Mechanical Dyssynchrony Research Articles

Myocardial work and energy loss of left ventricle obtained by pressure-strain loop and vector flow mapping: a new perspective on idiopathic left bundle branch block

To date, no research has been conducted on the electrical activity and mechanical dyssynchrony of idiopathic left bundle branch block (iLBBB) with normal left ventricular ejection fraction (LVEF). This study sought to assess the left ventricular summation of energy loss (EL-SUM) and average energy loss (EL-AVE) using vector flow mapping as well as myocardial work using pressure-strain loop (PSL) in patients with iLBBB and normal LVEF. We prospectively recruited 35 patients with iLBBB and 35 control participants with normal LVEF. Echocardiography was performed. Conventional echocardiographic parameters, myocardial work, and energy loss (i.e., the EL-SUM and EL-AVE) were calculated. In relation to global myocardial work, compared to the control participants, the iLBBB patients showed decreased global longitudinal strain (GLS; -15.32%±2.58% vs. -18.27%±2.12%; P=0.001), a decreased global work index (GWI; 1,428.24±338.18 vs. 1,964.87±264.16 mmHg%; P<0.001), decreased global work efficiency (GWE) (84.48±5.19 vs. 91.73±5.31 mmHg%; P<0.001), and significantly increased global waste work (GWW; 341.60±132.62 vs. 161.80±106.81 mmHg%; P<0.001). In relation to the regional index, the iLBBB patients had a significantly reduced basal anteroseptal segment (879.15±370.50 vs. 1,746.38±154.44 mmHg%; P<0.001), basal inferoseptal segment (1,111.42±389.04 vs. 1,677.25±223.10 mmHg%; P<0.001), mid-anteroseptal segment (1,097.54±394.83 vs. 1,815.06±291.22 mmHg%; P<0.001), mid-inferoseptal segment (1,012.54±353.33 vs. 1,880.88±254.39 mmHg%; P<0.001), apical anterior segment (1,592.42±366.64 vs. 1,910.00±170.27 mmHg%; P=0.001), apical lateral segment (1,481.62±342.95 vs. 1,817.19±227.55 mmHg%; P=0.001), apical septal segment (1,437.65±428.22 vs. 1,852.25±275.19 mmHg%; P=0.001), and apex (1,542.62±342.89 vs. 1,907.06±197.94 mmHg%; P<0.001). The iLBBB patients had increased EL-AVE and EL-SUM during the late-diastole, isovolumic-systole, and rapid-ejection periods [EL-AVE in T2: 28.3 (8.7, 49.0) vs. 6.8 (5.4, 9.4) J/(s·m3); P=0.029]; [EL-AVE in T3: 24.7 (13.0, 46.8) vs. 7.2 (5.4, 10.8) J/(s·m3), P<0.001]; [EL-AVE in T4: 18.3 (12.0, 27.6) vs. 7.7 (4.1, 11.6) J/(s·m3), P=0.002]; [EL-SUM in T2: 8.3 (2.2, 14.5) vs. 2.1 (1.6, 3.2) J/(s·m), P=0.049]; [EL-SUM in T3: 7.6 (4.0, 14.5) vs. 2.2 (1.7, 3.3) J/(s·m), P<0.001]; [EL-SUM in T4: 5.3 (3.6, 9.7) vs. 2.2 (1.4, 3.0) J/(s·m), P=0.004]. The GWI and GWE were reduced in patients with iLBBB, especially in the septum and apex. The EL-SUM and EL-AVE were higher in patients with iLBBB during the late-diastole, isovolumic-systole, and rapid-ejection periods. EL and PSL reflect the LV hemodynamics of patients with iLBBB.

Impaired cardiac mechanical synchrony revealed with increased myocardial work in women with advanced age

BackgroundWhether the synchronous nature of the myocardium is sex-dependent or affected by the aging process remains unknown. This study aimed to determine the influence of sex and age on cardiac mechanical synchrony during controlled hemodynamic stress. MethodsTransthoracic speckle-tracking echocardiography analyses and central hemodynamics were assessed at rest and during moderate- to high-intensity exercise in healthy young (<45 yr) and older (≥45 yr) women (n = 32) and men (n = 34) matched by age, physical activity and exercise capacity. Left ventricular mechanical dyssynchrony (LVMD) was determined as the time to peak standard deviation (TPSD) of longitudinal and transverse strain and strain rates (LSR, TSR). ResultsPhysical activity, aerobic capacity, heart rate, blood pressure and LVMD at rest were similar between women and men in each age group (P > 0.05). The rate pressure product, an index of myocardial work, did not differ between sex and age groups at rest and during exercise at a given percentage of peak heart rate (P > 0.05). A consistent age effect was observed for transverse LVMD (P-for-age ≤ 0.011). Specifically, older women presented with marked increments (≥42 %) in TSR TPSD at all exercise levels compared with younger women (P ≤ 0.005). Sex per se did not generally affect LVMD. ConclusionA prevailing impairment of cardiac mechanical synchrony in the transverse axis of the left ventricle is revealed during conditions of elevated hemodynamic stress in women with advanced age.

Myocardial Contractility Pattern Characterization in Radiation-Induced Cardiotoxicity Using Magnetic Resonance Imaging: A Pilot Study with ContractiX.

