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Background: The response rate to cardiac resynchronization therapy (CRT) may be improved if echocardiographic‐derived parameters are used to guide the left ventricular (LV) lead deployment. Tools to visually integrate deformation imaging and fluoroscopy to take advantage of the combined information are lacking. Methods: An image fusion tool for echo‐guided LV lead placement in CRT was developed. A personalized average 3D cardiac model aided visualization of patient‐specific LV function in fluoroscopy. A set of coronary venography‐derived landmarks facilitated registration of the 3D model with fluoroscopy into a single multimodality image. The fusion was both performed and analyzed retrospectively in 30 cases. Baseline time‐to‐peak values from echocardiography speckle‐tracking radial strain traces were color‐coded onto the fused LV. LV segments with suspected scar tissue were excluded by cardiac magnetic resonance imaging. The postoperative augmented image was used to investigate: (a) registration accuracy and (b) agreement between LV pacing lead location, echo‐defined target segments, and CRT response. Results: Registration time (264 ± 25 seconds) and accuracy (4.3 ± 2.3 mm) were found clinically acceptable. A good agreement between pacing location and echo‐suggested segments was found in 20 (out of 21) CRT responders. Perioperative integration of the proposed workflow was successfully tested in 2 patients. No additional radiation, compared with the existing workflow, was required. Conclusions: The fusion tool facilitates understanding of the spatial relationship between the coronary veins and the LV function and may help targeted LV lead delivery. [ABSTRACT FROM AUTHOR]

There is a need for better methods to quantify regional myocardial function. In the present study, we investigated the feasibility of quantifying regional function in terms of a segmental myocardial work index as derived from strain Doppler echocardiography (SDE) and invasive pressure. In 10 anesthetized dogs, we measured left ventricular (LV) pressure by micromanometer and myocardial longitudinal strains by SDE and sonomicrometry. The regional myocardial work index (RMWI) was calculated as the area of the pressure-strain loop. As a reference method for strain, we used sonomicrometry. By convention, the loop area was assigned a positive sign when the pressure-strain coordinates rotated counterclockwise. Measurements were done at baseline and during volume loading and left anterior descending coronary artery (LAD) occlusion, respectively. There was a good correlation between RMWI calculated from strain by SDE and strain by sonomicrometry (y = 0.73x + 0.21, r = 0.82, P <0.01). Volume loading caused an increase in RMWI from 1.3 ± 0.2 to 2.2 ± 0.1 kJ/m3 (P < 0.05) by SDE and from 1.5 ± 0.3 to 2.7 ± 0.3 kJ/m3 (P = 0.066) by sonomicrometry. Short-term ischemia (1 mm) caused a decrease in RMWI from 1.3 ± 0.2 to 0.3 ± 0.04 kJ/m3 (P < 0.05) and from 1.3 ± 0.3 to 0.5 ± 0.2 kJ/m3 (P < 0.05) by SDE and sonomicrometry, respectively. In the nonischemic ventricle and during short-term ischemia, the pressure-strain loops rotated counterclockwise, consistent with actively contracting segments. Long-term ischemia (3 h), however, caused the pressure-strain loop to rotate clockwise, consistent with entirely passive segments, and the loop areas became negative, -0.2 ± 0.1 and -0.1 ± 0.03 kJ/m3 (P < 0.05) by SDE and sonomicrometry, respectively. A RMWI can be estimated by SDE in combination with LV pressure. Furthermore, the orientation of the loop can be used to assess whether the segment is active or passive. [ABSTRACT FROM AUTHOR]

Objectives: The aim of the study was to compare the ability of the tissue Doppler echocardiographic imaging (TDI) modalities velocity, strain, and displacement to quantify systolic myocardial function. Background: Several TDI modalities may be used to quantify regional myocardial function, but it is not clear how the different modalities should be applied. Methods: In 10 anesthetized dogs we measured left ventricular pressure, longitudinal myocardial velocity, strain, and displacement by TDI at baseline and during left anterior descending coronary artery (LAD) stenosis and occlusion. Reference methods were segmental shortening by sonomicrometry and segmental work. In 10 patients with acute anterior wall infarction (LAD occlusion) and 15 control subjects, velocity, strain, and displacement measurements were performed. Results: In the animal study, systolic strain correlated well with segmental shortening (r = 0.96, p < 0.01) and work (r = 0.90, p < 0.01), and differentiated well between non-ischemic (−13.5 ± 3.2% [mean ± SD]), moderately ischemic (−6.5 ± 2.8%), and severely ischemic myocardium (7.1 ± 13.2%). The ratio post-systolic strain/total strain also differentiated well between levels of ischemia. Displacement and ejection velocity had weaker correlations with segmental shortening (r = 0.92 and r = 0.74, respectively) and regional work (r = 0.85 and r = 0.69), and there was marked overlap between values at baseline and at different levels of ischemia. In the human study, systolic strain differentiated well between infarcted and normal myocardium (1.0 ± 5.0% vs. −17.8 ± 3.8%), whereas systolic displacement (−0.3 ± 1.3 mm vs. −2.3 ± 0.6 mm) and ejection velocity (0.9 ± 0.6 cm/s vs. 2.2 ± 0.6 cm/s) showed overlap. In the infarction group, strain was reduced in segments with infarcted tissue, while systolic velocity and displacement were reduced in all segments and did not reflect the extension of the infarct. Conclusions: Strain was superior to velocity and displacement for quantification of regional myocardial function. Provided technical limitations can be solved, strain Doppler is the preferred TDI modality for assessing function in ischemic myocardium. [Copyright &y& Elsevier]