Mechanical dyssynchrony: How do we measure it, what it means, and what we can do about it

Prognostic significance of phase analysis using SPECT myocardial perfusion imaging in heart failure: a systematic review and meta-analysis

Left ventricular mechanical dyssynchrony (LVMD) is an important prognostic factor for heart failure (HF). Phase analysis of myocardial perfusion SPECT is actively being researched to evaluate LVMD. We performed a systematic review and meta-analysis on the prognostic significance of LVMD using gated SPECT in HF patient. PubMed, Embase, and the Cochrane library were searched until January 10, 2024, for studies reporting the prognostic value of LVMD in HF patients using gated SPECT for outcomes of all-cause death, cardiac death, or major adverse cardiovascular event (MACE). Hazard ratios (HRs) along with their corresponding 95% confidence intervals (CIs) were combined through meta-analysis employing a random-effects model. Funnel plots and Egger's tests were utilized to evaluate publication bias, and trim-and-fill method were applied where bias was identified. Ten studies (2585 patients) were included; six on MACE and five on all-cause or cardiac death. Prognoses were worse in patients with LVMD assessed by SPECT than in those without LVMD, with the overall pooled HR for MACE being 2.05 (95% CI, 1.65-2.54). The pooled HR for all-cause or cardiac death was 2.08 (95% CI, 1.10-3.94); however, publication bias was present (p = 0.0024), and after adjustment, the prognostic value of LVMD was not statistically significant (HR, 1.24; 95% CI, 0.68-2.23). Assessing LVMD through myocardial perfusion SPECT proves to be a significant indicator of subsequent adverse cardiac events in HF patients. Utilizing phase analysis of SPECT could offer valuable insights for risk assessment and decision-making regarding therapy in HF patients.

Assessing subaortic right ventricle function after atrial switch repair through myocardial work analysis

Background

The Mustard and Senning operations for dextro-transposition of the great arteries (D-TGA) establish a biventricular physiology with a subaortic right ventricle (sRV). While prolonged QRS has been associated with worse prognosis in these patients, current echocardiographic tools fall short in adequately assessing the (mal)performance and function decline of the sRV during follow-up. The present study is the first to characterize Myocardial Work (MW) indices of the sRV in D-TGA patients after Mustard/Senning repair.

Methods and results

All adult D-TGA patients at follow-up in the University Hospital of Leuven between 2018 and 2022 were screened for inclusion. We retrospectively collected the most recent electrocardiogram parameters, 2D echocardiographic images and serum biomarkers' values. Offline calculations of MW indices were performed. We established correlations between all variables and categorized patients into QRS<120 ms and QRS≥120 ms for further analysis. A total of 51 D-TGA patients were included (13 Mustard, 33 male, 39 ± 6 years). QRS duration increased with age and was correlated with sRV dimensions and serum levels of troponins (R = 0.42, p < 0.01) and NT-proBNP (R = 0.31, p = 0.03). However, no significant correlation was found between QRS duration and intraventricular desynchrony or conventional functional echocardiographic parameters. QRS prolongation was associated with a deterioration in septal, but not lateral, MW parameters. Patients with QRS≥120 ms had significantly larger ventricles and higher levels of troponins and NT-proBNP.

Conclusion

QRS prolongation after Mustard/Senning repair is linked to ventricular dilatation and worse performance, particularly affecting the septal wall. Global and regional MW analysis may be useful to assess the subclinical deterioration of sRV function.

Prognostic value of mechanical dyssynchrony in patients with heart failure: a systematic review

BACKGROUND

Heart failure (HF) significantly impacts quality of life and healthcare systems worldwide. Assessing left ventricular mechanical dyssynchrony (LVMD) is crucial for understanding cardiac function and optimizing treatments like cardiac resynchronization therapy (CRT). Phase analysis using gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) has shown promise in predicting outcomes, yet recent comprehensive reviews are lacking.

OBJECTIVE

To systematically assess the prognostic value of phase analysis by gated SPECT MPI in the HF population through a systematic review.

METHODS

We conducted a systematic review by collecting studies from databases including PubMed, CINAHL, and Web of Science. Two reviewers independently performed study selection, data extraction, and risk of bias assessment. Systematic reviews were conducted using Review Manager Software 5.4 and STATA 16.0.

RESULTS

A total of 2004 patients from seven studies were included in our review and analysis. The systematic review indicated that patients with predetermined clinical events had higher PSD [MD = 6.45, 95% CI (5.83, 7.07), p < 0.00001] and PBW [MD = 7.91, 95% CI (5.64, 10.19), p < 0.00001]. The diagnosis of LVMD determined by PSD [HR = 1.05, 95% CI (1.01, 1.08), p = 0.007] was a strong predictor of endpoint events compared to PBW [HR = 1.95, 95% CI (0.48, 7.89), p = 0.35].

