Left Ventricular Dyssynchrony Research Articles

Prognostic value of left ventricular mechanical dyssynchrony indices derived from gated myocardial perfusion SPECT in coronary artery disease: a systematic review and meta-analysis.

Left ventricular mechanical dyssynchrony (LVMD) is an important prognostic factor in coronary artery disease. A growing body of evidence indicates that LVMD parameters derived from phase analysis of gated myocardial SPECT may allow risk stratification for future cardiac events. We performed a systematic review and meta-analysis on the prognostic value of LVMD on gated SPECT in patients with coronary artery disease. PubMed, Embase, and the Cochrane library were searched until August 25, 2022, for studies reporting the prognostic value of LVMD on gated SPECT for outcomes of all-cause death, cardiac death, or major adverse cardiovascular event (MACE) in patients with coronary artery disease. Hazard ratios (HRs) and their 95% confidence intervals (CIs) were meta-analytically pooled using a random-effects model. Nine studies (26,750 patients) were included in a qualitative synthesis. Among the SPECT LVMD parameters used in various studies, high phase standard deviation, phase bandwidth, and phase entropy were widely evaluated and reported to be associated with high rates of all-cause death, cardiac death, or MACE. For five studies (23,973 patients) in the quantitative synthesis, the pooled HR of LVMD for predicting MACE was 2.81 (95% CI 2.03-3.88). Studies using combined phase parameters to define LVMD showed higher HRs than a study using phase entropy (p = 0.0180). LVMD from gated myocardial SPECT is a significant prognostic factor for coronary artery disease. Phase analysis of gated SPECT may be useful for accurate risk stratification and could be applied for clinical decision-making in such patients.

The influence of left bundle branch block on myocardial T1 mapping

Tissue characterisation using T1 mapping has become an established magnetic resonance imaging (MRI) technique to detect myocardial diseases. This retrospective study aimed to determine the influence of left bundle branch block (LBBB) on T1 mapping at 1.5 T. Datasets of 36 patients with LBBB and 27 healthy controls with T1 mapping (Modified Look-Locker inversion-recovery (MOLLI), 5(3)3 sampling) were included. T1 relaxation times were determined on mid-cavity short-axis images. R2 maps were generated as a pixel-wise indicator for the goodness of the fit of T1 maps. R2 values were significantly lower in patients with LBBB than in healthy controls (whole myocardium/septum, 0.997, IQR, 0.00 vs. 0.998, IQR, 0.00; p = 0.008/0.998, IQR, 0.00 vs. 0.999, IQR, 0.00; p = 0.027). Manual correction of semi-automated evaluation tended to improve R2 values but not significantly. Strain analysis was performed and the systolic dyssynchrony index (SDIglobal) was calculated as a measure for left ventricular dyssynchrony. While MRI is generally prone to artefacts, lower goodness of the fit in LBBB may be mainly attributable to asynchronous contraction. Therefore, careful checking of the source data and, if necessary, manual post-processing is important. New techniques might improve the goodness of the fit of T1 mapping by reducing sampling in the motion prone diastole of LBBB patients.

Association of epicardial fat volume with subclinical myocardial damage in patients with type 2 diabetes mellitus.

In type 2 diabetes mellitus (T2DM) patients, left ventricular systolic dyssynchrony (LVSD) with normal left ventricular ejection fraction (LVEF) and normal myocardial perfusion could referred to as subclinical myocardial damage, which is difficult to diagnose at an early stage. Epicardial adipose tissue, a distinctive heart-specific visceral fat, is closely related to various cardiovascular diseases. The objective of this study was to investigate the correlation between epicardial fat volume (EFV) and subclinical myocardial damage in T2DM patients. This retrospective cross-sectional study included 117 T2DM patients with normal myocardial perfusion by single photon emission computed tomography-computed tomography (SPECT-CT) and normal LVEF by echocardiography. The study was conducted from January 2018 to December 2022. Patient data were collected through electronic medical records including basic patient information, medical history, laboratory tests, and medication data. The EFV was quantified through a non-contrast CT scan. Quantitative indicators of LVSD including phase standard deviation (PSD) and phase histogram bandwidth (PBW) were obtained through phase analysis of the gated rest myocardial perfusion imaging (MPI). Additionally, 83 healthy individuals at the same time were selected to gain the reference threshold of LVSD indicators (13.1° for PSD and 37.6° for PBW). Univariate and multivariable logistic regression models were performed to analyze factors influencing LVSD. A generalized additive model (GAM) was applied to explore the relationship between EFV and LVSD. The receiver operating characteristic (ROC) curve was used to analyze the diagnostic value of EFV for LVSD. Among all patients, 32 (27.4%) patients had LVSD. Compared with the non-LVSD group, the body mass index (BMI) and EFV were higher in the LVSD group (25.83±2.66 vs. 23.94±3.13 kg/m2; 142.41±44.17 vs. 108.01±38.24 cm3, respectively, both P<0.05). Multivariate regression analysis revealed that EFV was independently associated with LVSD [odds ratio (OR) =1.19; 95% confidence interval (CI): 1.06-1.34; P=0.003]. Age, BMI, incidence of hypertension, and LVSD were increased with tertiles of EFV (all P<0.05). The GAM indicated a linear association between EFV and LVSD. The ROC curve analysis concluded that the area under the curve (AUC) of EFV for predicting subclinical myocardial damage in T2DM patients was 0.732 (95% CI: 0.633-0.831, P<0.001), with the optimal threshold of 122.26 cm3, sensitivity of 71.9%, and specificity of 69.4%. EFV is an independent risk factor for LVSD in T2DM patients with normal LVEF and normal MPI, which could potentially serve as a novel imaging marker and a potential therapeutic target for subclinical myocardial damage.

