TY - JOUR
T1 - Relation between myocardial oxygen consumption and myocardial blood volume
T2 - A study using myocardial contrast echocardiography
AU - Le, D. Elizabeth
AU - Bin, Jian Ping
AU - Coggins, Matthew P.
AU - Wei, Kevin
AU - Lindner, Jonathan R.
AU - Kaul, Sanjiv
N1 - Funding Information:
Supported in part by a grants from the National Institutes of Health (3R01-HL-48890), Bethesda, Md, and Bracco Research S.A., Geneva, Switzerland. Phillips Ultrasound, Andover, Mass, provided an equipment grant. Supported by a postdoctoral training grant (HL-07355) from the National Institutes of Health (D.E.L.) and a medical student research grant from the American Diabetes Association, Washington, DC (M.P.C.). K.W. and J.R.L. are recipients of Mentored Clinical Scientist Development Awards (K08-HL03909 and K08-HL03810) from the National Institutes of Health.
PY - 2002/9
Y1 - 2002/9
N2 - Myocardial blood volume (MBV) is the volume of blood residing in myocardial vessels, 90% of which is in capillaries. MBV can be measured in vivo using myocardial contrast echocardiography (MCE). It has been shown that when increases in coronary blood flow (CBF) are not associated with increase in myocardial oxygen consumption (MVO2), MBV does not increase. We hypothesized that MBV would increase when increases in CBF are associated with an increase in MVO2. The atrioventricular node was ablated in 18 dogs and dual-chamber pacing was instituted. In group 1 dogs (n = 9), heart rate was altered from 50 to 150 bpm-1 in increments of 20 bpm-1 in random order. In group 2 dogs (n = 9), heart rate was kept constant, and dobutamine was infused at doses of 5, 10, 20, 30, and 40 μg/kg-1/min-1. During each intervention, hemodynamic parameters and MVO2 were measured, and MCE was performed. MVO2 increased more (P < .01) with inotropic compared with chronotropic stimulation, resulting in a parallel increase in CBF. MBV fraction and MCE-derived myocardial blood flow increased significantly with increases in MVO2 (P < .05 and P < .001, respectively) when dobutamine was infused, but remained unchanged when heart rate alone was increased. We conclude that when MVO2 is increased substantially, the resulting increase in CBF and MCE-derived myocardial blood flow is mediated, in part, by an increase in MBV. Thus, capillary recruitment plays an important role in the physiologic regulation of CBF. Lack of increase in MBV during dobutamine stress may indicate the presence of coronary stenosis or microvascular disease.
AB - Myocardial blood volume (MBV) is the volume of blood residing in myocardial vessels, 90% of which is in capillaries. MBV can be measured in vivo using myocardial contrast echocardiography (MCE). It has been shown that when increases in coronary blood flow (CBF) are not associated with increase in myocardial oxygen consumption (MVO2), MBV does not increase. We hypothesized that MBV would increase when increases in CBF are associated with an increase in MVO2. The atrioventricular node was ablated in 18 dogs and dual-chamber pacing was instituted. In group 1 dogs (n = 9), heart rate was altered from 50 to 150 bpm-1 in increments of 20 bpm-1 in random order. In group 2 dogs (n = 9), heart rate was kept constant, and dobutamine was infused at doses of 5, 10, 20, 30, and 40 μg/kg-1/min-1. During each intervention, hemodynamic parameters and MVO2 were measured, and MCE was performed. MVO2 increased more (P < .01) with inotropic compared with chronotropic stimulation, resulting in a parallel increase in CBF. MBV fraction and MCE-derived myocardial blood flow increased significantly with increases in MVO2 (P < .05 and P < .001, respectively) when dobutamine was infused, but remained unchanged when heart rate alone was increased. We conclude that when MVO2 is increased substantially, the resulting increase in CBF and MCE-derived myocardial blood flow is mediated, in part, by an increase in MBV. Thus, capillary recruitment plays an important role in the physiologic regulation of CBF. Lack of increase in MBV during dobutamine stress may indicate the presence of coronary stenosis or microvascular disease.
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U2 - 10.1067/mje.2002.121275
DO - 10.1067/mje.2002.121275
M3 - Article
C2 - 12221400
AN - SCOPUS:0036739831
SN - 0894-7317
VL - 15
SP - 857
EP - 863
JO - Journal of the American Society of Echocardiography
JF - Journal of the American Society of Echocardiography
IS - 9
ER -