TY - JOUR
T1 - Dependency of contractile reserve on myocardial blood flow
T2 - Implications for the assessment of myocardial viability with dobutamine stress echocardiography
AU - Lee, Hans H.
AU - Dávila-Román, Victor G.
AU - Ludbrook, Philip A.
AU - Courtois, Michael
AU - Walsh, John F.
AU - Delano, Deborah A.
AU - Rubin, Patricia J.
AU - Gropler, Robert J.
PY - 1997/11/4
Y1 - 1997/11/4
N2 - Background: Contractile reserve, improvement in contractile function during inotropic stimulation, is a proposed marker of viable myocardium. This study was designed to address, in patients with left ventricular dysfunction due to chronic coronary artery disease, whether contractile reserve depends on myocardial blood flow. Methods and Results: We studied 19 patients, at rest and during dobutamine, with 2D echocardiography for regional mechanical function and PET for regional myocardiaI blood flow ([15O]water) and oxygen consumption ([11C]acetate). Of 166 myocardial segments, 21 had normal systolic function, 56 were dysfunctional but contractile reserve-positive, and 89 were dysfunctional and contractile reserve-negative. Myocardial blood flow at rest was lower in contractile reserve-negative (0.41±0.18 mL · g- 1 · min-1) than in contractile reserve-positive (0.50±0.22 mL · g-1 · min-1) and normal segments (0.55±0.20 mL · g-1 · min-1, P<.009). After dobutamine infusion, blood flow increased less in contractile reserve- negative (0.63±0.38 mL · g-1 · min-1) than in contractile reserve- positive (1.28±0.65 mL · g-1 · min-1) and normal segments (1.93±0.83 mL · g-1 · min-1, P<.0001). Likewise, myocardial oxygen consumption was lower at rest in contractile reserve-negative (clearance rate of [11C]acetate, 0.043±0.012 min-1) than in contractile reserve-positive (0.048±0.01 min-1) and normal segments (0.058±0.008 min-1, P<.02). Myocardial oxygen consumption with dobutamine increased less in contractile reserve-negative (0.060±0.013 min-1) than in contractile reserve-positive (0.077±0.016 min-1) and normal segments (0.092±0.024 min-1, P<.0001). Of segments defined as viable by PET, 54% were contractile reserve-negative and exhibited lower blood flow with dobutamine (0.72±0.36 mL · g-1 · min-1) than with viable, contractile reserve-positive segments (1.29±0.70 mL · g-1 · min-1, P<.0001). Conclusions: Contractile reserve depends, in part, on the level of myocardial blood flow at rest and during inotropic stimulation.
AB - Background: Contractile reserve, improvement in contractile function during inotropic stimulation, is a proposed marker of viable myocardium. This study was designed to address, in patients with left ventricular dysfunction due to chronic coronary artery disease, whether contractile reserve depends on myocardial blood flow. Methods and Results: We studied 19 patients, at rest and during dobutamine, with 2D echocardiography for regional mechanical function and PET for regional myocardiaI blood flow ([15O]water) and oxygen consumption ([11C]acetate). Of 166 myocardial segments, 21 had normal systolic function, 56 were dysfunctional but contractile reserve-positive, and 89 were dysfunctional and contractile reserve-negative. Myocardial blood flow at rest was lower in contractile reserve-negative (0.41±0.18 mL · g- 1 · min-1) than in contractile reserve-positive (0.50±0.22 mL · g-1 · min-1) and normal segments (0.55±0.20 mL · g-1 · min-1, P<.009). After dobutamine infusion, blood flow increased less in contractile reserve- negative (0.63±0.38 mL · g-1 · min-1) than in contractile reserve- positive (1.28±0.65 mL · g-1 · min-1) and normal segments (1.93±0.83 mL · g-1 · min-1, P<.0001). Likewise, myocardial oxygen consumption was lower at rest in contractile reserve-negative (clearance rate of [11C]acetate, 0.043±0.012 min-1) than in contractile reserve-positive (0.048±0.01 min-1) and normal segments (0.058±0.008 min-1, P<.02). Myocardial oxygen consumption with dobutamine increased less in contractile reserve-negative (0.060±0.013 min-1) than in contractile reserve-positive (0.077±0.016 min-1) and normal segments (0.092±0.024 min-1, P<.0001). Of segments defined as viable by PET, 54% were contractile reserve-negative and exhibited lower blood flow with dobutamine (0.72±0.36 mL · g-1 · min-1) than with viable, contractile reserve-positive segments (1.29±0.70 mL · g-1 · min-1, P<.0001). Conclusions: Contractile reserve depends, in part, on the level of myocardial blood flow at rest and during inotropic stimulation.
KW - Coronary disease
KW - Echocardiography
KW - Myocardial contraction
KW - Tomography
UR - http://www.scopus.com/inward/record.url?scp=0342813048&partnerID=8YFLogxK
U2 - 10.1161/01.CIR.96.9.2884
DO - 10.1161/01.CIR.96.9.2884
M3 - Article
C2 - 9386153
AN - SCOPUS:0342813048
SN - 0009-7322
VL - 96
SP - 2884
EP - 2891
JO - Circulation
JF - Circulation
IS - 9
ER -