Effect of His Bundle Pacing on Abnormal Myocardial Fatty Acid and Glucose Metabolism Induced by Right Ventricular Pacing.

Metabolic disorder is noted for pacing-induced cardiomyopathy. The benefits of His bundle pacing over right ventricular (RV) pacing in preventing pacing-induced cardiomyopathy from a metabolic perspective are yet to be fully understood. Three pig groups were established for this study: sham control, RV pacing (RV pacing for 6 months), and His pacing (RV pacing for 6 months, followed by His bundle pacing for 3 months). Complete atrioventricular block was created in the last 2 groups. Left ventricular function and dyssynchrony were assessed via echocardiography, while proteins linked to metabolism, endoplasmic reticulum stress, and inflammation in left ventricular myocardium were examined. The RV pacing group had significantly more left ventricular mechanical dyssynchrony compared with the other groups. The RV pacing group exhibited triglyceride and diacylglycerol accumulation in cardiomyocytes and higher expression of binding immunoglobulin protein and tumor necrosis factor-α than the other groups. Additionally, the expression of CD36 was activated, while the expression of hormone-sensitive lipase was downregulated in the RV pacing group compared with the His pacing and sham control groups. Furthermore, the expressions of GLUT4 and pyruvate dehydrogenase were higher in the RV pacing group than the sham control and His pacing groups. Notably, the abnormal fatty acid and glucose metabolic pathways in the left ventricular myocardium during RV pacing could be corrected by His bundle pacing. His bundle pacing can mitigate the abnormal metabolism disorders, endoplasmic reticulum stress, and inflammation induced during RV pacing and may contribute to the superiority of conduction system pacing over RV pacing in reducing heart failure hospitalization.

Real-time three-dimensional transthoracic echocardiography in quantification of left ventricular dyssynchrony

Aim. To compare endocardial and epicardial left ventricular (LV) pacing using real-time electrocardiography (ECG)-synchronized three-dimensional echocardiography (3DE).Methods. Experimental intraoperative study included 88 points obtained from 12 patients with compensated heart failure of II-IV functional class NYHA (LV ejection fraction &lt; 35%) and cardiac resynchronization therapy indications - ECG pattern of complete left bundle branch block (LBBB) and QRS complex duration &gt; 150 ms. During isolated LV pacing as part of cardiac resynchronization therapy implantation procedure endocardial and epicardial stimulation points matched under fluoroscopic control using quadripolar coronary sinus leads and endocardial electrodes for temporary pacing were obtained. The overall number of corresponding pacing sites included 44 endocardial and 44 epicardial stimulation positions. The mean age of patients was 68.5 [63; 73.5] years, 83% males (n=10). Before study enrollment, 12-channel ECG, echocardiography, and a six-minute walk test were performed for all participants along with cardiac magnetic resonance imaging and control coronary angiography if indicated. The prevalence of coronary heart disease was 50% (n=6) while dilated cardiomyopathy was the most common etiology of chronic heart failure in other cases. Intraoperative ECG with estimation of paced QRS complex morphology at each point was registered via LabSystem Pro Electrophysiological Recording System (Bard Electrophysiology, USA). 3DE was performed using TomTec and Philips Qlab 3DQ Advanced software (Philips Medical Systems, USA).Results. Three-dimensional parametric imaging of LV regional segmental excursion and myocardial contractility using 3DE revealed statistically significant difference in semi-quantative parameters such as ExcAvg (p&lt;0.001), ExcMax (p=0.001), ExcMin (p&lt;0.001) and LV ejection fraction based on 3D modelling (p=0.003) while endocardial pacing was more beneficial. During the course of endocardial stimulation, the 3DE dyssynchrony index estimated at the 2nd stimulation site was also significantly lower (p=0.03). Identical dyssynchrony parameters valid for the 16 and 12-segment 3D models (SDI-16, Tmsv-12SD) (at p=0.06) demonstrated only a tendency for significant difference. The duration of QRS complex at the time of endocardial pacing was significantly shorter (&lt;190 [179;215] ms) (p=0.0008). Semi-quantitative and quantitative 3DE parameters showed the benefit of endocardial pacing resulting in cardiac contractility improvement with less dyssynchrony and LV volume reducing during intraoperative period.Conclusion. Endocardial pacing has potential benefit over the epicardial pacing represented by intraoperative dynamics of LV global and local contractility, intraventricular dyssynchrony estimated by 3DE and also ECG criteria. 3DE is helpful in more precise and reproducibile determing of late activation zone for target LV lead placement that is more manoeuvrable in case of endocardial stimulation.

