Usefulness of Echocardiographically Guided Left Ventricular Lead Placement for Cardiac Resynchronization Therapy in Patients With Intermediate QRS Width and Non-Left Bundle Branch Block Morphology

Abstract

The current guidelines most strongly support cardiac resynchronization therapy (CRT) for patients with heart failure with a QRS width of 150 ms and left bundle branch block (LBBB). Our objective was to assess the potential benefit of echocardiographically guided left ventricular (LV) lead positioning for patients with a QRS width = 120 ms, and ejection fraction of <= 35% to LV lead guided to the site of latest mechanical activation by speckle tracking radial strain versus routine implantation.

The predefined primary end point was heart failure hospitalization or death within 2 years. This substudy included 151 CRT patients with matching echocardiographic and LV lead position data and complete follow-up data.

Patients with a QRS width of 120 to 149 ms or non-LBBB and LV lead concordant or adjacent to the site of latest mechanical activation had favorable outcomes after CRT similar to those with LBBB or a QRS width of 150 ms. In contrast, patients with a QRS of 120 to 149 ms or non-LBBB and remote LV leads had unfavorable outcomes (hazard ratio 5.45, 95% confidence interval 2.36 to 12.6, p<0.001, and hazard ratio 4.92, 95% confidence interval 2.12 to 11.39, p<0.001, respectively, with significant interaction after adjusting for baseline variables, p = 0.038 and p = 0.008).

In conclusion, LV lead positioning with respect to the echocardiographic site of latest activation was significantly associated with more favorable clinical outcomes in patients with a QRS duration <150 ms and/or non-LBBB. Additional prospective study is warranted. (C) 2014 Elsevier Inc.

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