Evaluation of global longitudinal strain of left ventricle and regional longitudinal strain in the region of left ventricular leads predicts the response to cardiac resynchronization therapy in patients with ischemic heart failure

Association of QRS narrowing with response to cardiac resynchronization therapy-a systematic review and meta-analysis of observational studies

Prolonged QRS duration, which reflects a higher degree of mechanical dysynchrony, is a predictor of response to CRT. However, the association of QRS narrowing after biventricular pacing with CRT response rates is not clear. Our aim was to conduct a systematic review and meta-analysis on the association between QRS narrowing after cardiac resynchronization therapy (CRT) and clinical and echocardiographic response to CRT in patients with heart failure. Two independent investigators searched MedLine and EMBASE databases through July 2018 without any limitations. Studies providing estimates (continuous data) on the association of QRS shortening with either clinical (defined as New York Heart Association (NYHA) reduction ≥ 1) or echocardiographic (defined as left ventricular end-systolic volume (LVESV) reduction ≥ 15%) response to CRT were finally included in the quantitative synthesis. We included 32 studies (14 studies (1274 patients mean age 64 years old, males 79.3%) using clinical CRT response and 18 studies (1270 patients, mean age 64 years old, males 69.1%) using echocardiographic CRT response). A significant association between QRS narrowing and shorter attained QRS duration with clinical and echocardiographic CRT response was observed. The observed association was independent of the timing of QRS width measurement after CRT implantation. Acute and late improvement of electrical dysynchrony as depicted by QRS narrowing following biventricular pacing is associated with clinical and echocardiographic response to CRT. However, large prospective studies are needed to further examine our findings.

Global longitudinal strain predicts responders after cardiac resynchronization therapy-a systematic review and meta-analysis

To evaluate the association between baseline global longitudinal strain (GLS) and ΔGLS (difference of baseline GLS and follow-up) and cardiac resynchronization therapy (CRT) response defined either with clinical or with echocardiographic characteristics. This meta-analysis was performed in accordance to both the Meta-Analysis of Observational Studies in Epidemiology and Strengthening the Reporting of Observational Studies in Epidemiology guidelines. Two independent investigators performed a comprehensive systematic search in MedLine, EMBASE and Cochrane databases through September 2019 without limitations. Data analysis was performed by using the Review Manager software (RevMan), version 5.3, and Stata 13 software. A p value of less than 0.05 (two-tailed) was considered statistically significant. Twelve studies (1004 patients, mean age 63.8 years old, males 69.4%) provided data on the association of baseline GLS with the response to CRT therapy. We found that CRT responders had significantly better resting GLS values compared with non-responders [GLS mean difference -2.13 (-3.03, -1.23), p < 0.001, I² 78%]. Furthermore, CRT responders had significantly greater improvement of GLS at follow-up compared with non-responders [ΔGLS mean difference -3.20 (-4.95, -1.45), p < 0.001, I² 66%]. These associations remained significant in a subgroup analysis including only studies with similar CRT response definition. In this meta-analysis, we found that CRT responders had a baseline and ΔGLS significantly higher than the non-responders strengthening the central role of GLS as a tool for selecting candidates for CRT. Furthermore, improved GLS values after CRT may be used to better define CRT responders.

Left ventricular global longitudinal strain in predicting CRT response: one more J-shaped curve in medicine