Left ventricular mechanical dyssynchrony after chemotherapy in breast cancer patients with normal rest gated SPECT-MPI.

Early diagnosis of chemotherapy-induced cardiotoxicity plays an important role in preventing heart failure. The main aim of our study was to assess left ventricular (LV) dyssynchrony measured by phase analysis of gated single-photon emission computed tomography (SPECT) as an early sign of cardiotoxicity after breast cancer chemotherapy. This cross-sectional study was conducted on patients with stage ≤ 3 breast cancer and no history of cardiovascular disease or diabetes. After mastectomy, the patients underwent rest gated SPECT myocardial perfusion imaging (MPI). Sixty patients with normal gated SPECT-MPI were selected and the imaging was performed after chemotherapy with doxorubicin, cyclophosphamide and paclitaxel. LV function and contractility parameters were extracted by QGS software and the results were compared with the t test method. The abnormality of at least one of the three phase analysis indices was considered as left ventricular dyssynchrony (LVD). The average LV end-systolic volume and ejection fraction (LVEF) before and after chemotherapy were (16.2 ± 8.0ml and 21.6 ± 11.6ml) and (73.4 ± 7.9% and 67.5 ± 9.2%) respectively, which showed a significant decrease (P < 0.05). In 2 patients (3.3%), the LVEF decreased to less than 50% after chemotherapy. The average parameters of left ventricular contractility before and after chemotherapy were, respectively, as follows: PHB (24.1 ± 7.5 and 33.8 ± 16.4), PSD (9.4 ± 6.1 and 5.7 ± 1.9) and entropy (28.9 ± 7.1 and 35.6 ± 9.7), which showed a significant increase (P < 0.05). LVD was observed in 14 patients (23.4%) after chemotherapy and prevalence of LVD was significantly higher in patients who had received a cumulative dose of doxorubicin of more than 400mg/m2 (P = 0.005). There was no relationship between age and body mass index with the incidence of LVD after chemotherapy (P > 0.05). Using phase analysis of gated SPECT-MPI, chemotherapy-induced LVD was seen in a significant number of patients with breast cancer, especially with a high cumulative dose of doxorubicin. LVD might indicate chemotherapy-induced cardiotoxicity before LVEF becomes abnormal.

Kiosk 4R-TC-07 - LV Dyssynchrony at Rest and Under Stress: A Semi-quantitative Examination of Heart Failure Patients and Controls via Cardiac MRI

Kiosk 4R-TC-07 - LV Dyssynchrony at Rest and Under Stress: A Semi-quantitative Examination of Heart Failure Patients and Controls via Cardiac MRI

Beyond biventricular pacing: Exploring the advantages of his-bundle pacing and left bundle branch pacing in heart failure-A systematic review and meta-analysis.

This meta-analysis compares His-Purkinje system pacing (HPSP), a novel cardiac resynchronization therapy (CRT) technique that targets the intrinsic conduction system of the heart, with conventional biventricular pacing (BiVP) in heart failure (HF) patients with left ventricular (LV) dysfunction and dyssynchrony. We searched multiple databases up to May 2023 and identified 18 studies (five randomized controlled trials and 13 observational studies) involving 1291 patients. The outcome measures were QRS duration, left ventricular ejection fraction (LVEF) improvement, left ventricular end-diastolic diameter (LVEDD) change, HF hospitalization, and New York Heart Association (NYHA) functional class improvement. We used a random-effects model to calculate odds ratios (OR), and mean differences (MD) with 95% confidence intervals (CI). We also assessed the methodological quality of the studies. The mean LVEF was 30.7% and the mean follow-up duration was 8.1 months. Among LBBP, HBP, and BiVP, HBP provided the shortest QRS duration [MD: -18.84ms, 95% CI: -28.74 to -8.94; p=0.0002], while LBBP showed the greatest improvement in LVEF [MD: 5.74, 95% CI: 2.74 to 7.46; p<0.0001], LVEDD [MD: -5.55mm, 95% CI: -7.51 to -3.59; p<0.00001], and NYHA functional class [MD: -0.58, 95% CI: -0.80 to --0.35; p<0.00001]. However, there was no significant difference in HF hospitalization between HPSP and BiVP. LBBP as modality of HPSP demonstrated superior outcomes in achieving electrical ventricular synchrony and systolic function, as well as alleviating HF symptoms, compared to other pacing techniques.