Radiation therapy (RT) plays an integral role in treating thoracic cancers, despite the risk of radiation-induced cardiotoxicity. We hypothesize that our newly developed magnetic resonance imaging (MRI)-based contractility index (ContractiX) is a sensitive marker for early detection of RT-induced cardiotoxicity in a preclinical rat model of thoracic cancer RT. Adult salt-sensitive rats received image-guided heart RT and were imaged with MRI at 8 weeks and 10 weeks post-RT or sham. The MRI exam included cine and tagging sequences to measure left-ventricular ejection fraction (LVEF), mass, myocardial strain, and ContractiX. Furthermore, ventricular torsion, diastolic strain rate, and mechanical dyssynchrony were measured. Statistical analyses were performed between the sham, 8 weeks post-RT, and 10 weeks post-RT MRI parameters. The results showed that both LVEF and myocardial mass increased post-RT. Peak systolic strain and ContractiX significantly decreased post-RT, with a more relative reduction in ContractiX compared to strain. ContractiX showed an inverse nonlinear relationship with LVEF and continuously decreased with time post-RT. While early diastolic strain rate and mechanical dyssynchrony significantly changed post-RT, ventricular torsion changes were not significant post-RT. In conclusion, ContractiX measured via non-contrast MRI is a sensitive early marker for the detection of subclinical cardiac dysfunction post-RT, and it is superior to other MRI cardiac measures.

Beta-blockers and mechanical dyssynchrony in heart failure assessed by radionuclide ventriculography

BackgroundRadionuclide ventriculography (RNVG) can be used to quantify mechanical dyssynchrony and may be a valuable adjunct in the assessment of heart failure with reduced ejection fraction (HFrEF). The study aims to investigate the effect of beta-blockers on mechanical dyssynchrony using novel RNVG phase parameters. MethodsA retrospective study was carried out in a group of 98 patients with HFrEF. LVEF and dyssynchrony were assessed pre and post beta-blockade. Dyssynchrony was assessed using synchrony, entropy, phase standard deviation, approximate entropy, and sample entropy from planar RNVG phase images. Subgroups split by ischemic etiology were also investigated. ResultsAn improvement in dyssynchrony and LVEF was measured six months post beta-blockade for both ischemic and non-ischemic groups. ConclusionsA significant improvement in dyssynchrony and LVEF was measured post beta-blockade using novel measures of dyssynchrony.

Оцінка механічної диссинхронії міокарду у хворих з різними формами коронарної хвороби серця, яким проводилась реваскуляризація

The purpose of the study was to determine the presence of mechanical dyssynchrony of the myocardium in patients with various clinical variants of coronary heart disease undergoing revascularization. Materials and methods. 137 patients (106 men and 31 women, aged from 31 to 81 years) took part in the study, including 121 patients with coronary heart disease who underwent a revascularization procedure. Results and discussion. The frequency of detection of mechanical dyssynchrony of the myocardium is significantly higher in patients with coronary heart disease compared to patients without coronary heart disease who underwent revascularization (41.3% vs. 6.2%, respectively). Aortic transit time was significantly and significantly greater in the group of patients with coronary heart disease compared to patients without coronary heart disease, while pulmonary transit time was the same in the comparison groups. Accordingly, this caused a significant difference in interventricular mechanical delay. Left ventricular filling time was significantly shorter in the group of patients with coronary heart disease and, conversely, left ventricular ejection time was shorter in the group of patients without coronary heart disease. The study showed a significant increase in the frequency of myocardial dyssynchrony in patients with coronary heart disease who underwent revascularization, which creates conditions for studying the prognostic value in relation to the clinical results of revascularization. The time of advancement to the aorta was significantly and reliably longer in the group of patients with coronary heart disease compared to patients without coronary heart disease, while the time of advancement to the pulmonary artery was the same in the comparison groups, which caused a significant difference in the interventricular mechanical delay and confirms dependence of the development of myocardial dyssynchrony on the localization of the coronary artery lesion. Conclusion. Indicators of diastolic dysfunction of the left ventricular myocardium, although there was a tendency for a difference between the group of patients with coronary heart disease and the comparison group, this tendency was unreliable, which demonstrated their later change in relation to the indicators of myocardial dyssynchrony. The data obtained by us confirm the greater informativeness of mechanical dyssynchrony of the left ventricle indicators in comparison with indicators that characterize diastolic function and their earlier changes in patients with coronary heart disease. In turn, early detection and treatment of mechanical dyssynchrony of the left ventricle can delay the onset of left ventricular dysfunction in patients with coronary heart disease

Left Ventricular Dysfunction Following the Ross-Konno Reconstruction is Independent of the Operation.

