Left Ventricular Dyssynchrony Index Research Articles

Real-time assessment of LV synchrony in AV block population undergoing LBB pacing using ECG Imaging

Abstract Background Left bundle branch pacing (LBBP) may prevent right ventricular (RV) pacing-induced dyssynchrony (DYS). Nowadays, real-time assessment of DYS correction is indirectly measured with QRS narrowing. Non-invasive ECG imaging (ECGI) technique may provide an evaluation of electrical resynchronization based on quantitative assessment of ventricular local activation time (LAT) maps. Purpose To assess whether real-time ECGI could evaluate LV synchrony achieved through LBBP, in a consecutive AV block (AVB) population. Methods A cohort of 12 patients with AVB were included. ECGI was performed during the implant procedure. ECGI signals were computed using an artificial intelligence derived cardiac geometry model. Ventricular LAT maps were obtained when pacing from septal RV and with LBBP (lead placed according to guidelines ECG criteria) for each of the patients. The following parameters were obtained from ECGI LAT maps to assess intra and interventricular DYS pacing at the RV septal and LBB locations: total activation time (TAT), left ventricular activation time (LVAT), left ventricular dyssynchrony index (LVDI), ventricular electrical uncoupling (VEU = mean LVAT – mean RV activation time) and histogram overlap between LV and RV activation times distribution. RESULTS: Nine of the 12 patients were men (75%), with a median age of 79[Q1 75-Q3 82]. QRS duration during RV septal pacing was 150 ms [138-172]. Median LVEF was 47% [26-59]. In Figure 1, it can be observed that dyssynchrony variables are corrected across all patients when reaching LBBP. Figure 2 shows activation maps during RV septal pacing and during LBBP, along with the QRS duration, and the RV and LV histogram of activation times. Conclusion ECGI is useful for assessing the LV synchrony correction during LBBP in an AV block population.Dyssynchrony variablesActivation maps with QRS and histograms

ECG imaging as a real time tool to guide left bundle branch pacing implant in patients with left bundle branch block and resynchronization therapy indication

Abstract Background Left bundle branch pacing (LBBP) has emerged as a promising alternative technique for cardiac resynchronization therapy (CRT). ECG imaging (ECGI) may provide an accurate assessment of electrical resynchronization using real-time maps during LBBP implant. Purpose To evaluate the usefulness of ECGI to guide LBBP implant, by analyzing the ventricular activation times and the degree of resynchronization at each screwing step during the lead implant. Methods Four patients with CRT indication and left bundle branch block (LBBB) referred for LBBP were prospectively enrolled. ECGI was performed during the implant procedure. Cardiac signals were recorded using ECGI and projected into an artificial intelligence-derived geometric model. Thus, generating imageless and non-invasive activation maps at defined stages during lead screwing: basal rhythm (LBBB), right ventricular (RV) septum, mid-septal, deep-septal, and finally pacing from the left bundle branch (according with guidelines ECG criteria). The following parameters were measured: a) total activation time (TAT); b) left ventricular activation time (LVAT); c) left ventricular dyssynchrony index (LVDI) (as a quantifier of intraventricular dyssynchrony); d) ventricular electrical uncoupling (VEU); and e) histogram overlap between LV and RV distribution (the last 2 markers of interventricular dyssynchrony). Results The study cohort comprised men with a median age of 68 [Q1 59- Q3 79], with a median basal LBBB QRS duration of 175 ms [160-188] and a median LVEF of 32% [28-39]. A shortening of the activation times and a decrease in intra and interventricular dyssynchrony was achieved when the final lead position was reached. See the results in Figure 2. Conclusion Real-time and imageless ECGI system may offer a novel approach for guiding LBBP and it is useful to ensure left ventricular resynchronization.ECGI to guide LBBP implantActivation and dyssynchrony measurements

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.