CONCLUSIONS

The analysis demonstrated that phase information obtained from gated SPECT MPI is of significant prognostic value in patients with heart dysfunction. It effectively enhances clinical risk models, providing reliable guidance for patient treatment.

Speckle Tracking Echocardiography in Patients with Non-Ischemic Dilated Cardiomyopathy Who Undergo Cardiac Resynchronization Therapy: A Narrative Review

Non-ischemic dilated cardiomyopathy (DCM) represents a significant cause of heart failure, defined as the presence of left ventricular (LV) dilatation and systolic dysfunction unexplained solely by abnormal loading conditions or coronary artery disease. Cardiac resynchronization therapy (CRT) has emerged as a cornerstone in the management of heart failure, particularly in patients with DCM. However, identifying patients who will benefit the most from CRT remains challenging. Speckle tracking echocardiography (STE) has garnered attention as a non-invasive imaging modality that allows for the quantitative assessment of myocardial mechanics, offering insights into LV function beyond traditional echocardiographic parameters. This comprehensive review explores the role of STE in guiding patient selection and optimizing outcomes in CRT for DCM. By assessing parameters such as LV strain, strain rate, and dyssynchrony, STE enables a more precise evaluation of myocardial function and mechanical dyssynchrony, aiding in the identification of patients who are most likely to benefit from CRT. Furthermore, STE provides valuable prognostic information and facilitates post-CRT optimization by guiding lead placement and assessing response to therapy. Through an integration of STE with CRT, clinicians can enhance patient selection, improve procedural success rates, and ultimately, optimize clinical outcomes in patients with DCM. This review underscores the pivotal role of STE in advancing personalized management strategies for DCM patients undergoing CRT.

MR Uniformity Ratio Estimates to Evaluate Ventricular Mechanical Dyssynchrony and Prognosis After ST-Segment Elevation Myocardial Infarction

BACKGROUND

The impact of left ventricular mechanical dyssynchrony (LVMD) on the long-term prognosis of ST-segment elevation myocardial infarction (STEMI) is unclear.

HYPOTHESIS

MR uniformity ratio estimates (URE) can detect LVMD and assess STEMI prognosis.

STUDY TYPE

Retrospective analysis of a prospective multicenter registry (EARLY-MYO trial, NCT03768453).

POPULATION

Overall, 450 patients (50 females) with first-time STEMI were analyzed, as well as 40 participants without cardiovascular disease as controls.

FIELD STRENGTH/SEQUENCE

3.0-T, balanced steady-state free precession cine and late gadolinium enhancement imaging.

ASSESSMENT

MRI data were acquired within 1 week of symptom onset. Major adverse cardiovascular events (MACEs), including cardiovascular death, nonfatal re-infarction, hospitalization for heart failure, and stroke, were the primary clinical outcomes. LVMD was represented by circumferential URE (CURE) and radial URE (RURE) calculated using strain measurements. The patients were grouped according to clinical outcomes or URE values. Patients' clinical characteristics and MR indicators were compared.

STATISTICAL TESTS

The Student's t-test, Mann-Whitney U test, chi-square test, Fisher's exact test, receiver operating characteristic curve analysis with area under the curve, Kaplan-Meier analysis, Cox regression, logistic regression, intraclass correlation coefficient, c-index, and integrated discrimination improvement were used. P < 0.05 was considered statistically significant.

RESULTS

CURE and RURE were significantly lower in patients with STEMI than in controls. The median follow-up was 60.5 months. Patients with both lower CURE and RURE values experienced a significantly higher incidence of MACEs by 3.525-fold. Both CURE and RURE were independent risk factors for MACEs. The addition of UREs improved diagnostic efficacy and risk stratification based on infarct size and left ventricular ejection fraction (LVEF). The indicators associated with LVMD included male sex, serum biomarkers (peak creatine phosphokinase and cardiac troponin I), infarct size, and LVEF.

DATA CONCLUSION

CURE and RURE may be useful to evaluate long-term prognosis after STEMI.