The Ross-Konno (RK) operation is a well-established surgical treatment for combined left ventricular outflow tract obstruction and aortic valve pathology in children. Prior study has demonstrated that mechanical and electrical dyssynchrony exist post-RK compared to normal controls. The purpose of this study was to evaluate myocardial function pre- and post-RK as defined by echocardiography.Patients undergoing the RK operation (n = 13; median age: 1.3years; range: 0.5-13.3years) were evaluated by echocardiography at defined timepoints: pre-RK, post-RK, 1-year post-RK, and 2years post-RK. Defined parameters of left ventricular performance were analyzed: systolic mechanical dyssynchrony (M-Dys), global left ventricular circumferential strain (GCS), and diastolic relaxation fraction (DRF). Patients with post-operative atrioventricular block (n = 6) were analyzed separately.No pre- versus post-RK differences existed in M-Dys, GCS, or DRF in patients both with and without post-RK atrioventricular block. Further, 1- and 2-year follow-up post-RK demonstrated significant heterogeneity in evaluated parameters of function with no pre- and post-RK differences in M-Dys, GCS, or DRF.Mechanical dyssynchrony exists post-RK reconstruction in both short- and long-term follow-up yet these echocardiographic parameters of ventricular performance are independent of the RK operation. Further study is, therefore, warranted to define causal relationships for observed short- and long-term ventricular dysfunction post-RK as the findings of the present study suggest a deleterious mechanism apart from the technical RK reconstruction.

Abstract 10515: Mechanical Dyssynchrony in Patients With a Fontan Circulation and Its Relationship to Outcomes

Introduction: The prevalence and significance of mechanical dyssynchrony is not well known in the Fontan population. Methods: Single-center, retrospective analysis of CMRs in Fontan patients compared to healthy controls. Feature tracking was performed on all slices of a short-axis cine stack and dyssynchrony index (DI) was defined as the standard deviation of time-to-peak circumferential strain for all segments. A composite outcome was defined as death, heart transplant listing, or new ventricular arrhythmias. Results: A total of 512 cases (17±9 y) and 42 controls (16±9 y) were included. Figure 1 depicts differences in EDV i , EF, DI, and QRS duration between the cohorts. DI correlated with EDV i (r=0.35; p&lt;0.01), EF (r=-0.29; p&lt;0.01), and QRS duration (r=0.29; p&lt;0.01). At a median follow-up of 4.2 yrs, 10% had death or transplant listing and 4% had ventricular arrhythmias. RV dominance, EDV i , EF, DI, and QRS interval were associated with increased risk of the composite outcome (Table 1). Figure 2 demonstrates a significantly higher probability of the composite outcome in those with EDV i &gt;120 ml/m 2 and DI&gt;70 ms. Conclusion: Fontan patients have more mechanical dyssynchrony and longer QRS duration compared to controls. These abnormalities are more pronounced in RV or mixed ventricular morphology and are associated with a higher risk of ventricular arrhythmias, transplant listing, or death.

Does types of atrial fibrillation matter in the impairment of global and regional left ventricular mechanics and intra-ventricular dyssynchrony?

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, which is associated with cardiac dysfunction. This study aimed to compare the impairment severity of left ventricular strain and intra-ventricular dyssynchrony using echocardiography-derived velocity vector imaging in patients with different types of AF without heart failure. 168 non-valvular AF patients with normal left ventricular ejection fraction (98 paroxysmal AF patients and 70 persistent AF patients) and 86 healthy control subjects were included in this study. Regional and global left ventricular longitudinal and circumferential strain were measured. Time to regional peak longitudinal strain was measured and the standard deviation of all 12 segments (SDT-S) was used as a measure of intra-ventricular dyssynchrony. Significantly lower GLS (-18.71 ± 3.00% in controls vs. -17.10 ± 3.01% in paroxysmal AF vs. -12.23 ± 3.25% in persistent AF, P < 0.05) and GCS (-28.75 ± 6.34% in controls vs. -24.43 ± 6.86% in paroxysmal AF vs. -18.46 ± 6.42% in persistent AF, P < 0.01) were observed in either persistent AF subjects or paroxysmal AF subjects compared with healthy control subjects (P < 0.05). The impairment was much worse in persistent AF subjects compared with paroxysmal AF subjects (P < 0.001). Intraventricular dyssynchrony was found in both persistent AF patients and paroxysmal AF patients, and it's worse in persistent AF patients (52 ± 18 ms in controls, 61 ± 17 ms in paroxysmal AF, and 70 ± 28 ms in persistent AF, P < 0.05). Multivariate regression analysis revealed AF types were independent risk factors of GLS, GCS, and intraventricular dyssynchrony. AF types were not only associated with impaired longitudinal and circumferential left ventricle mechanics but also intra-ventricular mechanical dyssynchrony. Worse systolic mechanics and intra-ventricular dyssynchrony were found in patients with persistent AF compared with these in patients with paroxysmal AF.

Cardiac magnetic resonance imaging in patients with left bundle branch block: Patterns of dyssynchrony and implications for late gadolinium enhancement imaging.