Biventricular endocardial pacing and left bundle branch area pacing for cardiac resynchronization: Mechanistic insights from electrocardiographic imaging, acute hemodynamic response, and magnetic resonance imaging

Biventricular endocardial pacing (BiV-endo) has demonstrated superior cardiac resynchronization compared to conventional biventricular epicardial pacing (BiV-epi). Left bundle branch area pacing (LBBAP) may also achieve effective cardiac resynchronization therapy (CRT). The purpose of this study was to compare the acute electrical and hemodynamic effects of BiV-epi, BiV-endo, and LBBAP delivered from the LV endocardium and to assess how myocardial scar affects response. Eleven patients with heart failure and indications for CRT underwent a temporary pacing study with electrocardiographic imaging (ECGi) and hemodynamic assessment. BiV-endo was delivered by stimulation of the left ventricular (LV) lateral wall, and LBBAP was delivered by stimulation of the LV septum, at the site of a Purkinje potential. LV activation time (LVAT-95), LV dyssynchrony index (LVDI), biventricular activation time (BIVAT-90), and biventricular dyssynchrony index (BIVDI) were calculated. Myocardial scar was assessed using magnetic resonance imaging (MRI). The protocol was completed in 10 patients. Compared to BiV-epi (LVAT-95: 79.2 ± 13.1 ms; LVDI: 26.6 ± 3.4 ms) LV resynchronization was superior during BiV-endo (LVAT-95: 48.5 ± 14.9 ms; P = .001; LVDI: 16.6 ± 6.4 ms; P = .002) and LBBAP (LVAT-95: 48.9 ± 12.5 ms; P = .001; LVDI: 15.3 ± 3.4 ms; P = .001). Biventricular resynchronization was similarly superior during BiV-endo and LBBAP vs BiV-epi (BIVAT-90 and BIVDI; P <.05). The rate of acute hemodynamic responders was higher during BiV-endo (90%) and LBBAP (70%) vs BiV-epi (50%). The benefits of LBBAP (but not BiV-endo) on LV resynchronization were attenuated when septal scar was present in a subset of 8 patients who underwent MRI. Our findings suggest superior electrical resynchronization and a higher proportion of acute hemodynamic responders during BiV-endo and LBBAP compared to BiV-epi. Electrical resynchronization was similar between BiV-endo and LBBAP; however, septal scar seemed to attenuate response to LBBAP.

Comparison between his-bundle pacing and biventricular pacing as cardiac resynchronization therapy for heart failure patients: a systematic review and meta-analysis

Abstract Funding Acknowledgements Type of funding sources: None. Background Cardiac resynchronization therapy (CRT) has demonstrated significant improvements in cardiovascular outcomes of selected heart failure patients. However, conventional biventricular CRT implantation can be challenging due to unfavorable coronary sinus anatomy, leads to lead instability, poor capture, and insufficient cardiac resynchronization. His-bundle pacing has gained interest as alternative strategy for patients underwent biventricular CRT implantation when coronary sinus lead implantation is unsuccesful or in non-responder cases. Purpose This study aims to compare the efficacy of his-bundle pacing and biventricular pacing in improving electrocardiographic, echocardiographic, and clinical parameters of heart failure patients that required resynchronization therapy. Methods A search for eligible studies was conducted until August 2021 on three databases (PubMed, ScienceDirect, ProQuest). Included studies were evaluated for risk of bias. Our primary outcomes of interest were mean difference in QRS duration, left ventricular ejection fraction (LVEF), and change in systolic blood pressure (SBP). We also investigated left ventricular activation time, left ventricular dyssynchrony index, left ventricular end-systolic volume (LVESV), New York Heart Association (NYHA) functional class, 6-minute walk test, quality of life, heart failure hospitalization and cardiovascular or all cause death. Review Manager (RevMan) 5.4 was utilized to compute mean differences. Results We identified five studies from 2010 to 2019, involving 95 heart failure patients underwent CRT implantation. Pooled analysis showed that his-bundle pacing resulted in significant narrowing of QRS duration compared to biventricular pacing [Mean Difference -23.17 ms (95% CI -36.10, -10.24; p=0.0004; I2=0.63)]. Left ventricular activation time and left ventricular dyssynchrony index were significantly improved in his bundle pacing. There were no significant differences of changes in LVEF, LVESV, and SBP. Clinical parameters such as NYHA functional class, 6-minute walk test, and quality of life were significantly improved in both pacing modality. No significant difference in heart failure hospitalization and cardiovascular or all cause mortality. Conclusion His-bundle pacing delivers better decrease of QRS duration, also reduction in left ventricular activation time and left ventricular dyssynchrony index compared to biventricular pacing. These suggests that his-bundle pacing is a reasonable alternative option for cardiac resynchronization therapy.

Abstract 11633: Three-Dimensional Speckle-Tracking Echocardiographic Assessment of Ventricular Dyssynchrony and Arrhythmic Risk in Mitral Valve Prolapse

Introduction: Dyssynchrony indices based on two-dimensional speckle tracking echocardiography have demonstrated added value in identifying patients with mitral valve prolapse (MVP) with a higher prevalence of arrhythmic complications and the potential for sudden cardiac death, but measurements are restricted to a single plane, and complex left ventricular (LV) dyssynchrony patterns may be overlooked. Hypothesis: The purpose of this study was to investigate whether three-dimensional speckle-tracking echocardiography helps in detecting MVP at higher arrhythmic risk. Methods: We studied 21 arrhythmic MVP patients (group 1) with a history of complex ventricular ectopy on holter and/or event monitor (n=17) or defibrillator implant (n=2), 21 MVPs with no arrhythmic complications (group 2) and 21 healthy controls (group 3). 3D LV longitudinal strain (3DE-LVLS) and area strain (3DE-LVAS) were determined (17 segments). 3D LV dyssynchrony index (3DE-LVDI) was obtained as the standard deviation of the times to peak area strain in 17 segments, normalized to RR interval. Results: MVP patients had significantly higher LV dyssynchrony index compared to controls (9.4±3.9% vs 4.3±2.5%, p=0.002) although they had similar LV ejection fraction (64% vs 61%, p=0.51). Group 1 and group 2 had similar LV ejection fraction and clinical data (p&gt;0.05). Bileaflet prolapse was more frequent in group 1 pts (52% vs 24%, p=0.03). Moderate mitral regurgitation was present in 9/21 group 1 pts and 3/21 group 2 pts (p=0.04). Group 1 pts had greater LV dyssynchrony index when compared with group 2 (10.7±4.1% vs 5.1±2.9%, p=0.0001). By ROC (receiver operating characteristics) curves, 3DE-LVDI and 3DE-LVAS cutoff values of 10.2% and -23.8%, respectively, had 89% and 85% sensitivity and 79% and 76% specificity in identifying the presence of significant arrhythmias with areas under the curve 0.87 and 0.84. Conclusions: Impairment of LV deformation parameters determined by three-dimensional speckle tracking echocardiography may help detect increased arrhythmic risk in patients with MVP.

Cardiovascular Imaging Applications in Clinical Management of Patients Treated with Cardiac Resynchronization Therapy

Cardiovascular imaging techniques, including echocardiography, nuclear cardiology, multi-slice computed tomography, and cardiac magnetic resonance, have wide applications in cardiac resynchronization therapy (CRT). Our aim was to provide an update of cardiovascular imaging applications before, during, and after implantation of a CRT device. Before CRT implantation, cardiovascular imaging techniques may integrate current clinical and electrocardiographic selection criteria in the identification of patients who may most likely benefit from CRT. Assessment of myocardial viability by ultrasound, nuclear cardiology, or cardiac magnetic resonance may guide optimal left ventricular (LV) lead positioning and help to predict LV function improvement by CRT. During implantation, echocardiographic techniques may guide in the identification of the best site of LV pacing. After CRT implantation, cardiovascular imaging plays an important role in the assessment of CRT response, which can be defined according to LV reverse remodeling, function and dyssynchrony indices. Furthermore, imaging techniques may be used for CRT programming optimization during follow-up, especially in patients who turn out to be non-responders. However, in the clinical settings, the use of proposed functional indices for different imaging techniques is still debated, due to their suboptimal feasibility and reproducibility. Moreover, identifying CRT responders before implantation and turning non-responders into responders at follow-up remain challenging issues.

Novel measures of left ventricular electromechanical discoordination predict clinical outcomes in children with pulmonary arterial hypertension.