EVIDENCE LEVEL

4 TECHNICAL EFFICACY: Stage 2.

Predictors and outcomes of cardiac dyssynchrony among patients with heart failure attending Benjamin Mkapa Hospital in Dodoma, central Tanzania: A protocol of prospective-longitudinal study

INTRODUCTION

Cardiac Dyssynchrony is prevalent among patients with heart failure with high cost of care and potentially poor outcomes. Nevertheless, little is known about cardiac dyssynchrony among heart failure patients, especially in developing countries. This study aims at assessing the predictors and outcomes of cardiac dyssynchrony among heart failure patients attending the cardiology department at Benjamin Mkapa Referral Hospital in Dodoma, central Tanzania.

METHODS

The study will follow a prospective longitudinal design involving participants aged 18 years and above with heart failure attending the Cardiology Department at Benjamin Mkapa Hospital. Heart failure will be identified based on Framingham's score and patients will be enrolled and followed up for six months. Baseline socio-demographic and clinical characteristics will be taken during enrollment. Outcomes of interest at six months include worsening of heart failure, readmission and death. Continuous data will be summarized as Mean (SD) or Median (IQR), and categorical data will be summarized using proportions and frequencies. Binary logistic regression will be used to determine predictors and outcomes of Cardiac Dyssynchrony among patients with heart failure.

Left ventricular systolic dyssynchrony: a novel imaging marker for early assessment of myocardial damage in Chinese type 2 diabetes mellitus patients with normal left ventricular ejection fraction and normal myocardial perfusion

OBJECTIVES

Myocardial damage is the important cause of heart failure (HF) in type 2 diabetes mellitus (T2DM), which is difficult to early diagnose, especially in T2DM with normal left ventricular ejection fraction (LVEF) and normal myocardial perfusion. The goal was to evaluate myocardial damage in T2DM with normal LVEF and normal myocardial perfusion by detecting left ventricular systolic dyssynchrony (LVSD), and find out the risk factors associated with LVSD.

METHODS

This study included 95 T2DM with normal LVEF, normal myocardial perfusion. 69 consecutive individuals without T2DM and CAD were enrolled as the control group with age-, sex- and BMI-matched. All participants underwent stress/rest 99mtechnetium-sestamibi (99mTc-MIBI) gated myocardial perfusion imaging (GMPI) and two-dimensional echocardiography within 1 week. Clinical data including age, gender, BMI, duration of diabetes, chronic diabetic complications, glycated haemoglobin A1c (HbA1c), fast blood glucose (FBG) and Brain Natriuretic Peptide (BNP) were collected from medical records. Left ventricular synchrony parameters were acquired, including phase standard deviation (PSD) and phase histogram bandwidth (PBW) by rest GMPI.

RESULTS

PSD and PBW in T2DM group were significantly higher than control group (P < .05). LVSD was detected in 20 (21%) T2DM patients. Compared to non-LVSD T2DM group, LVSD T2DM group had higher BMI, higher prevalence of BNP [Formula: see text] 35 pg/mL and chronic diabetic complications (P < .05). BNP [Formula: see text] 35 pg/mL had mild positive association with LVSD (r = 0.318, P = .004). In multivariate logistic regression, chronic diabetic complications and high BMI (> 23.4 kg/m2) were independent risk factors of LVSD (OR 5.64, 95% CI 1.58-20.16, P = .008; OR 6.77, 95% CI 1.59-28.89, P = .010).

CONCLUSIONS

LVSD existed in T2DM patients with normal LVEF and normal myocardial perfusion. Chronic diabetic complications and high BMI (> 23.4 kg/m2) were the independent risk factors of LVSD. LVSD based on GMPI can be the novel imaging marker to early assess myocardial damage in T2DM patients.

The Value of Stress-Gated Blood Pool SPECT in Predicting Early Postoperative Period Complications in Ischemic Cardiomyopathy Patients: Focus on Mechanical Dyssynchrony