Left bundle branch block (LBBB) is a ventricular conduction delay with high prevalence. Aim of our study is to identify possible recurring patterns of artefacts in late gadolinium enhancement (LGE) imaging in patients with LBBB who undergo cardiac magnetic resonance imaging (MRI) and to define parameters of mechanical dyssynchrony associated with artefacts in LGE images. Fifty-five patients with LBBB and 62 controls were retrospectively included. Inversion time (TI) scout and LGE images were reviewed for artefacts. Dyssynchrony was identified using cardiac MRI by determining left ventricular systolic dyssynchrony indices (global, septal segments, and free wall segments) derived from strain analysis and features of mechanical dyssynchrony (apical rocking and septal flash). Thirty-seven patients (67%) with LBBB exhibited inhomogeneous myocardial nulling in TI scout images. Among them 25 (68%) patients also showed recurring artefact patterns in the septum or free wall on LGE images and artefacts also persisted in 18 (72%) of those cases when utilising phase sensitive inversion recovery. Only the systolic dyssynchrony index of septal segments allowed differentiation of patient subgroups (artefact/no artefact) and healthy controls (given as median, median ± interquartile range); LBBB with artefact: 10.44% (0.44-20.44%); LBBB without artefact: 6.82% (-2.18-15.83%); controls: 4.38% (1.38-7.38%); p < 0.05 with an area under the curve of 0.863 (81% sensitivity, 89% specificity). Septal flash and apical rocking were more frequent in the LBBB with artefact group than in the LBBB without artefact group (70 and 62% versus 33 and 17%; p < 0.05). Patients with LBBB show recurring artefact patterns in LGE imaging. Use of strain analysis and evaluation of mechanical dyssynchrony may predict the occurrence of such artefacts already during the examination and counteract misinterpretation.

Can echocardiography facilitate decision-making to CRT?

Abstract Introduction Cardiac resynchronization therapy (CRT) remains underused despite its well-established therapeutic effect and clear guidelines. Among various reasons are the lack of referral, the fear of complications and the high therapy cost. The assessment of mechanical dyssynchrony (MD) on echocardiography has been suggested to aid patient selection. In the past, however, several studies have used old markers of MD producing disappointing results and the use of echocardiography for patient selection became discredited. Promising new markers have been developed since and could aid clinical decision-making for CRT. These should, however, first be thoroughly tested and compared to the old markers. Purpose (I) To confirm the relevance of the new markers of MD for survival free of cardiac death and (II) to compare old and new markers of MD for predicting cardiac death within 5 years post-CRT in patients eligible for CRT according the 2021 ESC guidelines. Methods 222 CRT-patients were analysed retrospectively in a multicentre setting. MD was assessed using three old markers: septal-to-posterior wall-motion-delay (SPWMD), left-ventricular-filling-time/cardiac-cycle ratio (LVFT/RR), and intraventricular mechanical delay (IVMD); and three new markers: systolic stretch index (SSI), myocardial work index (MWI), and visual presence of septal flash or apical rocking (SFoAR). For each marker, patients were categorized using previously published cut-offs as “MD present” (Yes) or “MD not present” (No). Log rank tests were performed on Kaplan-Meier curves for survival free of cardiac death. Cox proportional hazards regressions were used to compute the hazard-ratio (HR) for cardiac death within 5 years after implantation. Results Cardiac death occurred in 37 patients (17%). Patients with MD before CRT according to IVMD (p=0.003), SSI (p&amp;lt;0.001), MWI (p&amp;lt;0.001) or SFoAR (p&amp;lt;0.001) had a significantly better survival. The hazard ratios were 0.34 (95% CI, 0.19–0.75) for IVMD, 0.30 (95% CI, 0.15–0.57) for SSI, 0.26 (95% CI, 0.12–0.54) for MWI and, 0.28 (95% CI, 0.14–0.53) for SFoAR. The other markers for MD were not significant for survival. Conclusion The new markers for dyssynchrony are better than the old. Patients with mechanical dyssynchrony on echocardiography before CRT according to SSI, MWI or SFoAR are 3 to 4 times less likely to die within 5 years after CRT implantation. The presence of one of these markers in patients with a broad QRS (≥130ms) and reduced LVEF (≤35%) should prompt clinicians to refer for or to proceed to CRT. Funding Acknowledgement Type of funding sources: None.

Mechanical dyssynchrony, a novel marker to predict long-term survival in patients with cardiac resynchronization

Abstract Background Cardiac resynchronization therapy (CRT) is an established therapy in patients with symptomatic heart failure with reduced left ventricular ejection fraction (LVEF &amp;lt;35%) (HFrEF) that have conduction disturbances as measured by prolonged QRS duration of &amp;gt;130 ms. Mechanical dyssynchrony (MD) in echocardiography has not proven benefit to determine CRT indication, but is hypothesized to be of predictive value. Both MD aspects of “apical rocking” (AR) but also “septal flash” (SF) have been shown to be a predictive value in short- and medium-term follow-up in CRT, but no trial has tested long-term effects yet. Purpose This study investigated the impact of AR and SF on long-term survival in CRT recipients. Methods and results 425 HFrEF patients (mean age: 63.0±10.6 years, 72.3% male, 60.7% non-ischemic etiology) with ESC guideline-derived CRT indication have been implanted and additionally investigated for MD markers at baseline as well as after a 11.5±8.0 months follow-up including long-term survival. Herein AR and/or SF were identified in 307 (72,2%) participants at baseline. During follow-up both AR and/or SF disappeared in 256 (83.4%) patients through CRT use. The overall mean survival was 95.9±52.9 months. Univariable analysis showed beneficial survival for women over men (109.1±52.4 vs. 90.9±52.4 months; p&amp;lt;0.001). Moreover, younger (&amp;lt;60 years) patients profit more than older patients (110.6±53.7 vs. 88.6±51.1 months; p&amp;lt;0.001). Interestingly, patients with MD markers at baseline generally had an improved overall survival (106.2±52.0 vs. 68.9±45.4 months; p&amp;lt;0.001), and in addition to that we found the best survival in patients with disappeared over persisting mechanical dyssynchrony echocardiography parameters in CRT (111.6±51.2 vs. 79.7±47.6 months p&amp;lt;0.001). Multivariate analysis shows age and presence of MD at baseline to be powerful predictors for long-term survival in CRT HFrEF patients (Figures 1 and 2). Conclusion Novel echocardiography MD parameters before CRT implantation predict long-term survival. Moreover, long-term survival even further improves when AR and/or SF disappear through CRT in HFrEF. Our results encourage a prospective, randomized, controlled, multicenter trial to study clinical implementation of MD in CRT patients. Funding Acknowledgement Type of funding sources: None.