Adverse ventricle-ventricle interaction and resultant left ventricular (LV) dysfunction are a recognized pathophysiological component of disease progression in pulmonary arterial hypertension (PAH) and can be associated with electrical and mechanical dyssynchrony. The purpose of this study was to investigate the clinical and mechanistic implications of LV electromechanical dyssynchrony in children with PAH by using novel systolic stretch and diastolic relaxation discoordination indexes derived noninvasively from cardiac MRI (CMR). In children with PAH referred for CMR (n = 64) and healthy controls (n = 20), we calculated two novel markers of ventricular discoordination, systolic stretch fraction (SSF) and diastolic relaxation fraction (DRF). SSF and DRF were evaluated with respect to 1) electrical dyssynchrony, 2) functional status, and 3) composite clinical outcomes. SSF was increased in patients with PAH compared with controls (P = 0.004). There was no difference in DRF between PAH and control groups. There were no differences between groups in standard mechanical dyssynchrony and LV global circumferential strain. Increased SSF was associated with greater electrical dyssynchrony (QRS duration) as well as worse WHO functional class. SSF, DRF, mechanical dyssynchrony, and right ventricular (RV) volumes were prognostic for worse clinical outcomes. LV dyssynchrony indexes are altered in pediatric patients with PAH compared with controls in proportion with greater degrees of RV dilation. Patients with PAH with greater dyssynchrony have worse clinical outcomes. RV-induced increased LV electromechanical dyssynchrony therefore may be an important link in the causal pathway from PAH to clinically significant LV dysfunction. Since dyssynchrony could precede overt LV dysfunction, addition of ventricular synchrony analysis to CMR postprocessing protocols may be of clinical benefit.NEW & NOTEWORTHY We demonstrate that left ventricular discoordination indexes are altered in pediatric patients with pulmonary arterial hypertension compared with controls and pediatric patients with pulmonary arterial hypertension with greater dyssynchrony have worse clinical outcomes. Furthermore, there is evidence for the mechanism of right ventricular-induced left ventricular discoordination to include a combination of delayed early systolic electromechanical activation, late-systolic septal shift, and prolonged, postsystolic septal thickening.

Reproducibility of Left Ventricular Dyssynchrony Indices by Three-Dimensional Speckle-Tracking Echocardiography: The Impact of Sub-optimal Image Quality.

Background: 3D speckle-tracking echocardiography (3D-STE) is a novel method to quantify left ventricular (LV) mechanical dyssynchrony. 3D-STE is influenced by image quality, but studies on the magnitude of its effect on 3D-STE derived LV systolic dyssynchrony indices (SDIs) and their test-retest reproducibility are limited.Methods: 3D-STE was performed in two groups, each comprising 18 healthy volunteers with good echocardiographic windows. In study 1, optimal and inferior-quality images, by intentionally poor echocardiographic technique, were acquired. In study 2, sub-optimal quality images were acquired by impairing ultrasound propagation using neoprene rubber sheets (thickness 2, 3, and 4 mm) mimicking mildly, moderately, and severely impaired images, respectively. Measures (normalized to cardiac cycle duration) were volume- and strain-based SDIs defined as the standard deviation of time to minimum segmental values, and volume- and strain-derived dispersion indices. For both studies test-retest reproducibility was assessed.Results: Test-retest reproducibility was better for most indices when restricting the analysis to good quality images; nevertheless, only volume-, circumferential strain-, and principal tangential strain-derived LV dyssynchrony indices achieved fair to good reliability. There was no evidence of systematic bias due to sub-optimal quality image. Volume-, circumferential strain-, and principal tangential strain-derived SDIs correlated closely. Radial strain- and longitudinal strain-SDI correlated moderately or weakly with volume-SDI, respectively.Conclusions: Sub-optimal image quality compromised the reliability of 3D-STE derived dyssynchrony indices but did not introduce systematic bias in healthy individuals. Even with optimal quality images, only 3D-STE indices based on volume, circumferential strain and principal tangential strain showed acceptable test-retest reliability.

The early alteration of left ventricular strain and dys-synchrony index in breast cancer patients undergoing anthracycline therapy using layer-specific strain analysis.

The primary aim of this study was to evaluate early changes in cardiac function after anthracycline therapy with layer-specific speckle-tracking echocardiography (STE) and mechanical dys-synchrony. A total of 78 breast cancer patients (ranging 31~72years) exposed to anthracycline treatment were recruited in this study. All patients received both conventional two-dimensional speckle-tracking echocardiographs at baseline, as well as after the completion of 2 and 4 cycles of the regimen. Layer-specific longitudinal strain (LS) and circumferential strain (CS) of the 3 myocardial layers (endocardium, mid-myocardium, and epicardium) were automatically measured. Peak systolic dispersion (PSD) was defined as the standard deviation of the time to peak strain of the 18 segments, divided by the RR interval. There were no significant differences in conventional echocardiographic parameters during treatment (all P>.05). Peak endocardium CS at basal level decreased significantly after 2 and 4 cycles compared with baseline (both P=.001), while PSD significantly increased in that same period versus baseline (both P=.000). Endocardium and mid-myocardium LS, peak mid-myocardium and epicardium CS at the basal level, peak CS of all three layers at the papillary level, and peak endocardium and mid-myocardium CS at the apical level all significantly decreased after 4 cycles, compared with baseline and 2 cycles (all P=.000). This study showed that myocardial deformation impairment occurred as early as 2 cycles after anthracycline chemotherapy. Endocardium CS at the basal level and left ventricular dys-synchrony index PSD were the initial cardiac abnormalities in anthracycline-treated breast cancer patients.

Prognostic value of left ventricular dyssynchrony evaluated by gated myocardial perfusion imaging in patients with chronic kidney disease and normal perfusion defect scores

BackgroundThis study aimed to investigate whether indices of left ventricular (LV) dyssynchrony by gated myocardial perfusion SPECT (GMPS) could be useful to predict prognosis in chronic kidney disease (CKD) patients with normal perfusion defect scores. MethodsOne hundred and sixty-seven CKD patients with normal perfusion defect scores on adenosine-stress 201Tl GMPS and no previous history of overt heart diseases were enrolled. Phase standard deviation (PSD) and bandwidth (BW) were automatically calculated from GMPS. The major adverse cardiac events (MACEs) for a mean of 560 days were defined as sudden cardiac death, fatal arrhythmias, and acute coronary syndrome requiring urgent coronary revascularization. Patients were divided into two groups according to the presence or absence of MACEs. ResultsThe MACEs occurred in 12 patients (7.1%). Patients who experienced MACEs showed significantly higher PSD and wider BW than those who did not. In the Kaplan-Meier event-free survival analysis, cardiac event rate was significantly higher in the high-PSD and wide-BW group (n = 81) than in the low-PSD and narrow-BW group (n = 71) (P = .002). The multivariate regression analysis revealed that the PSD was associated with MACEs (odds ratio 1.33, 95% confidence interval 1.05-1.69, P = .01). ConclusionThe LV dyssynchrony indices from GMPS may be novel prognostic predictors in CKD patients with normal perfusion defect scores.

His Resynchronization Versus Biventricular Pacing in Patients With Heart Failure and Left Bundle Branch Block

BackgroundHis bundle pacing is a new method for delivering cardiac resynchronization therapy (CRT). ObjectivesThe authors performed a head-to-head, high-precision, acute crossover comparison between His bundle pacing and conventional biventricular CRT, measuring effects on ventricular activation and acute hemodynamic function. MethodsPatients with heart failure and left bundle branch block referred for conventional biventricular CRT were recruited. Using noninvasive epicardial electrocardiographic imaging, the authors identified patients in whom His bundle pacing shortened left ventricular activation time. In these patients, the authors compared the hemodynamic effects of His bundle pacing against biventricular pacing using a high-multiple repeated alternation protocol to minimize the effect of noise, as well as comparing effects on ventricular activation. ResultsIn 18 of 23 patients, left ventricular activation time was significantly shortened by His bundle pacing. Seventeen patients had a complete electromechanical dataset. In them, His bundle pacing was more effective at delivering ventricular resynchronization than biventricular pacing: greater reduction in QRS duration (−18.6 ms; 95% confidence interval [CI]: −31.6 to −5.7 ms; p = 0.007), left ventricular activation time (−26 ms; 95% CI: −41 to −21 ms; p = 0.002), and left ventricular dyssynchrony index (−11.2 ms; 95% CI: −16.8 to −5.6 ms; p < 0.001). His bundle pacing also produced a greater acute hemodynamic response (4.6 mm Hg; 95% CI: 0.2 to 9.1 mm Hg; p = 0.04). The incremental activation time reduction with His bundle pacing over biventricular pacing correlated with the incremental hemodynamic improvement with His bundle pacing over biventricular pacing (R = 0.70; p = 0.04). ConclusionsHis resynchronization delivers better ventricular resynchronization, and greater improvement in hemodynamic parameters, than biventricular pacing.

Impact of the cone operation on left ventricular size, function, and dyssynchrony in Ebstein anomaly: a cardiovascular magnetic resonance study

BackgroundIn addition to tricuspid regurgitation (TR) and right ventricular (RV) enlargement, patients with Ebstein anomaly are at risk for left ventricular (LV) dysfunction and dyssynchrony. We studied the impact of the cone tricuspid valve reconstruction operation on LV size, function, and dyssynchrony.MethodsAll Ebstein anomaly patients who had both pre- and postoperative cardiovascular magnetic resonance (CMR) studies were retrospectively identified. From cine images, RV and LV volumes and ejection fractions (EF) were calculated, and LV circumferential and longitudinal strain were measured by feature tracking. To quantify LV dyssynchrony, temporal offsets (TOs) were computed among segmental circumferential strain versus time curves using cross-correlation analysis and patient-specific reference curves. An LV dyssynchrony index was calculated as the standard deviation of the TOs.ResultsTwenty patients (65% female) were included with a median age at cone operation of 16 years, and a median time between pre- and postoperative CMR of 2.8 years. Postoperatively, there was a decline in the TR fraction (56 ± 19% vs. 5 ± 4%, p < 0.001), RV end-diastolic volume (EDV) (242 ± 110 ml/m2 vs. 137 ± 82 ml/m2, p < 0.001), and RV stroke volume (SV) (101 ± 35 vs. 51 ± 7 ml/m2, p < 0.001). RV EF was unchanged. Conversely, there was an increase in both LV EDV (68 ± 13 vs. 85 ± 13 ml/m2, p < 0.001) and LV stroke volume (37 ± 8 vs. 48 ± 6 ml/m2, p < 0.001). There was no change in LV EF, or global circumferential and longitudinal strain but basal septal circumferential strain improved (16 ± 7% vs. 22 ± 5%, p = 0.04). LV contraction become more synchronous (dyssynchrony index: 32 ± 17 vs. 21 ± 9 msec, p = 0.02), and the extent correlated with the reduction in RV EDV and TR.ConclusionsIn patients with the Ebstein anomaly, the cone operation led to reduced TR and RV stroke volume, increased LV stroke volume, improved LV basal septal strain, and improved LV synchrony. Our data demonstrates that the detrimental effect of the RV on LV function can be mitigated by the cone operation.

Assessment of Left Ventricular Dyssynchrony using Gated Myocardial Perfusion SPECT in Cardiac Resynchronization Therapy

In cardiac resynchronization therapy (CRT), even if patient selection is made according to Japanese adaptive criteria, there are non-responders. Its main factor is considered to be the lack of adequate preoperative assessment against mechanical left ventricular dyssynchrony. Recently, phase analysis was enabled on gated myocardial perfusion SPECT (GMPS). The purpose of this study was to examine the relationship between the index of phase analysis using the two software (cardioREPO® and QGS) and the left ventricular reverse remodeling index (ΔLVESV) for the evaluation of left ventricular dyssynchrony in CRT patients is there. It also evaluated whether it could be an index of adaptation decision and effect determination. Methods: For 15 patients with severe heart failure who underwent CRT, GMPS was performed before (baseline) and after CRT. In cardioREPO®, standard deviation of the time to end systolic phase of 17 segments of the left ventricle (SDTES) and Bandwidth and Phase SD, Entropy of phase histogram were used as left ventricular dyssynchrony index. In QGS, standard deviation of the time to maximum displacement of each segment (SDTTMD) was used as an index. An example in which ΔLVESV (%Reduction) after 6 months of CRT decreased by 15% or more was defined as a CRT responder. Results: 10 of 15 patients were responders. Bandwidth at baseline of the responder group was significantly higher. SDTES, Phase SD, Entropy and SDTTMD of the responder group tended to be higher. All indexes decreased significantly in the responder group after 6 months of CRT but not in the non-responder group. Excluding SDTES, positive correlation was shown between baseline and ΔLVESV, and the optimal cutoff value of responder prediction was SDTES 7.637%, Bandwidth 218°, Phase SD 50.0°, Entropy 0.785, SDTTMD 19.85 ms. Conclusion: Phase analysis by GMPS showed that quantitative assessment of left ventricular dyssynchrony of CRT was possible and that the index was related to response prediction to CRT. In particular, SDTTMD showed good correlation between baseline and ΔLVESV, suggesting that it may be a more sensitive index of reaction prediction.

