Background : To evaluate left ventricular (LV) asynchrony with volume-time curves (VTC) of 16 segments using real-time three dimensional echocardiography (RT3DE) and to compare with tissue Doppler imaging (TDI).
Methods: Ten patients with LV dysfunction (ejection fraction; EF : 27 ± 8 %, mean age ; 62 ± 14 years) and 10 normal controls (EF : 62 ± 4 %, mean age : 40 ± 11 years) underwent RT3DE. In each subject, VTCs of 16 segments were generated with 3D computer software (4D LV analysis, TomTec) (Figure). The time that LV volume reached to end systolic volume on VTC was defined as end systolic time (EST).
ESTs of all subjects were adjusted by their heart rate and defined as corrected EST in percentage (cEST = EST*100/cardiac cycle length). Asynchrony was determined by standard deviation of cESTs of 16 segments. TDI analysis for measurement of electro-
mechanical coupling time of LV was performed in 8 segments (base and mid LV walls). LV asynchrony with TDI was determined by maximal difference between the longest and the shortest electromechanical coupling time.
Results: There was no significant difference of QRS duration between patients with LV dysfunction and controls (84.0 ± 21.7 vs 79.0 ± 21.3 msecs, p = 0.61). Standard deviation of cEST was significantly larger in patients with LV dysfunction than in controls (8.1 ± 2.4 vs 1.4 ± 0.7 %, p < 0.01). Maximal difference of electromechanical coupling time was also significantly larger than controls (70.5 ± 27.1 vs 32.0 ± 14.0 msecs, p < 0.01) and showed negative correlation with LVEF (r = -0.69, p < 0.01). Standard deviation of cEST revealed a significant negative correlation with LVEF (r = - 0.91, p < 0.01) and was well correlated with maximal difference of electromechanical coupling time (r = 0.93, p <0.01).
Conclusions: We suggest that standard deviation of cEST from VTCs of 16 segments may be a useful parameter to estimate asynchrony of whole LV chamber.
|