Left bundle branch pacing is superior in preserving ventricular mechanical synchrony and cardiac function than right ventricular pacing: a two-center experience

Abstract Background Left bundle branch pacing (LBBP) has emerged as a novel pacing modality. Although it has been proved to maintain electrical synchrony better than right ventricular pacing (RVP), little is known about the impact on mechanical synchrony. This study investigates if LBBP preserves mechanical synchrony and cardiac function better compared to conventional (CRVP) and leadless (LRVP) RVP. Methods Sixty-five patients with pacing indication for bradycardia were prospectively enrolled: Twenty-two were treated with LBBP, 23 with CRVP and 20 with LRVP. All patients underwent echocardiography before and after implantation and at one-year follow-up. Left ventricular (LV) volumes, ejection fraction (EF) and global longitudinal strain (GLS) were measured. Regional septal (SW) and lateral wall work (LW) was calculated as the average from the respective basal and mid-ventricular segments in the apical four-chamber and three-chamber view. The lateral-septal work difference (LSWD) was used as a measure of mechanical dyssynchrony. Results At baseline, the QRS duration and LSWD were similar in all three groups. During follow-up, the QRS duration increased least in LBBP compared to CRVP and LRVP (+28.1±18.3ms vs +58.2±31.4 and 47.1±26.1ms, both P&amp;lt;0.01). SW was markedly decreased in CRVP and LRVP while LW work remained unchanged, resulting in a large LSWD compared to LBBP (1308.4±732.9 mmHg*% and 1451.3±606.1 mmHg*% vs. 286.0±479.9mmHg*%, both P&amp;lt;0.001). During one year follow-up, LVEF and LV GLS decreased more in CRVP compared to LBBP (both P&amp;lt;0.05). Conclusion LBBP causes less LV dyssynchrony than CRVP and LRVP as it preserves a more physiologic conduction pattern. With this, LBBP appears to preserve LV function better than CRVP. CRVP and LRVP did not differ in mechanical dyssynchrony or LV remodelling. Funding Acknowledgement Type of funding sources: None.

Post-systolic shortening index by echocardiography evaluation of dyssynchrony in the non-dilated and hypertrophied left ventricle

Abstract Background Post-systolic shortening index (PSI) is defined as myocardial shortening that occurs after aortic valve closure, and is an emerging measure of regional LV contractile dysfunction. PSI measurement variability amongst software vendor and its relationship with mechanical dyssynchrony and mechanical dispersion index (MDI) remains unknown. We evaluated PSI by speckle-tracking echocardiography from several vendors in patients with increased left ventricular wall thickness, and associations with MDI. Methods This is a prospective cross-sectional study of 70 patients (36 hypertrophic cardiomyopathy [HCM], 18 cardiac amyloidosis and 16 healthy controls) undergoing clinically indicated echocardiography. PSI was measured using QLAB/aCMQ (Philips), QLAB/LV auto-trace (Philips), EchoPAC (GE), Velocity Vector Imaging (Siemens), and EchoInsight (EPSILON) software packages, and calculated as 100% × (post systolic strain − end-systole strain)/post systolic strain. Results There was a significant difference in mean PSI among controls 2.1±0.6%, HCM 6.1±2.6% and cardiac amyloidosis 6.8±2.7% (p&amp;lt;0.001). Variations between software vendors were significant in patients with pathologic increases in LV wall thickness (for HCM p=0.03, for amyloidosis p=0.008), but not in controls (p=0.11), as seen in Figure 1. Furthermore, there were moderate correlations between PSI and both MDI (r=0.77) and left ventricular global longitudinal strain (r=0.69), as seen in Figure 2. Conclusion PSI was greater in HCM and cardiac amyloidosis patients than controls, and a valuable tool for dyssynchrony evaluation, with moderate correlations to MDI and strain. However, there were significant variations in PSI measurements by software vendor especially in patients with pathological increase in LV wall thickness, suggesting that separate vendor-specific thresholds for abnormal PSI are required. Funding Acknowledgement Type of funding sources: None.