(1) Objective: The objective of this study was to assess the prognostic value of stress-gated blood pool SPECT (GBPS) estimates in patients with ischemic cardiomyopathy (ICM) in the early postoperative period. (2) Methods: A total of 57 patients (age 59.7 ± 6.6, 47 men) with ICM and LV ejection fraction (30 [27.5; 35]%) were enrolled in the study. Before surgical treatment, all patients underwent GBPS (rest-stress, dobutamine doses of 5/10/15 µg/kg/min). Stress-induced changes in left ventricular (LV) ejection fraction, peak ejection rate, volumes, and mechanical dyssynchrony (phase histogram standard deviation, phase entropy (PE), and phase histogram bandwidth) were estimated. Two-dimensional transthoracic echocardiography was performed baseline. Serum levels of NT-proBNP were analyzed with enzyme-linked immunoassay. (3) Results: After surgical treatment, patients were divided into two groups, one, with death, the need for an intra-aortic balloon pump (IABP) or/and inotropic support with a stay in the intensive care unit for more than two days and two, without complications in the early postoperative period (EPOP). Complicated EPOP (CEPOP) was observed in 17 (30%) patients (death-2, IABP-4, extra inotropic support in intensive care unit-11), and 40 patients had no complications (NCEPOP). GBPS showed differences in LV EDV (mL) (321 [268; 358] vs. 268 [242; 313], p = 0.02), LV ESV (mL) (242 [201; 282] vs. 196 [170; 230], p = 0.005), and stress-induced changes in PE (1 (-2; 3) vs. -2 (-4; 0), p = 0.02). Aortic cross-clamp time and stress-induced changes in PE between rest and dobutamine dose of 10 µg/kg/min were the only independent predictors of CEPOP. An increase in LV entropy ≥ 1 on the dobutamine dose of 10µg/kg/min in comparison to rest investigation showed AUC = 0.853 (sensitivity = 62%, specificity = 90%, PPV = 71%; NPV = 85%; p < 0.0001). Conclusion: Stress-induced changes in PE obtained during low-dose dobutamine GBPS are associated with a complicated course of the early postoperative period after surgical treatment for ICM.

Relationship between intraventricular mechanical dyssynchrony and left ventricular systolic and diastolic performance: An in vivo experimental study

Left ventricular mechanical dyssynchrony (LVMD) refers to the nonuniformity in mechanical contraction and relaxation timing in different ventricular segments. We aimed to determine the relationship between LVMD and LV performance, as assessed by ventriculo-arterial coupling (VAC), LV mechanical efficiency (LVeff ), left ventricular ejection fraction (LVEF), and diastolic function during sequential experimental changes in loading and contractile conditions. Thirteen Yorkshire pigs submitted to three consecutive stages with two opposite interventions each: changes in afterload (phenylephrine/nitroprusside), preload (bleeding/reinfusion and fluid bolus), and contractility (esmolol/dobutamine). LV pressure-volume data were obtained with a conductance catheter. Segmental mechanical dyssynchrony was assessed by global, systolic, and diastolic dyssynchrony (DYS) and internal flow fraction (IFF). Late systolic LVMD was related to an impaired VAC, LVeff , and LVEF, whereas diastolic LVMD was associated with delayed LV relaxation (logistic tau), decreased LV peak filling rate, and increased atrial contribution to LV filling. The hemodynamic factors related to LVMD were contractility, afterload, and heart rate. However, the relationship between these factors differed throughout the cardiac cycle. LVMD plays a significant role in LV systolic and diastolic performance and is associated with hemodynamic factors and intraventricular conduction.

Prognostic value of ventricular mechanical dyssynchrony in patients with left ventricular aneurysm: A comparative study of medical and surgical treatment

BACKGROUND

The prognostic value of left ventricular (LV) mechanical dyssynchrony (MD) in patients with LV aneurysm (LVA) is unclear. This study aimed to investigate the long-term prognostic value of LVMD in LVA patients.

METHODS

92 consecutive patients who underwent 99mTc-sestamibi-gated SPECT myocardial perfusion imaging (GSPECT) were retrospectively analyzed and followed-up for a median of 63 months (range, 1-73 months). LV function and histogram bandwidth (BW) were analyzed by QGS software. LVMD was defined by ROC analysis. Cardiac death was defined as the primary endpoint, and the composite of cardiac deaths and severe or acute heart failure (MACE) as the secondary endpoint.

RESULTS

The annual cardiac mortality rate of LVA patients with LVMD and treated by surgical therapy was significantly lower than those treated by medical therapy (2.40% vs. 6.40%, P < .05) but not annual MACE rate (6.61% vs. 10.06%, P > .05). In patients without LVMD, no significant difference in survival and MACE-free survival between medical and surgical treatment. In addition, the occurrence of LVMD is related to the worsen cardiac outcome in terms of MACE and cardiac death, independent of the treatment methods. BW was an independent predictor for MACE (HR 1.010, P < .01) and LVEF (HR .928, P < .05) was an independent predictor for cardiac death in all LVA patients.

CONCLUSIONS

LVA patients with LVMD might be associated with high risk for cardiac death and surgical treatment might improve cardiac survival compared to medical therapy in these patients.

A Left Ventricular Mechanical Dyssynchrony-Based Nomogram for Predicting Major Adverse Cardiac Events Risk in Patients With Ischemia and No Obstructive Coronary Artery Disease

Background

The risk stratification of patients with ischemia and no obstructive coronary artery disease (INOCA) remains suboptimal. This study aims to establish a left ventricular mechanical dyssynchrony (LVMD)-based nomogram to improve the present situation.