The aim of the study was: (1) to verify the hypothesis that left ventricular global longitudinal strain (LVGLS) may be of additive prognostic value in prediction CRT response and (2) to obtain such a LVGLS value that in the best optimal way enables to characterize potential CRT responders. Forty-nine HF patients (age 66.5 ± 10 years, LVEF 24.9 ± 6.4%, LBBB 71.4%, 57.1% ischemic aetiology of HF) underwent CRT implantation. Transthoracic echocardiography was performed prior to and 15 ± 7 months after CRT implantation. Speckle-tracking echocardiography was performed to assess longitudinal left ventricular function as LVGLS. The response to CRT was defined as a ≥ 15% reduction in the left ventricular end-systolic volume (∆LVESV). Thirty-six (73.5%) patients responded to CRT. There was no linear correlation between baseline LVGLS and ∆LVESV (r = 0.09; p = 0.56). The patients were divided according to the percentile of baseline LVGLS: above 80th percentile; between 80 and 40th percentile; below 40th percentile. Two peripheral groups (above 80th and below 40th percentile) formed “peripheral LVGLS” and the middle group was called “mid-range LVGLS”. The absolute LVGLS cutoff values were − 6.07% (40th percentile) and − 8.67% (80th percentile). For the group of 20 (40.8%) “mid-range LVGLS” patients mean ΔLVESV was 33.3 ± 16.9% while for “peripheral LVGLS” ΔLVESV was 16.2 ± 18.8% (p < 0.001). Among non-ischemic HF etiology, all “mid-range LVGLS” patients (100%) responded positively to CRT (in “peripheral LVGLS”—55% responders; p = 0.015). Baseline LVGLS may have a potential prognostic value in prediction CRT response with relationship of inverted J-shaped pattern. “Mid-range LVGLS” values should help to select CRT responders, especially in non-ischemic HF etiology patients.

Left ventricular global longitudinal strain and mechanical dispersion predict response to multipoint pacing for cardiac resynchronization therapy

PURPOSE

To evaluate the acute effect of multipoint pacing (MPP) and search for the better baseline predictors of response to MPP for guiding patient selection.

METHODS

We enrolled 46 heart failure patients scheduled for implantation of MPP-enabled cardiac resynchronization therapy (CRT) devices. An acute pacing protocol including conventional CRT and MPP pacing configurations was performed after implantation. Echocardiography was used at baseline and during pacing test, and response was defined as left ventricular (LV) end-systolic volume (ESV) reduction ≥ 15% at 6-month follow-up.

RESULTS

MPP response was present in 32 (69%) patients. Responders showed significantly superior LV ejection fraction, global longitudinal peak strain (GLPS), and mechanical dispersion (MD) with MPP than with conventional CRT (all P < 0.05). Baseline GLPS (OR 1.524; 95% CI 1.031-2.251; P = 0.034) and MD (OR 1.048; 95% CI 1.016-1.081; P = 0.003) were independent predictors of MPP response in multivariate regression analysis. Both |GLPS| and MD were significantly correlated with percentage change in LVESV (▵LVESV%) at 6-month follow-up (r = 0.731 and r = 0.696, respectively; all P < 0.001). |GLPS| ≥ 5.0% combined with MD ≥ 120 ms predicted MPP response with the optimal sensitivity of 91% and specificity of 71% (AUC = 0.848, P < 0.001).

CONCLUSIONS

MPP tends to be superior to conventional CRT in improving acute response. |GLPS| and MD can successfully predict response to MPP, and their combination can further improve the prediction accuracy of response.

Mechanical dyssynchrony and deformation imaging in patients with functional mitral regurgitation

Chronic functional mitral regurgitation (FMR) is a frequent finding of ischemic heart disease and dilated cardiomyopathy (DCM), associated with unfavourable prognosis. Several pathophysiologic mechanisms are involved in FMR, such as annular dilatation and dysfunction, left ventricle (LV) remodeling, dysfunction and dyssynchrony, papillary muscles displacement and dyssynchrony. The best therapeutic choice for FMR is still debated. When optimal medical treatment has already been set, a further option for cardiac resynchronization therapy (CRT) and/or surgical correction should be considered. CRT is able to contrast most of the pathophysiologic determinants of FMR by minimizing LV dyssynchrony through different mechanisms: Increasing closing forces, reducing tethering forces, reshaping annular geometry and function, correcting diastolic MR. Deformation imaging in terms of two-dimensional speckle tracking has been validated for LV dyssynchrony assessment. Radial speckle tracking and three-dimensional strain analysis appear to be the best methods to quantify intraventricular delay and to predict CRT-responders. Speckle-tracking echocardiography in patients with mitral valve regurgitation has been usually proposed for the assessment of LV and left atrial function. However it has also revealed a fundamental role of intraventricular dyssynchrony in determining FMR especially in DCM, rather than in ischemic cardiomyopathy in which MR severity seems to be more related to mitral valve deformation indexes. Furthermore speckle tracking allows the assessment of papillary muscle dyssynchrony. Therefore this technique can help to identify optimal candidates to CRT that will probably demonstrate a reduction in FMR degree and thus will experience a better outcome.