title: Calibration of the normal cutoff values of systolic dyssynchrony of the left ventricular synchronicity in normal subjects using real-time 3-dimensional echocardiography and the effects of age and heart rate.
abstract: The normal data of left ventricular (LV) synchronicity by real-time 3-dimensional echocardiography (RT3DE) are lacking. We assessed the normal range/cutoff values of LV dyssynchrony parameters by RT3DE. For this purpose, RT3DE was performed in 130 healthy subjects, aged 53 ± 12 years. Time to the point of minimal regional systolic volume (Tmsv) was measured from time-volume curves in each segment. Standard deviation (SD) and maximal difference (Dif) of Tmsv were calculated from 16 (6 basal/6 mid/4 apical), 12 (6 basal/6 mid), and 6 (basal) LV segments together with the corresponding parameters adjusted by R-R interval. The data show non-significant difference between Tmsv-16-SD (9.24 ± 3.54 ms) and Tmsv-12-SD (8.80 ± 3.82 ms); with a correlation between two by both unadjusted (ms; r = 0.87) and adjusted (%R-R; r = 0.84) methods (P < 0.001). Heart rate correlated negatively with Tmsv (r = -0.13 to -0.34, P < 0.05-0.001) but had no effect on parameters adjusted for %R-R. Age and gender did not affect any of these parameters. Inter-observer variability was 3.3-4.6 % for 16, 4.8-9.1 % for 12, and 14.4-19.7 % for 6 segments. Thus, RT3DE is a reliable technique for detecting LV systolic dyssynchrony whereas the heart rate, but not age and gender, affects Tmsv parameters. Dyssynchrony parameters by 16 or 12 segments are superior to 6 segments in yielding comprehensive information and lower variability.
authors.forename: Chun-Yan
authors.initials: CY
authors.lastname: Ma
authors.forename: Shuang
authors.initials: S
authors.lastname: Liu
authors.forename: Qing
authors.initials: Q
authors.lastname: Zhang
authors.forename: Jun
authors.initials: J
authors.lastname: Yang
authors.forename: Li
authors.initials: L
authors.lastname: Tang
authors.forename: Gabriel
authors.initials: G
authors.lastname: Yip
authors.forename: Cheuk-Man
authors.initials: CM
authors.lastname: Yu
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D019560:Echocardiography, Three-Dimensional / Q000592:standards*; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015588:Observer Variation; D012016:Reference Values; D015203:Reproducibility of Results; D012737:Sex Factors; D013599:Systole / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology*