Flow-function relationships in chronic left-ventricular ischemic dysfunction: Impact of the transmurality of infarction.
BACKGROUND
We examined flow-function relationships in humans with chronic coronary artery disease (CAD) in relation to the transmural extent of necrosis, aiming to distinguish the various pathophysiologic conditions that cause chronic ischemic dysfunction, ie, chronic hibernation (perfusion-contraction match) from chronic stunning (perfusion-contraction mismatch).


RESULTS
Twenty-two patients (18 men, 61 +/- 13 years) with CAD and chronic contractile dysfunction (ejection fraction, 26% +/- 13%) and 6 volunteers underwent tagged and gadolinium (Gd)-DTPA contrast-enhanced magnetic resonance imaging as well as (13)NH(3)-positron emission tomography. The relationship between regional circumferential shortening strain (ECC), transmural necrosis, and absolute transmural myocardial perfusion (MBF) was examined quantitatively in dysfunctional segments (<10% ECC). Noninfarcted (<25% transmurality), dysfunctional myocardium presented a perfusion-contraction mismatch, as indicated by a 72% reduction (to -5% +/- 4% shortening) of ECC, versus only a 12% (to 63 +/- 20 mL/min/100 g) reduction of transmural MBF. With increasing amounts of necrosis, reductions between perfusion versus contraction became increasingly matched, ie, dysfunctional segments with a greater than 75% transmural extent of necrosis had a 57% reduction of MBF (to 30 +/- 17 mL/min/100 g), for a similar severe reduction of 80% of ECC (to -3% +/- 3% shortening).


CONCLUSIONS
Noninfarcted, dysfunctional human myocardium mostly presents with a perfusion-contraction mismatch, consistent with stunning. By contrast, dysfunctional myocardium presenting with a perfusion-contraction match is always associated with significant amounts of necrosis.
Division of Cardiology, Cliniques Universitaires St. Luc, Université Catholique de Louvain, Brussels, Belgium. bernhard.gerber@clin.ucl.ac.be
Bernhard L
BL
Gerber
Ho Thien
HT
Thanh
Véronique
V
Roelants
Agnès
A
Pasquet
David
D
Vancraeynest
Jean-Louis J
JL
Vanoverschelde
D001783:Blood Flow Velocity; D003326:Coronary Circulation; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000150:complications / Q000503:physiopathology*; D018487:Ventricular Dysfunction, Left / Q000150:complications / Q000503:physiopathology*