Impact of diabetes mellitus in non-ischemic dilated cardiomyopathy: focus on diastolic dysfunction

Abstract Introduction In patients with diabetes mellitus (DM), the presence of myocardial dysfunction in the absence of coronary artery disease, valvular disease and other conventional cardiovascular risk factors has been defined as diabetic cardiomyopathy. Left ventricle concentric hypertrophy and myocardial fibrosis are the structural hallmarks that lead to overt diastolic dysfunction. The impact of DM in imaging features and clinical outcomes of patients with non-ischaemic dilated cardiomyopathy (DCM) has not been completely elucidated yet. Purpose We aim to describe advance imaging and clinical characteristics of DCM's patients with DM, and its potential impact on cardiac morphology and function in comparison to non-diabetic patients. Methods From 2014 to 2021, all patients with DCM were prospectively evaluated in our tertiary care hospital. All patients underwent a transthoracic echocardiogram and 165 patients underwent a 1.5 Tesla scanner cardiac magnetic resonance (CMR) as part of the diagnostic workup. Left ventricle ejection fraction (LVEF), mechanical dyssynchrony, and diastolic function were analyzed according to current guidelines. Late gadolinium enhancement (LGE) was assessed visually and its extent was calculated as the number of affected myocardial segments. Heart failure (HF) hospitalizations, arrhythmic events and mortality were assessed during follow-up. Results The median age of our cohort (n=227) was 61.6 (14.7) years, 66% were male, and DM was present in 57 patients (25.1%). Mean follow-up was 37.6 (33.9) months. Diabetic patients were significantly older, more frequently male, and with more comorbidity. Left bundle branch block was more frequent in patients with DM. The use of SGLT2 inhibitors was higher in diabetic patients (47.4% vs 21.1%; p&amp;lt;0.05). No significant differences were observed regarding other guideline-recommended HF drugs. With regard to imaging features, no significant differences were found in LVEF and global longitudinal strain between the two groups. There was a trend toward a higher left ventricle mass index measured by CMR in diabetic patients (p=0.364). Parameters of mechanical dyssynchrony and diastolic dysfunction were worse in diabetic patients (Table 1). High-risk LGE pattern (defined as the presence of epicardial, transmural or septal plus free-wall LGE) was more frequently observed in the diabetes group (p&amp;lt;0.05). Finally, the diabetic group had a higher incidence of HF hospitalization (45.61% vs 22%, p&amp;lt;0.001) and all-cause mortality (24.6% vs 11.8%, p&amp;lt;0.05), as shown in Figure 1. There was also a trend toward a higher cardiovascular mortality (12.3% vs 6.5%, p=0.164) in this group. Conclusion DM confers a high-risk profile to DCM patients, explained by extracardiac (more comorbidities) and cardiac (more diastolic dysfunction and high-risk LGE pattern) reasons. These patients may benefit from a close monitoring, and new therapies should be developed to improve their prognosis. Funding Acknowledgement Type of funding sources: None.

Biventricular or left univentricular pacing in heart failure patients: is there a better strategy

Abstract Background Cardiac resynchronization therapy (CRT) is a cornerstone in treatment of heart failure (HF) with reduced left ventricular ejection fraction (LVEF) and ventricular dyssynchrony. Biventricular (BiV) pacing is often the preferred method and corrects electrical and mechanical dyssynchrony but Left ventricular (LV) preferential pacing is may preserve conduction via the right bundle branch, preventing deleterious effects from right ventricular. The evidence is sparse and there is doubts whether which programming strategy is better. Purpose We hypothesized that BiV is non-inferior to preferential LV pacing in HF patients with reduced LVEF and CRT devices in cardiovascular death and HF hospitalizations. Methods We retrospectively evaluated 147 patients with HF patients with reduced LVEF and CRT devices. Two groups were defined: LV pacing (group 1) and BiV pacing (group 2). Primary outcome was defined as cardiovascular death and secondary outcome as HF hospitalizations and NYHA class after CRT. Results Mean age was 70,26±10,6 years, 68,1% were males and follow-up was 52,22±44,51 months. One hundred and twenty six (85,7%) patients had implantable cardiac resynchronization therapy (CRT) defibrillator (CRT-D) and 21 (14,3%) CRT pacemaker (CRT-P). Mean LVEF was 31,1±8,5% and mean QRS duration before CRT implantation was 149,5±48,6 ms. Thirty-nine (36,4%) patients were in NYHA III–IV. HF aetiology was idiopathic in 51 (47,2%), ischemic in 36 (33,3%) and alcoholic cardiomyopathy in 9 (8,3%). Forty-five (40,5%) patients had atrial fibrillation and 37 (35,6%) coronary disease. Patients in group 2 were more frequently males than group 1 patients (46 (78,0%) vs 32 (56,1%) respectively, p=0,012). There were no differences in regard to age, LVEF, HF aetiology or other comorbidities between groups. In 57 (49,1%) CRT was programming in preferential LV pacing and 50 (50,9%) in BiV pacing. There were 2 deaths in group 1 and 3 in group 2 (OR 0.80, 95% CI 0.27–2.40). There were 0,98±3,17 hospitalizations per patient and there were no differences in HF hospitalizations between groups (OR 1.01, 95% CI 0.92–1.18) or NYHA after 6 months of CRT (p=0,364). Conclusion BiV pacing was not inferior to LV-only pacing in regard to cardiovascular death, HF hospitalizations and NYHA class improvement. There was no clear advantage for one pacing strategy over the other but more studies are still required. Funding Acknowledgement Type of funding sources: None.

