Automated function imaging: a new operator-independent strain method for assessing left ventricular function.
BACKGROUND
Speckle tracking is a new technique based on pure 2D grayscale ultrasound acquisition allowing calculation of segmental strains. To facilitate clinical application, speckle tracking has been integrated into the most recent echocardiographic systems for quick, automated evaluation of left ventricular function (Automated Function Imaging, AFI).


OBJECTIVE
To evaluate the feasibility, calculation time, accuracy and reproducibility of global longitudinal strain (GLS) from AFI in determining LV function in comparison to reference echocardiographic and angiographic methods-whatever the operator's experience.


METHODS
Echocardiography was performed in 65 patients scheduled for cardiac catheterization using a Vivid 7 system. They were divided into 3 groups according to EF (>55%, 35< or =EF< or =55%,<35%). Image quality, global LV function parameters (ejection fraction, aortic flow, dp/dt) and segmental contraction were analyzed by one experienced operator and one beginner. GLS was obtained from apical 2, 3 and 4 chamber views. GLS was compared to both echocardiographic and angiographic EF, as well as to other echocardiographic parameters.


RESULTS
GLS was obtained successfully in 97% of patients. Mean calculation time including correction of endocardial detection was less than 60 seconds. GLS was significantly different between the 3 groups, respectively -18.1+/-2.5%, -11.5+/-2.1% and -6.0+/-1.2% (p<0.01). Strong correlations were observed between GLS and LV function (r from 0.68 to 0.87) with a high level of reproducibility. No difference was observed between experienced and inexperienced operators.


CONCLUSIONS
AFI is clinically applicable and an effective means of assessing LV function due to its short acquisition time, feasibility and accuracy, whatever the experience of the operator.
Belghitia
H
H
Département de chirurgie cardiaque, Hôpital Cardiologique du Haut-Lévêque, Avenue de Magellan, Pessac.
Brette
S
S
Lafitte
S
S
Reant
P
P
Picard
F
F
Serri
K
K
Lafitte
M
M
Courregelongue
M
M
Dos Santos
P
P
Douard
H
H
Roudaut
R
R
DeMaria
A
A
D000792:Angiography / Q000379:methods*; D001783:Blood Flow Velocity / Q000502:physiology; D002311:Cardiomyopathy, Dilated / Q000175:diagnosis / Q000503:physiopathology*; D003327:Coronary Disease / Q000175:diagnosis / Q000503:physiopathology*; D003952:Diagnostic Imaging / Q000379:methods*; D004452:Echocardiography / Q000379:methods*; D001330:Electronic Data Processing / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D015203:Reproducibility of Results; D013318:Stroke Volume / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology*