Abstact
The function of Left atrium(LA) is difficult to assess because of its ventricle-dependent, dynamic movement as systolic distension, early diastolic contraction and late diastolic atrial kick. Velocity Vector Imaging(VVI) is a newer technique which is angle-independent and thus provides a more precise avenue to evaluate LA function. We tried to assess the LA function precisely in each systolic and diastolic phase in hypertrophic cardiomyopathy(HCMP), left ventricular hypertrophy(LVH) and normal group.
Methods
18 patients with HCMP(72.2% of male, mean age of 52.6 ± 9.8), 15 patients with LVH(87.5% of male, mean age of 54.0 ± 15.3) and 10 age-matched controls(83.3% of male, mean age of 50.0 ± 4.6) were studied. Echocardiographic images of LA in apical 2 and 4 chamber views were analyzed by conventional manual tracing by novel software(Axius Velocity Vector Imaging). We compared the peak velocity, strain and strain rate among the groups to assess the left atrial dynamics.
Results
The baseline systolic function, LA size and E velocity are not different in three groups. The E’ velocity (normal:LVH:HCMP = 7.7±1.07 : 5.1±0.75 : 4.5±1.31 cm/sec, p=0.013), E/E’(normal:LVH:HCMP = 6.8 ± 1.60 : 12.4 ± 3.27 : 14.7 ± 4.18, p=0.035) and and late diastolic SR at mid LA(normal:LVH:HCMP = -1.65±0.51: -0.97±0.55 : -0.82±0.32, p=0.002) are significantly different in each groups.
The mean late diastolic peak strain rate of mid LA are significantly correlated with E/E’(r=0.383 p=0.037), E’(r=-0.453 p=0.012) and LA size(r=0.407 p= 0.025). The indices in systolic and early diastolic phase are not significantly different each other and those of base are so diverse because of annular motion. Other velocity and strain are not significantly correlated with these variables.
Conclusion
The late diastolic(atrial kick) peak strain rate of mid LA is significantly different in three groups. They are correlated well with E/E’, E’ and LA size. The more contractile mid LA, the better LA function as we think. The Velocity Vector Imaging(VVI) is another new technique which can precisely assess the LA function.
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