His-pacing and biventricular pacing show similar efficiency in resynchronization and improvements in longitudinal contractile function

Abstract Background The clinical role for HIS-pacing in cardiac resynchronization therapy (HIS-CRT) is promising but is yet to be established. The randomised His-alternative study showed better remodelling with HIS-CRT compared to patients receiving conventional biventricular pacing (BIV-CRT) in the per-protocol-analysis. Purpose In this substudy we investigated whether HIS-pacing was more efficient compared to BIV-CRT in improving mechanical synchrony and longitudinal contractile function. Methods In the His-Alternative study 50 patients with symptomatic heart failure, left ventricular ejection fraction (LVEF) ≤35% and Left bundle branch block were randomized 1:1 to His-CRT or BiV-CRT and followed for 6 months. At implantation, 7 patients crossed over from His-pacing to LV-pacing in the His-CRT group and 1 patient crossed over from LV-pacing to His-pacing in the BiV-CRT group. All patients had echocardiography performed including 2D-strain echocardiography to asses global systolic longitudinal deformation (GLS) at baseline and 6 months. Mechanical dyssynchrony was measured as SD of time-to-peak in all 12 segments of the left ventricle (TPS-SD). Results There were no significant differences in baseline characteristics between patients receiving HIS-CRT and BIV-CRT with regard to dyssynchrony and longitudinal systolic strain. LVEF was significantly higher at 6 months (48±8% vs. 42±8%; p&amp;lt;0.05) in the HIS-CRT group. However, GLS did not significantly improve more with HIS-CRT compared to BIV-CRT, (−8.7ms ± 2.0 to −11.1 ms ± 2.0 vs −9.1 ms ± 2.7 to −10.8±2.5 ms ± 2.8, P = ns for difference) and regarding resynchronization measured as TPS-SD there was no significant difference either (110 ms ± 51 to 47 ms ± 10 vs. 115 ms ± 42 to 60 ms ± 21, P = ns for difference). Conclusion In this substudy, HIS-pacing did not prove more efficient than BIV-CRT in resynchronizing the left ventricle, nor did the observed improvement in longitudinal function differ significantly between methods. However, the number of included patients was rather small and larger studies are needed to fully assess the possible benefits of HIS-CRT. Funding Acknowledgement Type of funding sources: None.

Correlation of left ventricular mechanical dyssynchrony in patients with chronic kidney disease using phase analysis of gated single photon emission computed tomography myocardial perfusion imaging

Abstract Background Left ventricular mechanical dyssynchrony (LVMD) possesses deleterious effects that have been neglected in chronic kidney disease (CKD) as a cause of left ventricular dysfunction and further progression to heart failure, possibly contributing to sudden cardiac death in this population. Thus, cardiovascular risk assessment is essential in early stages of CKD as well as in the pre-transplant screening and this can be performed non-invasively by modalities including phase analysis Gated-SPECT myocardial perfusion imaging (MPI). This modality has emerged as a prognostic tool to predict mortality independent of MPI abnormalities as well as assessment of ventricular synchrony. Purpose The goal of this study is to evaluate the relationship of left ventricular mechanical dyssynchrony using phase analysis G-SPECT and chronic kidney disease severity and its predictors. Methods We included 567 patients who underwent one day rest/stress (dipyridamole) 99mTc-sestamibi myocardial perfusion imaging with G-SPECT for the following indications for testing: detection of CAD among asymptomatic patients, risk assessment during pre-operative evaluation for kidney transplantation and evaluation for noncardiac surgery without active cardiac conditions between January 2017 to January 2021. Data was collected including gender, age, risk factors resting heart rate and baseline blood pressure. Gated SPECT-MPI was performed according to the protocol rest followed by stress images (dipyridamole) 99mTc-sestamibi. The rest and stress phase analysis (histogram bandwidth, standard deviation of phase and entropy) parameters were compared between the five stages of chronic kidney disease. Data of the stress-rest difference in dyssynchrony was analyzed using McNemar's test; crude odds ratios and adjusted odds or multivariate analysis were done. Results Advanced CKD (Stage 4–5) shows statistically significant correlation with the Histogram bandwidth (HBW) both at stress (p=0.008) and rest (p=0.018), and stress entropy (p=0.007). As for the other stages, LVMD is present with similar results seen with the phase parameters HBW and PSD, the entropy values at rest than at stress for Stages I to IV (p&amp;lt;0.05). On further analysis, abnormal perfusion showed to be an independent predictor of left ventricular mechanical dyssynchrony across all arms. Other associated factors includes advanced CKD (stages 4–5), male sex, BMI ≥30 kg/m2, blood pressure and resting heart rate were significantly associated with increased odds of dyssynchrony across stress and rest tests. Overall, the full models were statistically significant, with R-squared ranging from 14.96% to 30.11% (p&amp;lt;0.001). Conclusion This study showed that CKD patients have left ventricular mechanical dyssynchrony on gated-SPECT MPI. Hence, it can be used as an alternative for early assessment and guide decision making for the treatment of patients with CKD to prevent further cardiovascular complication. Funding Acknowledgement Type of funding sources: None.

