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

The Prognostic Role of Global Longitudinal Strain and NT-proBNP in Heart Failure Patients Receiving Cardiac Resynchronization Therapy

BACKGROUND

We aimed to evaluate whether baseline GLS (global longitudinal strain), NT-proBNP, and changes in these after cardiac resynchronization therapy (CRT) can predict long-term clinical outcomes and the echocardiographic-based response to CRT (defined by 15% relative reduction in left ventricular end-systolic volume).

METHODS

We enrolled 143 patients with stable ischemic heart failure (HF) undergoing CRT-D implantation. NT-proBNP and echocardiography were obtained before and 6 months after. The patients were followed up (median: 58 months) for HF-related deaths and/or HF hospitalizations (primary endpoint) or HF-related deaths (secondary endpoint).

RESULTS

A total of 84 patients achieved the primary and 53 the secondary endpoint, while 104 patients were considered CRT responders and 39 non-responders. At baseline, event-free patients had higher absolute GLS values (p < 0.001) and lower NT-proBNP serum levels (p < 0001) than those achieving the primary endpoint. A similar pattern was observed in favor of CRT responders vs. non-responders. On Cox regression analysis, baseline absolute GLS value (HR = 0.77; 95% CI, 0.51-1.91; p = 0.002) was beneficially associated with lower primary endpoint incidence, while baseline NT-proBNP levels (HR = 1.55; 95% CI, 1.43-2.01; p = 0.002) and diabetes presence (HR = 1.27; 95% CI, 1.12-1.98; p = 0.003) were related to higher primary endpoint incidence.

CONCLUSIONS

In HF patients undergoing CRT-D, baseline GLS and NT-proBNP concentrations may serve as prognostic factors, while they may predict the echocardiographic-based response to CRT.

Left bundle branch pacing on mechanical synchrony and myocardial work in bradycardia patients

Left bundle branch pacing (LBBP) has emerged as a novel physiological pacing method to produce narrower QRS duration, but whether it could restore mechanical synchrony and improve myocardial work still lacks sufficient evidence. Therefore, the goal of this study was to evaluate mechanical synchrony and myocardial work in LBBP. We collected 20 patients with LBBP due to symptomatic bradycardia and another 29 age-matched patients with right ventricular pacing (RVP). For LBBP patients, cardiac electro-mechanical synchrony and myocardial work were measured at baseline and 7 days after implantation and compared with the RVP patients. In the LBBP group, paced QRS duration and mechanical synchrony were not significantly different from baseline(all P > 0.05), but significantly smaller than that in the RVP group (all P<0.05). Meanwhile, global longitudinal strain (GLS) in LBBP was greater than that in the RVP group (17.7 ± 3.5% vs. 14.8 ± 3.1%, P < 0.05). Global myocardial work index and global constructive work were also better than that in the RVP group(all P<0.05). Global work efficiency was 91.9 ± 3.1%, which was greater when compared with RVP (P < 0.05). LBBP provides better cardiac electro-mechanical synchrony and more effective myocardial work than that in RVP, thus improving global heart function.

What Strain Analysis Adds to Diagnosis and Prognosis in Heart Failure Patients

Heart failure (HF) is a common disease that requires appropriate tools to correctly predict cardiovascular outcomes. Echocardiography represents the most commonly used method for assessing left ventricular ejection fraction and a cornerstone in the detection of HF, but it fails to procure an optimal level of inter-observer variability, leading to unsatisfactory prediction of cardiovascular outcomes. In this review, we discuss emerging clinical tools (global longitudinal strain of the left ventricle, the right ventricle, and the left atrium) that permitted an improvement in the diagnosis and ameliorated the risk stratification across different HF phenotypes. The review analyzes the speckle-tracking contributions to the field, discussing the limitations and advantages in clinical practice.

Longitudinal evaluation of diastolic dyssynchrony by SPECT gated myocardial perfusion imaging early after acute myocardial infarction and the relationship with left ventricular remodeling progression in a swine model

BACKGROUND

Left ventricular diastolic dyssynchrony (LVDD), a dyssynchronous relaxation pattern, has been known to develop after myocardial damage. We aimed to evaluate the dynamic changes in LVDD in the early stage of acute myocardial infarction (AMI) by phase analysis of 99mtechnetium methoxyisobutylisonitrile (99mTc-MIBI) single-photon emission computed tomography (SPECT) gated myocardial perfusion imaging (GMPI) and explore its relationship with the progression of left ventricular remodeling (LVR).

METHODS

The left anterior descending coronary arteries of 16 Bama miniature swine were occluded with a balloon to build AMI models. Animals were imaged by SPECT GMPI before AMI and at 1 day, 1 week and 4 weeks after AMI, and quantitative analysis was performed to determine the extent of left ventricle (LV) perfusion defects, left ventricular systolic dyssynchrony (LVSD) and the LVDD parameters: phase histogram bandwidth (PBW) and phase standard deviation (PSD). Echocardiography was simultaneously applied to evaluate left ventricular end-diastolic volume (LVEDV), left ventricular end-systolic volume (LVESV), left ventricular ejection fraction (LVEF), and the LVDD parameters: Te-12-diff and Te-12-SD. Myocardial injury markers were measured, and 12-lead ECGs were performed. The degree of LVR progression was defined as ΔLVESV (%) = (LVESVAMI4weeks - LVESVAMI1day)/LVESVAMI1day.

