Heart failure
Usefulness of Three-Dimensional Speckle Tracking Strain to Quantify Dyssynchrony and the Site of Latest Mechanical Activation

https://doi.org/10.1016/j.amjcard.2009.09.010Get rights and content

Previous methods to quantify dyssynchrony could not determine regional 3-dimensional (3-D) strain. We hypothesized that a novel 3-D speckle tracking strain imaging system can quantify left ventricular (LV) dyssynchrony and site of latest mechanical activation. We studied 64 subjects; 54 patients with heart failure were referred for cardiac resynchronization therapy (CRT) with an ejection fraction 25 ± 6% and QRS interval 165 ± 29 ms and 10 healthy volunteer controls. The 3-D speckle tracking system determined radial strain using a 16-segment model from a pyramidal 3-D dataset. Dyssynchrony was quantified as maximal opposing wall delay and SD in time to peak strain. The 3-D analysis was compared to standard 2-dimensional (2-D) strain datasets and site of 3-D latest mechanical activation, not possible by 2D was quantified. As expected, dyssynchrony in patients on CRT was significantly greater than in controls (maximal opposing wall delay 316 ± 112 vs 59 ± 12 ms and SD 124 ± 48 vs 28 ± 11 ms, p <0.001 vs normal). The 3-D opposing wall delay was closely correlated with 3-D 16-segment SD (r = 0.95) and 2-D mid-LV strain (r = 0.83) and SD (r = 0.85, all p values <0.001). The 3-D site of the latest mechanical activation was most commonly midposterior (26%), basal posterior (22%), midlateral (20%), and basal lateral (17%). Eleven patients studied after CRT demonstrated improvements in 3-D synchrony (300 ± 124 to 94 ± 37 ms) and ejection fraction (24 ± 6% to 31 ± 7%, p <0.05). In conclusion, 3-D speckle tracking can successfully quantify 3-D dyssynchrony and site the latest mechanical activation. This approach may play a clinical role in management of patients on CRT.

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Methods

The study group consisted of 67 subjects, 57 patients with HF referred for CRT and 10 healthy volunteers as normal controls. This protocol was approved by the institutional review board on biomedical research and all subjects gave informed consent consistent with this protocol. The study group consisted of 54 patients with HF after 3 (5%) were excluded from analysis because of poor echocardiographic windows. All patients had HF functional class III, with an ejection fraction (EF) ≤35% and QRS

Results

Overall, 3-D speckle tracking radial dyssynchrony analysis was possible in 963 of 1,024 attempted segments (94%) from the 64 subjects with overall technically adequate images. The total time for 3-D speckle tracking dyssynchrony analysis was approximately 4 to 7 minutes per patient. As expected, 3-D speckle tracking dyssynchrony in patients with HF was significantly greater than that in controls (maximal opposing wall delay 316 ± 112 vs 59 ± 12 ms and SD 124 ± 48 vs 28 ± 11 ms, p <0.001 vs

Discussion

This is the first study to use a novel 3-D speckle tracking echocardiographic system to quantify LV dyssynchrony and site of latest mechanical activation. The 3-D speckle tracking radial strain was feasible in the large majority of consecutive patients studied. It quantified dyssynchrony in patients on CRT to be significantly greater than that in controls, as expected. There was a close correlation between the 2-D– and 3-D–derived speckle tracking radial dyssynchrony indexes. In addition, the

Acknowledgment

The authors are grateful for the support of the entire staff of the echocardiography and electrophysiology laboratories of the University of Pittsburgh Presbyterian University Hospital, Pittsburgh, Pennsylvania.

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This study was supported in part by National Heart, Lung, and Blood Institute Award 2 K24 HL004503-06 from the National Institutes of Health, Bethesda, Maryland, and a research grant from Toshiba Medical Corporation, Tokyo, Japan.

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