Predictive values of left ventricular mechanical dyssynchrony for CRT response in heart failure patients with different pathophysiology

BackgroundCardiac resynchronization therapy (CRT) patients with different pathophysiology may influence mechanical dyssynchrony and get different ventricular resynchronization and clinical outcomes. MethodsNinety-two dilated cardiomyopathy (DCM) and fifty ischemic cardiomyopathy (ICM) patients with gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI) were included in this retrospective study. Patients were classified based on the concordance between the left ventricular (LV) lead and the latest contraction or relaxation position. If the LV lead was located on or adjacent to both the latest contraction and relaxation position, the patient was categorized into the both match group; if the LV lead was located on or adjacent to the latest contraction or relaxation position, the patient was classified into the one match group; if the LV lead was located on or adjacent to neither the latest contraction nor relaxation position, the patient was categorized to the neither group. CRT response was defined as ≥5% improvement of LV ejection fraction at the 6-month follow-up. Variables with P < .05 in the univariate analysis were included in the stepwise multivariate model. ResultsDuring the follow-up period, 58.7% (54 of 92) for DCM patients and 54% (27 of 50) for ICM patients were CRT responders. The univariate analysis and stepwise multivariate analysis showed that QRS duration, systolic phase bandwidth (PBW), diastolic PBW, diastolic phase histogram standard deviation (PSD), and left ventricular mechanical dyssynchrony (LVMD) concordance were independent predictors of CRT response in DCM patients; diabetes mellitus and left ventricular end-systolic volume were significantly associated with CRT response in ICM patients. The intra-group comparison revealed that the CRT response rate was significantly different in the both match group of DCM (N = 18, 94%) and ICM (N = 24, 62%) patients (P = .016). However, there was no significant difference between DCM and ICM in the one match and neither group. For the inter-group comparison, Kruskal-Wallis H-test revealed that CRT response was significantly different in all the groups of DCM patients (P < .001), but not in ICM patients (P = .383). ConclusionsCompared with ICM patients, systolic PBW, diastolic PBW and PSD have better predictive and prognostic values for the CRT response in DCM patients. Placing the LV lead in or adjacent to the latest contraction and relaxation position can improve the clinical outcomes of DCM patients, but it does not apply to ICM patients.

The assessment of left ventricular mechanical dyssynchrony from gated 99mTc-tetrofosmin SPECT and gated 18F-FDG PET by QGS: a comparative study

BackgroundDue to partly conflicting studies, further research is warranted with the QGS software package, with regard to the performance of gated FDG PET phase analysis as compared to gated MPS as well as the establishment of possible cut-off values for FDG PET to define dyssynchrony. MethodsGated MPS and gated FDG PET datasets of 93 patients were analyzed with the QGS software. BW, Phase SD, and Entropy were calculated and compared between the methods. The performance of gated PET to identify dyssynchrony was measured against SPECT as reference standard. ROC analysis was performed to identify the best discriminator of dyssynchrony and to define cut-off values. ResultsBW and Phase SD differed significantly between the SPECT and PET. There was no significant difference in Entropy with a high linear correlation between methods.There was only moderate agreement between SPECT and PET to identify dyssynchrony. Entropy was the best single PET parameter to predict dyssynchrony with a cut-off point at 62%. ConclusionGated MPS and gated FDG PET can assess LVMD. The methods cannot be used interchangeably. Establishing reference ranges and cut-off values is difficult due to the lack of an external gold standard. Further prospective research is necessary.

Impact of right ventricular lead position on left ventricular functions and early remodeling in permanent single- and dual-chamber pacemakers.

Right ventricular (RV) apical pacing can induce both interventricular dyssynchrony and intraventricular dyssynchrony. Mechanical dyssynchrony after long-term RV apical pacing is associated with reduced left ventricular (LV) systolic function and deterioration in functional capacity. We aimed to identify the short-term effects of the pacemaker RV lead position on remodeling of LV systolic functions. The study included 30patients who presented with an indication of permanent pacing and who underwent permanent single- or dual-chamber pacemaker insertion: 15patients with RV apical pacing (RV apex), and 15patients with non-apical pacing (mid-septal). The two-dimensional (2D)speckle tracking imaging technique was used for quantification of global longitudinal function of the left ventricle and dyssynchrony evaluation before pacemaker implantation and after a3-month follow-up. At the 3‑month follow-up, post-pacing 2Dspeckle tracking echocardiography revealed impairment of global longitudinal strain in all patients and intraventricular dyssynchrony was significantly increased in the apical location compared with the non-apical location (radial dyssynchrony: 108.67 ± 11.68 ms vs. 80.53 ± 8.17 ms, p < 0.001) with a greater difference (50.53 ± 13.30 ms) in the apical location than in the non-apical location (29.87 ± 6.64 ms, p < 0.001). In the short-term follow-up, 2Dspeckle tracking echocardiography showed more radial dyssynchrony in the apical location than in the non-apical location of RV lead. The RV septal pacing is abetter alternative in terms of less dyssynchrony compared to RV apical pacing. Older age, higher percentage of pacing, and device type are prognostic factors for development of pacemaker-induced cardiomyopathy.