Multimodality-Guided LV Lead Placement in CRT

Nov 03, 2020
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Authors:
Borgquist R, Carlsson M, Markstad H, et al.
Citation:
Cardiac Resynchronization Therapy Guided by Echocardiography, MRI, and CT Imaging: A Randomized Controlled Study. JACC Clin Electrophysiol 2020;6:1300-1309.
Summary By:
Thomas C. Crawford, MD, FACC

Quick Takes

  • There was no difference in clinical or echocardiographic outcomes in this randomized study of echocardiographically selected LV segment in CRT implantation.
  • Cardiac MRI allows us to identify scar in ischemic cardiomyopathy patients, which may inform suboptimal location of an LV lead.
  • In patients with nonischemic cardiomyopathy, the benefit of MRI was helpful in identifying underlying causes of the cardiomyopathy.

Study Questions:

Does selecting the left ventricular (LV) target segment by echocardiography-derived late mechanical activation help to increase responder rates to cardiac resynchronization therapy (CRT)?

Methods:

This was a prospective, blinded, controlled trial randomizing patients with class I indications for CRT to: 1) LV lead placement at the latest mechanically activated available segment (free of transmural scar), determined by radial strain echocardiography, cardiac computed tomography (CT), and cardiac magnetic resonance (MRI); or 2) routine LV lead placement. The primary endpoint was reduction of LV end-systolic volume by ≥15% at 6 months post-implantation.

Results:

There were 102 patients (27% women, 46% with ischemic cardiomyopathy, 63% in New York Heart Association [NYHA] functional class III, 74% with left bundle branch block, and with mean ejection fraction of 23%). Patients were followed for an average of 47 months. Based on imaging, optimal or adjacent lead placement seemed feasible in 96% of cases; however, it was ultimately obtained only in 83% of the intervention group versus 80% of the control group. There was no difference in the percent of the patients who showed LV end-systolic volume response and improved 1 NYHA functional class. Death or heart failure hospitalization within 2 years occurred in 6% (2% of the intervention group vs. 10% of the control group; p = 0.07).

Conclusions:

Radial strain-guided LV lead placement, in combination with CT and MRI, did not result in increased clinical response or echocardiographic improvement.

Perspective:

The study failed to demonstrate benefit to an a priori evaluation of the delayed activation on echo coupled with anatomic information from CT (coronary sinus tributary anatomy) and MRI (large scar preventing lead placement). Ultimately, success of CRT seems to depend on the ability to place the LV lead in the empirically desired location. Preprocedure imaging does not change that basic limitation of the implant procedure.

Clinical Topics: Arrhythmias and Clinical EP, Cardiovascular Care Team, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Acute Heart Failure, Computed Tomography, Echocardiography/Ultrasound, Magnetic Resonance Imaging, Nuclear Imaging

Keywords: Arrhythmias, Cardiac, Bundle-Branch Block, Cardiac Resynchronization Therapy, Cardiomyopathies, Diagnostic Imaging, Echocardiography, Heart Failure, Magnetic Resonance Imaging, Myocardial Ischemia, Tomography, X-Ray Computed


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