Left Ventricular Lead Position Guided by Parametric Strain Echocardiography Improves Response to Cardiac Resynchronization Therapy

Background: There is still a significant proportion of patients with heart failure who fail to improve after cardiac resynchronization therapy (CRT). The investigators used parametric two-dimensional speckle-tracking echocardiography with polar plots of the amplitude and timing of left ventricular (LV) longitudinal strain to guide implantation of the LV lead, with the aim of increasing CRT response. Methods: Sixty-four patients who underwent LV lead implantation guided by two-dimensional speckle-tracking echocardiography (study group) and 64 patients treated with standard CRT implantation (control group) were retrospectively analyzed in this study. A positive response to CRT was defined as a reduction of ≥15% in LV end-systolic volume 6 months after implantation. Parametric two-dimensional speckle-tracking echocardiographic evaluation was associated with myocardial end-diastolic wall thickness assessment for recognition of nonviable or irreversibly damaged myocardial tissue. Results: Compared with the control group, the number of responders increased in the study group (75% vs 48%, P = .002) and in the subgroups of nonischemic (85% vs 59%, P = .022) and ischemic (65% vs 38%, P = .032) patients. The magnitude of echocardiographic LV response also increased in the overall study group and subgroups. In the ischemic patients, the size of transmural scar area correlated with LV reverse remodeling (r = 0.693, P < .001). Conclusions: Echocardiography-guided LV lead implantation on the basis of parametric polar plots of LV longitudinal myocardial strain increases both the number of responders and the magnitude of echocardiographic response to CRT. In ischemic patients, size of transmural scar tissue negatively affects CRT response, even when LV lead position is optimized.