Impact of Neonatal Intervention on Left Ventricular Performance in Ebstein’s Anomaly and Tricuspid Valve Dysplasia

Severe neonatal Ebstein's anomaly (EA) and tricuspid valve dysplasia (TVD) are associated with high perinatal morbidity and mortality. The authors recently demonstrated left ventricular (LV) dysfunction and dyssynchrony to be prevalent in affected newborns and to contribute to poor outcomes. The aim of this study was to investigate the impact of patent ductus arteriosus (PDA) closure, spontaneous or surgical ligation, or right ventricular exclusion (Starnes procedure) on LV performance in neonatal EA and TVD. Neonates with EA or TVD encountered from 2004 to 2018 at three institutions were identified. Pre-and postoperative LV function was assessed using two-dimensional, Doppler-derived deformation (six-segment vector velocity imaging) and two measures of mechanical dyssynchrony (the SD of time to peak and global dyssynchrony index), and values were compared using paired t test analysis or the Wilcoxon rank sum test. Before the intervention, LV function was impaired in the PDA (n=18) and Starnes (n=6) groups and was similar between groups. After PDA closure, LV performance did not change. After the Starnes procedure, however, LV function, including synchrony, improved significantly: fractional area change from 45±5% to 58±8% (P=.003), global circumferential strain from -18.2±5.0% to -32.5±5.5% (P=.01), cardiac index from 1.9±0.3 to 3.9±1.5L/min/m2 (P=.05), and circumferential strain dyssynchrony (dyssynchrony index from 0.19±0.09 to 0.04±0.02 [P=.009] and SD of time to peak from 59.8±18.5 to 29.9±8.2 [P=.02]). The Starnes procedure results in early improvements in LV dysfunction and dyssynchrony, not observed after PDA closure in neonatal severe EA and TVD, which may benefit critically unwell neonates.

Cardiac Magnetic Resonance Identifies Responders to Cardiac Resynchronization Therapy with an Assessment of Septal Scar and Left Ventricular Dyssynchrony.

Background: The response to cardiac resynchronization therapy (CRT) depends on septal viability and correction of abnormal septal motion. This study investigates if cardiac magnetic resonance (CMR) as a single modality can identify CRT responders with combined imaging of pathological septal motion (septal flash) and septal scar. Methods: In a prospective, multicenter, observational study of 136 CRT recipients, septal scar was assessed using late gadolinium enhancement (LGE) (n = 127) and septal flash visually from cine CMR sequences. The primary endpoint was CRT response, defined as ≥15% reduction in LV end-systolic volume with echocardiography after 6 months. The secondary endpoint was heart transplantation or death of any cause assessed after 39 ± 13 months. Results: Septal scar and septal flash were independent predictors of CRT response in multivariable analysis (both p < 0.001), while QRS duration and morphology were not. The combined approach of septal scar and septal flash predicted CRT response with an area under the curve of 0.86 (95% confidence interval (CI): 0.78-0.94) and was a strong predictor of long-term survival without heart transplantation (hazard ratio 0.27, 95% CI: 0.10-0.79). The accuracy of the approach was similar in the subgroup with intermediate (130-150 ms) QRS duration. The combined approach was superior to septal scar and septal flash alone (p < 0.01). Conclusions: The combined assessment of septal scar and septal flash using CMR as a single-image modality identifies CRT responders with high accuracy and predicts long-term survival.

Blood volume contributes to the mechanical synchrony of the myocardium during moderate and high intensity exercise in women.

