A novel echocardiographic index of inefficient left ventricular contraction resulting from mechanical dyssynchrony.
OBJECTIVE
The purpose of this study was to explore the possibility of using our novel echocardiographic index of inefficient left ventricular (LV) contraction in patient selection for cardiac resynchronization therapy (CRT).


METHODS
Forty consecutive patients with LV ejection fraction < or = 35% were divided into 2 groups, 9 CRT candidates and 31 non-CRT candidates based on conventional criteria. A global LV time-area curve and regional LV time-area curves in 6 radial sectors were obtained using two-dimensional echocardiography in the short-axis view with speckle tracking. Fractional inefficient contraction (FIC, %) was calculated as follows: (1-global LV area change/sum of regional LV area changes) x 100. LV dyssynergy and dyssynchrony were quantified as the standard deviations of minimal values of circumferential speckle-tracking strain and their timings in the 6 sectors, respectively.


RESULTS
There was no significant difference in LV dyssynchrony between CRT candidates and non-CRT candidates (79 + or - 61 ms vs. 58 + or - 26 ms, respectively). In contrast, FIC was significantly larger in CRT candidates than in non-CRT candidates (15.7 + or - 11.0% vs. 5.4 + or - 3.5%, respectively, p=0.0018), with less overlap between groups. FIC showed a positive correlation with dyssynchrony (r=0.64) and a negative correlation with dyssynergy (r=-0.42).


CONCLUSIONS
Our novel echocardiographic index of inefficient LV contraction, which increases with more dyssynchrony or less dyssynergy, may prove more useful in patient selection for CRT than other indices that focus on LV temporal dyssynchrony alone.
Abe
Yukio
Y
Department of Cardiology, Osaka City General Hospital, 2-13-22 Miyakojima-hondori, Miyakojima-ku, Osaka 534-0021, Japan. abeyukio@aol.com
Yagishita
Daigo
D
Tagawa
Yoshimi
Y
Furukawa
Atsuko
A
Nakagawa
Eiichiro
E
Yunoki
Kei
K
Shirai
Naoya
N
Komatsu
Ryushi
R
Naruko
Takahiko
T
Yoshiyama
Minoru
M
Yoshikawa
Junichi
J
Haze
Kazuo
K
Itoh
Akira
A
D000368:Aged; D002304:Cardiac Pacing, Artificial; D004452:Echocardiography / Q000379:methods; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018487:Ventricular Dysfunction, Left / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy