Background: Recent advances in real-time three-dimensional echocardiography (RT3DE) offer the potential to assess the left ventricular (LV) dyssynchrony simultaneously by analyzing the 17 segments time-volume curves. The purpose of this study was to test the feasibility and accuracy of RT3DE for quantitative evaluation of left ventricular systolic synchronicity.
Methods: Twenty-four patients with dilated cardiomyopathy (DCM) and twenty-five healthy volunteers were enrolled in this study. Full volume RT3DE was performed by using Philips IE33 with X3-1 probe. The global and 17-segmental time-volume curves were obtained by the on-line Qlab software (version 4.2). The time to minimal systolic volume in each segment (T(msv)) was taken to derive the following indexes of systolic asynchrony: T(msv) 16-SD, T(msv) 16-Dif, T(msv) 12-SD, T(msv) 12-Dif, T(msv) 6-SD and T(msv) 6-Dif, which meant the standard deviation or the maximal difference of T(msv) among the 16, 12 and 6 segments of the left ventricle respectively. The software also provided with each of the above parameters as a percentage of the cardiac cycle.
Results: T(msv) 16-SD, T(msv) 12-SD and T(msv) 6-SD were all significantly larger in the DCM group than those of the control group [T(msv) 16-SD: (52.9 +/- 40.6) ms vs (8.8 +/- 6.2) ms; T(msv) 12-SD: (29.5 +/- 30.8) ms vs (6.9 +/- 4.0) ms; T(msv) 6-SD: (28.9 +/- 34.6) ms vs (7.0 +/- 4.7) ms, all P < or = 0.001]. T(msv) 16-Dif, T(msv) 12-Dif and T(msv) 6-Dif were also significantly larger in the DCM group. There were close negative relations between the LVEF determined by RT3DE and each of the indexes of systolic asynchrony, among which the indexes of T(msv)-16-SD% and T(msv)-16-Dif% correlated most closely (r = -0.703 and r = -0.701, respectively). The DCM patients had significantly larger EDV and ESV, with significantly reduced LVEF compared with the healthy subjects.
Conclusion: RT3DE provides a simple, useful and unique approach to assess the systolic synchronicity of all the left ventricular segments simultaneously.