Whether blood volume (BV) primarily determines the synchronous nature of the myocardium remains unknown. This study determined the impact of standard blood withdrawal on left ventricular mechanical dyssynchrony (LVMD) in women. Transthoracic speckle-tracking echocardiography and central hemodynamic measurements were performed at rest and during moderate- to high-intensity exercise in healthy women (n = 24, age = 53.6 ± 16.3year). LVMD was determined via the time to peak standard deviation (TPSD) of longitudinal and transverse strain and strain rates (LSR, TSR). Measurements were repeated within a week period immediately after a 10% reduction of BV. With intact BV, all individuals presented cardiac structure and function variables within normative values of the study population. Blood withdrawal decreased BV (5.3 ± 0.7 L) by 0.5 ± 0.1L. Resting left ventricular (LV) end-diastolic volume (-8%, P = 0.040) and passive filling (-16%, P = 0.001) were reduced after blood withdrawal. No effect of blood withdrawal was observed for any measure of LVMD at rest (P ≥ 0.225). During exercise at a fixed submaximal workload (100W), LVMD of myocardial longitudinal strain (LS TPSD) was increased after blood withdrawal (36%, P = 0.047). At peak effort, blood withdrawal led to increased LVMD of myocardial transverse strain rate (TSR TPSD) (31%, P = 0.002). The effect of blood withdrawal on TSR TPSD at peak effort was associated with LV concentric remodeling (r = 0.59, P = 0.003). Marked impairments in the mechanical synchrony of the myocardium are elicited by moderate blood withdrawal in healthy women during moderate and high intensity exercise.

A preliminary study on the standard value of left ventricular mechanic dyssynchrony by speckle tracking

Abstract Background Speckle tracking imaging automatic functional imaging (AFI) is a new method to measure left ventricular mechanical dyssynchrony. Parameter peak strain dispersion (PSD) is the standard deviation when the long axial strain of 17 segments of the left ventricle (LV) reach there’s peak. There is no unified standard value at present. Li C[1] included 59 healthy women aged 43.08 ± 8.22 years old, whose PSD was 31.44±3.83ms. Ji X[2] included 57 healthy volunteers aged 43.30 ±6.03 years old whose PSD value was 23.8±2.2ms. Some studies referred to the standard range of Yu index and used PSD&amp;gt;32.6ms as an indicator of left ventricular mechanic dyssynchrony. Purpose To investigate the standard value range of PSD and PSD/R-R interval. Methods Healthy volunteers who came to our hospital for physical examination from March 2020 to September 2021 were included, excluding hypertension, diabetes, hyperlipidemia, coronary heart disease and other diseases. According to the 20∼29 years old, 30∼39 years old, 40∼49 years old, 50∼59 years old, 60∼69 years old and 70∼79 years old, 10 males and 10 females were included, respectively. GE Vivid E95 was used to collect echocardiographic images, and the following parameters were measured: ①The general parameters of the heart, such as the diameter of the atrium(LA) and the left ventricle (LV) and the thickness of the left ventricular wall .; ②the values of PSD and PSD/ R-R interval. The normal distribution parameters were represented by mean plus or minus the standard deviation. Analysis of variance and post hoc test (LSDt-test) were used to analyse measured values statistically. Results Values of general echocardiographic data such as BSA, atrial and ventricular diameter, interventricular septal thickness, left ventricular posterior wall thickness, and LV ejection fraction were consistent with the guideline of Recommendations for Cardiac Chamber Quantification by Echocardiography in Adults: An Update from the American Society of Echocardiography and the European Association of Cardiovascular Imaging published in 2015. The range of PSD values for subjects in this study was 43±9ms, and the maximum was 65ms. The range of PSD/R-R was 5±1%, and the maximum was 7%. The values of PSD and PSD/R-R were 36±5ms(27∼45ms) and 4.4±0.76%(3∼6.4%) for 20∼39 years old, 42±5ms(34.9-54ms), 5.0±0.8%(3.5-6.7%) in 40∼59 years; 51±8ms(34∼65ms), 5.8±0.9%(3.9∼7%) in age 60∼79. Conclusions The preliminary study has shown that left ventricular mechanical dyssynchrony is associated with age. The standard value range of PSD is inconsistent in different age groups, and PSD and PSD/R-R values increase with age.PSD values at different agesBar chart of PSD values at different age

Clustering by artificial intelligence for multi-vessel coronary artery disease on electrocardiography gated single photon emission computed tomography

Abstract Backgrounds Diagnosis of multi-vessel coronary artery disease (MVD) on single photon emission computed tomography (SPECT) is recognized to be difficult. We tried to classify patients who were suspected coronary artery stenosis by artificial intelligence (AI) clustering on parameters of electrocardiogram (ECG) gated SPECT (gated-SPECT), and evaluated their predictive value for MVD. Methods We enrolled consecutive 335 patients (median:74years [68, 79], 255man) who underwent adenosine stress ECG gated-SPECT and coronary angiography in 3-months. No sinus rhythm patients were excluded. MVD was defined as at least two main branch coronary artery stenosis whose fractional flow reserve over 0.80 which was evaluated by coronary angiography. Univariate logistic regression analysis extracted significant predictors among many paremeters of the SPECT (summed score, left ventricular (LV) volume, systolic and diastolic function, and degree of LV dyssynchrony), and using them, AI clustering (K-means) was performed. Results Breakdown of MVD was as follows: MVD was 48 (double vessel disease 30, LMT stenosis 5, and triple vessel 13). Single vessel disease was 91, and no lesion was 196 cases. Clustering was performed using 21 significant parameters of the SPECT and clinical characteristics (Diabetes, LVEF, heart rate(HR), SD-TES, MDSV, 1/3 mean filling rate, peak filling ratio on adenosine stress, LVEF, HR, SD-TES, MDSV at rest, and other 10 predictors). Number of clusters was set as 4 by elbow plotting method. Prevalence of MVD was significantly different in the 4 clusters (Odds ratio: Cluster B/C/D to A, 3.05/3.61/6.60, respectively). Compared with cluster A, clusteter B/C/D showed increased summed stress score, chronic kidney disease, SD-TES (=left ventricular end-systolic dyssynchrony parameter) on stress, decreased left ventricular ejection fraction and 1/3 mean filling rate. Conclusions AI clustering on gated-SPECT had powerful predictive value for MVD.