Methods

Patients with suspected coronary artery disease (CAD) were retrospectively enrolled and divided into three groups: normal (stenosis &lt;50%, without myocardial ischemia), INOCA (stenosis &lt;50%, summed stress score &gt;4, summed difference score ≥2), and obstructive CAD (stenosis ≥50%). LVMD was defined by ROC analysis. INOCA group were followed up for the occurrence of major adverse cardiac events (MACEs: cardiovascular death, non-fatal myocardial infarction, revascularization, stroke, heart failure, and hospitalization for unstable angina). Nomogram was established using multivariate Cox regression analysis.

Results

Among 334 patients (118 [35.3%] INOCA), LVMD parameters were significantly higher in INOCA group versus normal group but they did not differ between obstructive CAD groups. In INOCA group, 27 (22.9%) MACEs occurred during a 26-month median follow-up. Proportion of LVMD was significantly higher with MACEs under both stress (63.0% vs. 22.0%, P &lt; 0.001) and rest (51.9% vs. 20.9%, P = 0.002). Kaplan–Meier analysis revealed significantly higher rate of MACEs (stress log-rank: P = 0.002; rest log-rank: P &lt; 0.001) in LVMD patients. Multivariate Cox regression analysis showed that stress LVMD (HR: 3.82; 95% CI: 1.30–11.20; P = 0.015) was an independent predictor of MACEs. The internal bootstrap resampling approach indicates that the C-index of nomogram was 0.80 (95% CI: 0.71–0.89) and the AUC values for 1 and 3 years of risk prediction were 0.68 (95% CI: 0.46–0.89) and 0.84 (95% CI: 0.72–0.95), respectively.

Conclusion

LVMD-based nomogram might provide incremental prognostic value and improve the risk stratification in INOCA patients.

Diastolic dyssynchrony assessment by gated myocardial perfusion-SPECT in subjects who underwent cardiac resynchronization therapy

BACKGROUND

Left ventricular diastolic dyssynchrony (LVDD) can be assessed by gated myocardial perfusion single-photon emission computed tomography (GMP-SPECT). LVDD is an area of interest in subjects who underwent cardiac resynchronization therapy (CRT). The aim of this post hoc analysis was to assess the role of LVDD in subjects with CRT who were followed up at 6-month period.

MATERIAL & METHODS

Left ventricular diastolic dyssynchrony was assessed by GMP-SPECT at baseline and after CRT procedure in 160 subjects from 10 different cardiological centers. CRT procedure was performed as per current guidelines. Outcomes were defined as improvement in ≥1 New York Heart Association (NYHA) class, left ventricular ejection fraction (LVEF) by 5%, and reduction in end-systolic volume (ESV) by 15% and 5% points in Minnesota Living with Heart Failure Questionnaire. LVDD was defined as diastolic phase standard deviation ≥40 ± 14°.

RESULTS

Improvement in NYHA functional class occurred in 105 (65.6%), LVEF in 74 (46.3%), decrease in ESV in 86 (53.8%), and Minnesota score in 85 (53.1%) cases. Baseline LV diastolic standard deviation was 53.53° ± 20.85 and at follow-up 40.44° ± 26.1283; (P < 0.001). LVDD was not associated with improvement in clinical outcomes at follow-up.

CONCLUSION

CRT improves both systolic and diastolic dyssynchrony values at 6-month follow-up. LVDD at baseline is correlated with cardiac functionality at follow-up, but not with overall favorable clinical outcomes.

Heart failure with mid-range ejection fraction: pro and cons of the new classification of Heart Failure by European Society of Cardiology guidelines

Currently, the assessment of left ventricular ejection fraction (LVEF) is the cornerstone of the classification of patients with heart failure (HF). The mid-range LVEF (HFmrEF) category was identified in an attempt to uncover specific characteristics of these patients. So far, the analysis of trials, registries, and observational studies have demonstrated that patients with mid-range LVEF belong to a patient cohort with generally intermediate clinical profile as compared with other groups but with a remarkable variety of intrinsic phenotypes. This is due to the limitations of LVEF as the sole criterion to categorize patients with HF and characterize their prognosis, above all when it is >40%. To better define the HFmrEF phenotype, it is reasonable to consider other parameters, such as LVEF changes over time, HF aetiology, co-morbidities, and other imaging parameters. A multiparametric evaluation may contextualize a patient with HFmrEF in a more defined phenotype with a specific prognosis.