list: D010100:Oxygen