Abstract 16508: Fusion of 3D Echocardiography and Computed Tomography for Optimization of Cardiac Resynchronization Therapy
Introduction: A high percentage of patients do not respond to cardiac resynchronization therapy (CRT), because the left ventricular (LV) lead is placed too far from the site of late myocardial activation. Optimal lead placement remains problematic, because different imaging modalities are used to depict coronary anatomy with high spatial resolution and LV wall dynamics with high temporal resolution. We hypothesized that fusion of computed tomography (CT) coronary veins with 3D transthoracic echocardiography (TTE) wall motion timing maps is feasible and may allow measurement of the distances between coronary veins and the site of late activation.
Methods: In 9 patients with systolic heart failure (56+8 years, LVEF 34+9%), we obtained 3D full volume TTE of the LV and cardiac CT datasets. Prototype software (TomTec) was used to fuse coronary veins with 3D TTE parametric maps of the timing of LV wall motion superimposed on CT derived 3D endocardial surfaces. Distances were measured between the LV wall with latest activation to the closest and the second closest coronary veins, i.e. optimal and secondary implantation sites.
Results: Fusion of CT coronary veins and parametric maps of the timing of LV wall motion obtained from 3D TTE was possible in all patients. No site of late activation was identified in one patient on 3D TEE. In the remaining 8 patients, measurements from the site of late activation to the optimal and secondary implantation sites were feasible. The measured distances ranged from 3 to 45 mm for the optimal and 21 to 106 mm for secondary implantation sites.
Conclusions: This is the first study to demonstrate the feasibility of 3D fusion of CT anatomy with TTE functional information. This approach allows measurements that may be used to prospectively and noninvasively identify patients in whom the veins are too distant from the site of late activation to deliver effective pacing. This method may prove useful in planning LV lead placement and thus may improve outcomes of CRT.
- © 2010 by American Heart Association, Inc.