Predictors of clinical outcome in adults with repaired tetralogy of Fallot and the prognostic value of surrogate markers of right ventricular dyssynchrony

Abstract Introduction Sequelae or residual lesions after surgical repair of tetralogy of Fallot (rTOF) are inevitable and have an impact on long-term outcome. So far, most of our attention was directed to negative consequences of residual pulmonary regurgitation. Less attention has been paid to the impact of right bundle branch block and intraventricular dyssynchrony on biventricular function, exercise capacity and clinical outcome. Purpose Using the Swiss Adult Congenital HEart disease Registry we aimed to investigate the 5-year clinical course of adults with rTOF late after surgical repair. We used echocardiography strain analysis as surrogate to quantify right and left ventricular dyssynchrony and correlated our findings with routine clinical measures from cardiopulmonary exercise testing, neurohumoral blood work and cardiac magnetic resonance imaging with the aim to identify patients at increased risk for an adverse clinical event. Methods 2D speckle-tracking strain analysis of the right and left ventricle was performed with dedicated software (Tomtec, Germany). RV dyssynchrony index was measured as the standard deviation of time to peak shortening (TTP) in six RV segments. Interventricular shortening delay (IVSD) was defined as the maximal delay of TTP between ventricular segments. We constructed a multivariate model with NT-proBNP, ECG, clinical, imaging and exercise testing variables to predict the composite outcome of all-cause mortality, relevant arrhythmias and hospital admission for decompensated heart failure. Results A total of 285 patients were included. During a mean follow-up of 48±21 months, 33 patient (12 %) suffered an adverse event with a mean time to event of 30 ± 21 months after the baseline visit. RV dyssynchrony index and IVSD did not differ statistically between the groups with and without events (49±31ms vs 41±18ms, p-value 0.21, 130±65ms vs. 103±50ms, p-value 0.9). In the multivariate Cox-regression model, NT-proBNP, right atrial area and peak heart rate at exercise testing were independent predictors of outcome. An integrated risk score with the median values of these 3 variables as cut-off was highly accurate in separating patients at low risk (score 0; n=39) and high risk (score 3; n=38) for an adverse event. After 6 years of follow-up, no patient at low risk (score 0) had an adverse event, while in 62% of patients at high risk (score 3) an adverse event occurred (p&amp;lt;0.001). Conclusion In our cohort of rTOF patients, echocardiographic surrogates of RV dyssynchrony did not correlate with clinical events. An integrated multimodality approach proved to be effective in predicting outcomes.

Acute deterioration in dyssynchrony and systolic function from Lot-CRT to LBBB pacing

Abstract Background Better electrical synchronization and left ventricular (LV) systolic function was recently reported in left bundle branch–optimized cardiac resynchronization therapy ( Lot-CRT ) when compared with conventional CRT. The implantation of left bundle branch pacing (LBBP) is less expensive, easier to operate and has shorter exposure time to X-ray than Lot-CRT. Purpose To observe whether there are negative changes in dyssynchrony and LV systolic function when switched from Lot-CRT to LBBP. determine whether LBBP pacing alone can replace CRT therapy. Methods 30 patients (21 males, 64.4±9.5 years, 43% with persistent atrial fibrillation) who fulfilled the criteria of CRT implantation received Lot-CRT. The right atrial electrode of the patients with atrial fibrillation or the right ventricular electrode of those with sinus rhythm was implanted into the left bundle branch area. After six months, 20 patients whose LV ejection fraction (LVEF) increased by more than 5% and New York Heart Association functional class increased by at least 1 grade were selected for further investigation. Right and left ventricular pacemaker electrodes were programmed to shut off, leaving only the left bundle branch area pacing for one month. The LV size, systolic function, interventricular mechanical delay (IVMD), and LV mechanical dyssynchrony (LVMD) were compared by using two-dimensional speckle tracking echocardiography. Results It was found that QRS duration slightly widened, the LA size increased, the LV size slightly increased and LVEF decreased, p&amp;lt;0.05. There was no statistical significance in the IVMD (p=0.064). The LV mechanical dyssynchrony increased significantly, p&amp;lt;0.001. Conclusions Deteriotation of LV dyssynchrony and systolic function was recorded when Lot-CRT to LBBP for a short period in recovering patients with systolic dysfunction. It indicates that LBBP may not yet maintain the benefits of Lot-CRT in this group of patients.The comparison between Lot-CRT and LBBP

