Targeted Left Ventricular Lead Placement to Guide Cardiac Resynchronization Therapy - TARGET Study

Jun 02, 2014
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Author/Summarized by Author:
Anthony A. Bavry, MD, MPH, FACC
Summary Reviewer:
Deepak L. Bhatt, MD, MPH, MBA, FACC
Trial Sponsor:
NIHR UK, Papworth Hospital, Addenbrooke’s Charitable Trust
Date Presented:
01/01/2011
Date Updated:
06/02/2014
Original Posted Date:
06/02/2014
References

Description:

The goal of the trial was to evaluate cardiac resynchronization therapy (CRT) with targeted left ventricular (LV) lead placement compared with unguided lead placement.

Hypothesis:

Targeted LV lead placement will enhance CRT response.

Study Design

  • Randomized
  • Parallel

Patient Populations:

  • Patients in sinus rhythm with LV ejection fraction <35%, NYHA class III-IV, and QRS duration >120 ms

    Number of screened applicants: 247
    Number of enrollees: 220
    Duration of follow-up: 6 months
    Mean patient age: 72 years
    Percentage female: 23%
    Ejection fraction: 23%
    NYHA class: III-83%, IV-14%

Primary Endpoints:

  • Response rate defined as ≥15% reduction of LV end-systolic volume at 6 months

Secondary Endpoints:

  • ≥1 improvement in NYHA class
  • All-cause mortality
  • Composite of mortality and heart failure hospitalization

Drug/Procedures Used:

Patients undergoing CRT were randomized to targeted LV lead placement to the latest site of peak contraction with speckle tracking echocardiography (n = 110) versus unguided lead placement (n = 110).

Concomitant Medications:

At baseline in the targeted LV lead placement group, the use of angiotensin-converting enzyme inhibitors or angiotensin-receptor blockers was 95%, beta-blockers was 71%, and spironolactone was 57%.

Principal Findings:

Overall, 220 patients were randomized. In the targeted LV lead placement group, the mean age was 72 years, 23% were women, 83% had New York Heart Association (NYHA) class III symptoms, and mean LV ejection fraction was 23%.

In the targeted lead group, the LV lead was placed in the lateral wall in 46%, the posterior wall in 35%, and inferior wall in 12%. In the untargeted lead group, the LV lead was placed in the lateral wall in 47%, posterior wall in 38%, and inferior wall in 6% (p = 0.44).

LV ejection fraction response rate was 70% versus 55% (p = 0.031). Clinical response rate was 83% versus 65% (p = 0.003), respectively. The change in LV end-systolic volume at 6 months was -24% ± 14% in the targeted lead group versus 19% ± 16% in the untargeted group (p = 0.02).

All-cause mortality was similar between groups (p = 0.30); however, the composite outcome of death or heart failure hospitalization was reduced with targeted lead placement (p = 0.03).

Considering participants from both the TARGET randomized trial and registry (n = 200), optimal LV lead placement was associated with a significant change in LV systolic volume (-24%) compared with suboptimal LV lead placement (-12%; p < 0.001). Change in LV ejection fraction was 7% versus 4% (p = 0.02), respectively for optimal versus suboptimal LV lead placement. Last, optimal LV systolic lead placement was associated with improved survival (log-rank p = 0.003).

Interpretation:

Among patients undergoing CRT, targeted LV lead placement with speckle tracking echocardiography was feasible. Targeted lead placement resulted in enhanced CRT response. The secondary outcome of death or heart failure hospitalization was also reduced with targeted lead placement. Targeted lead placement was more likely to result in optimal lead placement, which was associated with improvement in LV systolic dimension, LV ejection fraction, and long-term survival. Larger studies examining the effect of this strategy on clinical outcomes are warranted.

References:

Kydd AC, Khan FZ, Watson WD, Pugh PJ, Virdee MS, Dutka DP. Prognostic Benefit of Optimum Left Ventricular Lead Position in Cardiac Resynchronization Therapy: Follow-Up of the TARGET Study Cohort (Targeted Left Ventricular Lead Placement to Guide Resynchronization Therapy). JACC Cardiovasc Heart Fail 2014;2:205-12.

Khan FZ, Virdee MS, Palmer CR, et al. Targeted Left Ventricular Lead Placement to Guide Cardiac Resynchronization Therapy. The TARGET Study: A Randomized, Controlled Trial. J Am Coll Cardiol 2012;59:1509-18.

Presented by Dr. Fakhar Khan at the ACC.11/i2 Summit, New Orleans, LA, April 5, 2011.

Keywords: Registries, Follow-Up Studies, Heart Failure, Heart Ventricles, Systole, Cardiac Resynchronization Therapy, Echocardiography


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