Noninvasive, quantitative assessment of left ventricular function in ischemic cardiomyopathy.
BACKGROUND
Coronary artery disease characteristically impacts left ventricular (LV) function on a regional basis, although ultimately global function may be affected as well. Echocardiography is commonly clinically used for the assessment of regional function; however, it is only semiquantitative and in its current iteration is only two-dimensional in nature. Magnetic resonance imaging (MRI) with tissue tagging offers the possibility for noninvasive, three-dimensional (3D) assessment of transmural and segmental left ventricular strain and, thereby, function. Accordingly, we have explored methodologies to accurately and quantitatively characterize regional systolic function in three dimensions in patients with ischemic heart disease using MRI.


METHODS
MRI radiofrequency tissue tagging was performed at rest and during dobutamine administration (10 mg/kg/min) on 10 normal volunteers (age: 26 +/- 6) and 8 patients with severe ischemic cardiomyopathy (age: 60 +/- 5, EF 26 +/- 11%). Three-dimensional global and regional systolic strain calculations were made based on 3D myocardial point displacements and compared with conventional measures.


RESULTS
Global left ventricular strains were significantly decreased in ischemic patients at rest (0.14 +/- 0.04 versus 0.25 +/- 0.02, P < 0.001) and with dobutamine (0.14 +/- 0.03 versus 0.29 +/- 0.03, P < 0.001). In the regional analysis (216 LV wall segments) this methodology accurately differentiated normal from abnormally contracting regions.


CONCLUSIONS
Noninvasive dobutamine MRI tissue tagging with calculation of 3D regional strains has significant promise as a clinical tool which is capable of the identification, quantification, and display of regionally varying ventricular function.
Moustakidis
Pavlos
P
Department of Surgery, Washington University, St Louis, Missouri, USA.
Cupps
Brian P
BP
Pomerantz
Benjamin J
BJ
Scheri
Randall P
RP
Maniar
Hersh S
HS
Kates
Andrew M
AM
Gropler
Robert J
RJ
Pasque
Michael K
MK
Sundt
Thoralf M
TM
D000368:Aged; D002316:Cardiotonic Agents; D016022:Case-Control Studies; D004280:Dobutamine; D005260:Female; D006801:Humans; D021621:Imaging, Three-Dimensional; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D017202:Myocardial Ischemia / Q000175:diagnosis* / Q000503:physiopathology*; D013314:Stress, Mechanical; D016277:Ventricular Function, Left
D002316:Cardiotonic Agents; D004280:Dobutamine