Clinical Trials

In this study we propose to evaluate the utility of radial strain imaging using speckle tracking to predict the response to CRT in patients with ischemic cardiomyopathy (ICMP) with NYHA functional class 2-4 heart failure and a standard guideline-based CRT indication, and to determine the value of lead localization determined by radial strain imaging in a prospective, randomized manner. We will compare two randomized groups of CRT recipients implanted with CRT-D systems. In the control group, implantation will be performed in the usual manner and the lead will be placed at the discretion of the implanting physician, preferably at posterolateral LV sites . In the study group, leads will be placed in areas of latest contraction that lack significant scar, as determined by speckle tracking imaging. The primary outcome measure for comparison between the 2 groups will be echocardiographic response (as assessed by percent reduction in left ventricular end systolic volumes) at 6 months post-implantation. In addition, clinical response parameters will also be measured as secondary end points. We hypothesize that 1) patients showing greater dyssynchrony and/or discoordination index with speckle tracking will derive a significantly greater response to cardiac resynchronization therapy; and 2) patients allocated to the image-guided LV lead placement group will derive a significantly greater response to CRT than patients in the non- guided implantation (control) group. If radial strain imaging proves useful for improving the CRT response rate and identification of patients likely to respond, it will have important clinical and economic implications by improving individual outcomes and more effective utilization of constrained health care resources. Furthermore, if echo-guided lead implantation proves to be effective in reducing the relatively large non-response rate to cardiac resynchronization therapy, it will likely result in increased device utilization among eligible heart failure patients. Specific Aims Aim #1: To show that in patients with ischemic cardiomyopathy, implantation of a CRT LV lead guided by radial strain imaging results in a significantly greater echocardiographic and clinical response to cardiac resynchronization therapy compared with conventional implantation techniques. Aim #2: To show that speckle tracking strain data can be used to identify the degree of echocardiographic response to CRT, using both dyssynchrony (time to peak strain ) and discoordination indices .