Gated blood pool tomoscintigraphy with 4-dimensional optical flow motion analysis quantifies left ventricular mechanical activation and synchronization.
BACKGROUND
Gated blood pool tomoscintigraphy has the unique capacity to accurately assess myocardial motion in paced patients. Our goal was to develop a precise radionuclide angiography analysis of cardiac dynamics to evaluate ventricular synchronization in patients undergoing biventricular pacing.


RESULTS
On the basis of a 4-dimensional deformable motion estimation algorithm, we developed a protocol allowing estimation of motion fields after gated blood pool tomoscintigraphy. We measured the mechanical activation times for 17 left ventricular (LV) segments and determined the main types of contraction pattern in 10 normal subjects, 17 patients with dilated cardiomyopathy, and 12 resynchronized patients. We analyzed intra-LV dyssynchrony: apex to base, septum to lateral wall, and anterior wall to inferior wall. Three-dimensional measurements of intra-LV activation time (r > .80, P < .001) and LV ejection fraction (r > 0.90, P < .0001) are linearly correlated to 2-dimensional values. LV contraction follows the electrical activation pattern. In normal subjects the anteroseptal and anterior segments are first activated, followed by the apex and inferolateral segments. In resynchronized patients contraction begins with the lateral and apicoseptal segments in correspondence to the LV and right ventricular lead implantation.


CONCLUSIONS
By measuring mechanical activation times, this technique allows for the analysis of the regional synchronous contraction. This may help to assess the variation of the activation pattern according to the cardiomyopathy type and the role of septal resynchronization in ventricular functional recovery.
Dinu
Claudia
C
Physiology & Radioisotopes Unit, Hôpital Européen Georges Pompidou, Paris, France. claudia.dinu@gmail.com
Klein
Gregory
G
Morestin-Cadet
Sophie
S
Froissart
Marc
M
Diebold
Benoît
B
LeHeuzey
Jean-Yves
JY
Paillard
Michel
M
Lavergne
Thomas
T
Toussaint
Jean-François
JF
D000368:Aged; D001145:Arrhythmias, Cardiac / Q000150:complications / Q000000981:diagnostic imaging* / Q000628:therapy; D009202:Cardiomyopathies / Q000150:complications / Q000000981:diagnostic imaging*; D019560:Echocardiography, Three-Dimensional / Q000379:methods*; D005260:Female; D015637:Gated Blood-Pool Imaging / Q000379:methods*; D006329:Heart Conduction System / Q000000981:diagnostic imaging; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009068:Movement; D009200:Myocardial Contraction; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging* / Q000209:etiology