Abstract 17657: The Effect of Medical Therapy on Reducing the Risk of Pacing Induced Cardiomyopathy

Introduction: Right ventricular (RV) pacing results in left ventricular dyssynchrony that can lead to pacing induced cardiomyopathy (PICM). The risk of PICM increases with RV pacing burden. No prior trials have investigated the effect of medical therapy on preventing PICM in patients with high RV pacing burden. The goal of this study was to investigate whether ACE inhibitors (ACEI), angiotensin receptor blockers (ARB), and beta blockers (BB) reduce the risk of PICM in patients with high RV pacing burden. Methods: This was a retrospective study which included patients with normal ejection fraction (EF) and complete heart block who underwent single- or dual-chamber pacemaker placement at Wake Forest Baptist Medical Center between 1992 - 2013. Exclusion criteria were age &lt;18 and myocardial infarction. The medical therapy group included patients who received ACEI/ARB, BB, or both. The control group included patients who received neither ACEI/ARB nor BB. The primary endpoint was PICM, which was defined as upgrade to a biventricular device or reduction in EF by ≥10% without another etiology identified. Follow-up was 10 years or until development of PICM. Kaplan-Meier and multivariable Cox proportional hazards ratio survival analysis was performed. Results: The study included 642 patients. Average age was 71 ± 14. Females were 51%. ACEI/ARB only was prescribed for 80 (12%), BB only was prescribed for 55 (9%), and both were prescribed for 114 (18%). PICM occurred in 12 out of a total of 249 in the medical therapy group (4.8%) and 28 out of a total of 393 in the control group (7.1%). The risk of PICM was significantly lower in the medical therapy group compared to the control group (HR 0.34, 95% CI 0.16 - 0.71, P&lt;0.01) in a model fully adjusted for age, sex, hypertension, diabetes mellitus, chronic kidney disease, and atrial fibrillation. Conclusions: In patients who have high RV pacing burden, medical therapy with ACEI/ARB and BB appears to reduce the risk of PICM.

Left ventricular dyssynchrony measured by cardiovascular magnetic resonance-feature tracking in anterior ST-elevation myocardial infarction: relationship with microvascular occlusion myocardial damage.

Cardiovascular magnetic resonance-feature tracking (CMR-FT) enables quantification of myocardial deformation and may be used as an objective measure of myocardial involvement in ST-elevation myocardial infarction (STEMI). We sought to investigate the associations between myocardial dyssynchrony parameters and myocardium damage for STEMI. We analyzed 65 patients (45-80 years old) with anterior STEMI after primary percutaneous coronary intervention during 3-7 days [observational (STEMI) group] and 60 healthy volunteers [normal control (NC) group]. Myocardial dyssynchrony parameters were derived, including global and regional strain, radial rebound stretch and displacement, systolic septal time delay, and circumferential stretch. CMR characteristics, including morphologic parameters such as left ventricular ejection fraction (LVEF) (45.3% ± 8.2%) and myocardium damage in late gadolinium enhancement (LGE) (19.4% ± 4.7% LV), were assessed in the observation group. The global radial strain (GRS) and global longitudinal strain (GLS) substantially decreased in anterior STEMI compared with the NC group (GRS: 19.4% ± 5.1% vs. 24.8% ± 4.0%, P < 0.05; GLS: -10.1% ± 1.7% vs. -13.7% ± 1.0%, P < 0.05). Among 362 infarcted segments, radial and circumferential peak strains of the infarcted zone were the lowest (14.4% ± 3.2% and -10.7% ± 1.6%, respectively). The radial peak displacement of the infarct zone significantly decreased (2.6 ± 0.4 mm) (P < 0.001) and manifested in the circumferential displacement (3.5° ± 0.7°) in the STEMI group (P < 0.01). As microvascular occlusion (MVO) was additionally present, some strain parameters were significantly impaired in LGE+/MVO+ segments (radial strain [RS]: 12.2% ± 2.1%, circumferential strain [CS]: -9.6% ± 0.7%, longitudinal strain [LS]: -6.8% ± 1.0%) compared to LGE+/MVO- (RS: 14.6% ± 3.2%, CS: -10.8% ± 1.8%, LS: -9.2% ± 1.3%) (P < 0.05). When the extent of transmural myocardial infarction is greater than 75%, the parameter of the systolic septal delay (mean, 148 ms) was significantly reduced compared to fewer degrees of infarction (P < 0.01). In anterior STEMI, the infarcted septum swings in a bimodal mode, and myocardial injury reduces the radial strain contractility. A more than 75% transmural degree was the septal strain-contraction reserve cut-off point.

