Annular excursion contributes to efficient cardiac output: a three-dimensional echocardiographic approach.
OBJECTIVE
The heart produces an efficient cardiac output by repeating diastole and systole. With the evolution of three-dimensional (3D) echocardiography, it is possible to evaluate cardiac motion using detailed 3D morphologic echocardiography. The study aim was to evaluate mitral and aortic annulus excursions towards the apex of the left ventricle, using 3D echocardiography. Measurements of the angle variation between the mitral and aortic valve throughout the cardiac cycle were performed to determine the effects of annulus excursion on cardiac function.


METHODS
Seven healthy adolescents (five males, two females; mean age 15.9 +/- 1.1 years; Group H) and seven patients with dilated cardiomyopathy (seven males; mean age 63.6 +/- 12.9 years; Group D) were selected. All subjects underwent 3D echocardiography between November 2007 and June 2008. Annulus excursion (AE) was defined as the annular motion towards the apex. The Ex-Ratio A (%) and Ex-Ratio M (%) were defined as the ratios of aortic or mitral excursion, respectively, to the maximal distance from the annulus to the left ventricular apex. The annulus was defined simply as a flat round disc, and the annular area calculated as the annular distance between the anterior and posterior annulus as a circle diameter. The annulus excursion volume (AEV) was calculated by multiplying the annular area by AE, and determined for each valve of each patient. The total AEV was the summation of the mitral and aortic AEVs. The ratio of AEV to left ventricular diastolic volume was expressed as AEV/EDV. Angular variation between the valves was measured during the cardiac cycle with the following values: maximal angle (Dmax), minimal angle (Dmin), and the difference between Dmax and Dmin (Dmax-min).


RESULTS
In all cases, the apex was in a fixed position. The AE was significantly greater for group H than for group D. While AEV did not differ between groups, AEV/EDV(A) and AEV/EDV(M) were greater for group H than for group D. The angle between the mitral and aortic annulus changed throughout the cardiac cycle. The Dmax-min value was significantly greater for group H than for group D.


CONCLUSIONS
Annulus excursion contributes to an efficient cardiac output. The angle variation was measured during the cardiac cycle and found to be greater in healthy adolescents. 3D echocardiography represents a useful modality for clarifying 'motional cardiac morphology'.
Sughimoto
Koichi
K
Department of Cardiovascular Surgery, Funabashi Municipal Medical Center, Chiba, Japan. ksughimoto@yahoo.co.jp
Takahara
Yoshiharu
Y
Mogi
Kenji
K
Liu
Hao
H
Yamazaki
Kenji
K
D000293:Adolescent; D001021:Aortic Valve / Q000000981:diagnostic imaging* / Q000502:physiology*; D002302:Cardiac Output; D002311:Cardiomyopathy, Dilated / Q000000981:diagnostic imaging / Q000503:physiopathology; D019560:Echocardiography, Three-Dimensional; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008943:Mitral Valve / Q000000981:diagnostic imaging* / Q000502:physiology*; D009200:Myocardial Contraction