RESULTS

Thirteen swine completed the study. LVDD parameters changed dynamically at different time points after AMI. LVDD occurred as early as 1 day after AMI, peaked at 1 week, and trended toward a partial recovery at 4 weeks. Phase analysis on SPECT GMPI showed a significant correlation with tissue Doppler imaging for the assessment of LVDD during the longitudinal evaluation (r = 0.569 to 0.787, both P <0.05). During the univariate and multivariate regression analyses, the LVDD parameters PBW and PSD as of 1 day after AMI were significantly associated with the progression of LVR, respectively (PBW, β = 0.004, 95% CI 0.001 to 0.007, P = 0.024; PSD, β = 0.008, 95% CI 0.000 to 0.017, P = 0.049). Adjusted smooth curve fitting and threshold effect analysis indicated PBW and PSD break-point values of 142° and 60.4°, respectively, to predict the progression of LVR after AMI.

CONCLUSIONS

Phase analysis of SPECT GMPI can accurately and reliably characterize LVDD. LVDD occurred on the first day after AMI, reached its peak at 1 week, and partially recovered at 4 weeks after AMI. LVDD as evaluated by phase analysis of SPECT GMPI early after AMI was significantly associated with the progression of LVR. The early assessment of LVDD after AMI may provide helpful information for predicting the progression of LVR in the future.

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.

Peak strain dispersion within the left ventricle detected by two-dimensional speckle tracking in patients with uncomplicated systemic lupus erythematosus

Systemic lupus erythematosus (SLE) often leads to various cardiovascular diseases. We aimed to investigate the value of peak strain dispersion (PSD) in evaluating left ventricular dysfunction in patients with uncomplicated SLE. Eighty-seven female SLE patients and fifty-nine healthy female controls were recruited. The SLE patients were divided into inactive disease (SLE disease activity index (SLEDAI) ≤ 4; n = 48) and active disease (SLEDAI ≥ 5; n = 39) subgroups. Traditional echocardiography and two-dimensional speckle-tracking echocardiography were performed using a GE VividE9 ultrasound diagnostic system and an advanced quantitative analysis EchoPAC workstation (version 201), respectively. The global longitudinal strain (GLS) in the SLE with SLEDAI ≤ 4 group was comparable to that in the control group (- 19.89% vs - 20.7%; P = 0.061). However, GLS was obviously damaged in the SLE with SLEDAI ≥ 5 group compared with that in the control group (- 19.07% vs - 20.7%; P < 0.001). PSD impairment was observed in the SLE with SLEDAI ≤ 4 group (33.83 ms vs 31.44 ms; P = 0.012) and SLE with SLEDAI ≥ 5 groups (52.31 ms vs 31.44 ms; P < 0.001), but the largest difference was observed in the active disease group. Linear regression analysis showed that PSD was moderately correlated with the SLEDAI (r = 0.535; P < 0.001) in SLE patients with SLEDAI ≤ 4 and showed the best correlation with the SLEDAI (r = 0.646; P < 0.001) in the SLE patients with SLEDAI ≥ 5. A correlation between GLS and the SLEDAI (r = 0.359; P = 0.025) was found in the active disease group but not in the inactive disease group (r = 0.253; P = 0.082). PSD is more comprehensive and accurate for evaluating left ventricular subclinical dysfunction in SLE patients. In inactive SLE patients, PSD is a more sensitive index to evaluate early systolic dysfunction of the left ventricle. GLS may be a more vulnerable indicator of early left ventricular cardiac dysfunction in active SLE patients. Controlling disease activity may reduce the events of cardiac dysfunction.

Delay optimization of multipoint pacing increases the cardiac index and narrows the QRS width

INTRODUCTION

The benefits of MPP delay optimization on hemodynamics and ventricular contraction synchronicity can be quantified with cardiac index (CI) and QRS width. A delay with the maximum CI and minimum QRS width may be the optimized settings for multipoint pacing (MPP).

METHODS

Twelve patients with advanced heart failure who received cardiac resynchronization therapy defibrillation with MPP at the Third People's Hospital of Chengdu from March 2016 to April 2019 were included. Interventricular and intraventricular delays were optimized through noninvasive cardiac output monitoring and a 12 lead ECG.

RESULTS

According to CI, the optimized left ventricular- left ventricular - right ventricular delay setting was mainly 25 ms-25 ms and 40 ms-40 ms. And the delay with the minimum QRS width was mainly in 5 ms-5 ms, 25 ms-25 ms, and 40 ms-25 ms. The optimal MPP configuration increased CI compared to the MPP setting that produced the minimum CI (4.5 ± 1.3 vs. 2.8 ± 1.0 L/min/m2, P < 0.001). The QRS width of the optimized MPP was narrower than the MPP setting that produced the maximum QRS width (127 ± 20 vs. 160 ± 29 ms, P < 0.001).

CONCLUSION

Delay optimization improves hemodynamic response and ventricular contraction synchronicity. The delay of 25 ms-25 ms may be the optimal setting for most MPP patients.