Comparison of the left ventricular dyssynchrony between stylet-driven and lumen-less lead technique in left bundle branch area pacing using myocardial perfusion scintigraphy.

Left bundle branch area pacing (LBBAP) has emerged as a novel physiological pacing method to reduce left ventricular (LV) dyssynchrony due to ventricular pacing. Only lumen-less pacing leads (LLLs) with fixed helixes could achieve LBBAP previously, but recently, LBBAP has been performed using stylet-driven leads (SDLs). This study aimed to evaluate the LV dyssynchrony between SDLs and LLLs techniques in LBBAP. We retrospectively evaluated patients who underwent LBBAP with either SDLs or LLLs. We compared both groups' electrocardiogram (ECG) findings and LV dyssynchrony parameters derived from myocardial perfusion scintigraphy. LV dyssynchrony parameters consisted of phase analysis and regional wall motion analysis. We evaluated bandwidth, phase standard deviation (PSD), and entropy in the phase analysis. The time to the end-systolic frame (TES) was calculated in regional wall motion analysis using single-photon emission computed tomography (SPECT). We also evaluated the maximum differences between segmental TES (MDTES), the standard deviation of TES (SDTES), and the difference in the TES between the lateral wall and septum (DTES-LS). In total, 97 patients were enrolled. The success rate of LBBAP did not differ between the groups [SDLs: 47/48 patients (98%) vs. LLLs: 47/51 patients (92%), P=0.36]. The paced QRS duration and the stimulus to the peak LV activation time (stim-LVAT) also did not differ between SDL and LLL groups (122±10 vs. 119±12 ms, P=0.206; 69±12 vs. 66±13 ms, P=0.31, respectively). There were no differences in bandwidth, PSD, and entropy between SDL and LLL groups (73°±37° vs. 86°±47°, P=0.18; 19°±8.5° vs. 21°±9.7°, P=0.19; 0.57±0.08 vs. 0.59±0.08, P=0.17, respectively). The regional wall motion analysis parameters MDTES, SDTES, and DTES-LS also did not differ between SDL and LLL groups (19%±10% vs. 20%±10%, P=0.885; 5.0%±2.5% vs. 5.0%±2.5%, P=0.995; 5.0%±3.7% vs. 4.8%±4.2%, P=0.78, respectively). LBBAP using SDLs was comparable to LV electrical and mechanical synchrony with LLLs.

Simultaneous assessment of left ventricular mechanical dyssynchrony using integrated 13N-ammonia PETMR system: direct comparison of PET phase analysis and MR feature tracking

BackgroundTo compare phase analysis with positron emission tomography (PA) and magnetic resonance feature tracking derived myocardial strain (FT) for left ventricular (LV) mechanical dyssynchrony using PETMR system in patients with ischemic heart disease. Methods and resultsPatients who underwent rest-pharmacological stress 13N ammonia PETMR were enrolled. Histogram bandwidth (BW) and phase standard deviation (PSD) were compared to global longitudinal, long axis radial, short axis circumferential, and radial strain (GLS, GRS, SA Circ, and SA Rad) obtained from FT. LV dyssynchrony index (SDI) derived from PA and FT were compared. BW and PSD showed significant correlations with FT (a Pearson’s coefficient r = 0.64, P < .0001, and r = 0.51, P < .0001 for SA Circ; r = 0.67, P < .0001, and r = 0.74, P < .0001 for GLS; r = − 0.60, P < .0001, r = − 0.61, P < .0001 for SA Rad; r = − 0.62, P < .0001, and r = − 0.68, P < .0001 for GRS, respectively). Bland-Altman plots for SDI showed a preferable agreement (95% limit of agreement − 0.12 to 0.075, − 0.20 to 0.098, − 0.38 to 0.077, and − 0.37 to 0.032; bias 0.0068 ± 0.056, 0.026 ± 0.068, 0.11 ± 0.088, and 0.13 ± 0.079 for SA Circ, SA Rad, GLS, and GRS, respectively). ConclusionIn simultaneous acquisition using PETMR, comparison of PET phase analysis and MR strain showed a good correlation.

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

ObjectivesMyocardial 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. MethodsThis 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. ResultsPSD 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 ≥ 35 pg/mL and chronic diabetic complications (P < .05). BNP ≥ 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). ConclusionsLVSD 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.