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.

Cardiac resynchronization therapy guided by multimodality cardiac imaging.

AIMS: Up to 30-45% of implanted patients are non-responders to CRT. We evaluated the role of a 'CRT team' using cardiac magnetic resonance (CMR) and longitudinal myocardial strain to identify the target area defined as the most delayed and viable region for LV pacing. METHODS AND RESULTS: A total of 100 heart failure patients candidates for CRT divided into two groups were enrolled. Group 1 consisted of 50 consecutive patients scheduled for CRT and prospectively included. Group 2 (control) consisted of 50 patients with a CRT device implanted according to standard clinical practice and matched for age, sex, and LVEF with group 1. Patients were evaluated at baseline and at 6-month follow-up. In group 1, patients underwent two-dimensional speckle-tracking assessment of longitudinal myocardial strain and CMR imaging to identify the target area for LV lead pacing. A positive response to CRT was defined as a reduction of ≥15% of the LV end-systolic volume at 6-month follow-up. A total of 39 (78%) patients of group 1 were classified as responders to CRT whilst in group 2, only 28 (56%) were responders (P = 0.019). The 'CRT team' identified as target for LV pacing the lateral area in 30 (60%) patients, and the anterolateral or posterolateral areas in 12 (24%) patients. In 8 (16%) patients, the target was far from the lateral area, in the anterior or posterior areas. The patients with concordant position exhibited the highest positive response (93.1%) to CRT. CONCLUSIONS: Multimodality cardiac imaging as a guide for CRT implantation is useful to increase response rate.