Ventricular dyssynchrony in pregnant women: A tissue Doppler study.

The aim of the study was to assess the left ventricular (LV) synchronicity in pregnant women and to identify the main determinants of LV dyssynchrony in asymptomatic pregnant women. One hundred sixty-seven pregnant women consecutively and 48 age-matched nonpregnant controls were enrolled. For the assessment of LV systolic dyssynchrony, the standard deviation of the time from QRS onset to peak systolic (Tps-LV- standard deviation [SD]) velocity and the maximal difference of the time from QRS onset to peak systolic velocity (Tps-LV) from 12 segments at the apical views. For the LV diastolic dyssynchrony, the standard deviation of the time from QRS onset to peak diastolic (Tpe-LV-SD) velocity and the maximal difference of the time from QRS onset to peak diastolic velocity (Tpe-LV) were calculated. Both systolic and diastolic dyssynchrony indexes were significantly higher in pregnant women than in the normal controls (Tps-LV; P<.01, Tps-LV-SD; P<.03, Tpe-LV, P<.05 and Tpe-LV-SD; P<.02). A total of 28 (16.8%) of the pregnant women had a dyssynchrony index above the accepted value for LV dyssynchrony (>34.4msec). There was a significant correlation between LV dyssynchrony indexes with, multiparty, multifetal pregnancies, systolic blood pressure in pregnant women with LV dyssynchrony. Additionally LV dyssynchrony was significantly associated with elevated E/e" and brain natriuretic peptide (BNP). Both systolic synchronicity and diastolic synchronicity were affected in pregnant women compared to nonpregnant women. LV dyssynchrony was significantly correlated with age, multiparity, and BNP level. Early detectable changes in systolic and diastolic synchrony may be present in pregnant women at higher risk of peripartum cardiomyopathy.

Left ventricular twist was decreased in isolated left bundle branch block with preserved ejection fraction.

Objective:Left ventricular (LV) rotation and twist play an important role in LV contraction and relaxation. Left bundle branch block (LBBB) deteriorates both diastolic and systolic functions. We evaluated the LV twist in patients with LBBB and preserved ejection fraction (EF) (>50%) to determine twist as a potential marker for subtle myocardial dysfunction.Methods:This observational cross-sectional study included 34 LBBB patients with preserved EF who were free from ischemic and valvular disease (Group 1) and 36 healthy controls (Group 2). All patients underwent 2-D Doppler and 2-D speckle tracking echocardiography. LV apical, basal rotation, and twist were evaluated in both groups and compared accordingly. In addition, subjects were dichotomized considering the median twist value of the study population. Binary logistic regression analysis was performed to determine the independent variables associated with inframedian twist.Results:Baseline clinical characteristics were similar in LBBB patients and controls. Mean apical rotation (2.5°±1.9° vs. 4.4°±2.9°; p=0.002), basal rotation (-2.9°±2.3° vs. -4.1°±2.7°; p=0.05), and twist (5.4°±3° vs. 8.6°±3.3°; p<0.001) were decreased in group 1. Parameters related to intra- and interventricular mechanical dyssynchrony, such as longitudinal left ventricular dyssynchrony index (LVdys) and preejection interval of LV, interventricular mechanical delay (IVMD), and left posterior wall contractions (SPMWD) were significantly higher in the LBBB group. The median twist value of the studied population was 6.65°. Binary logistic regression analysis showed that only presence of LBBB was independently associated with inframedian twist (OR=6.250; 95% CI: 2.215–17.632; p<0.001).ConclusionThe LBBB might have induced the reduction of LV twist by diminishing the LV rotation before inducing a prominent effect on the left ventricular ejection fraction (LVEF). Therefore, twist may be considered as a marker for subtle LV dysfunction in LBBB with substantially normal EF.

Association between left ventricular mechanics and diffuse myocardial fibrosis in patients with repaired Tetralogy of Fallot: a cross-sectional study

BackgroundPatients with repaired tetralogy of Fallot (TOF) have progressive, adverse biventricular remodeling, leading to abnormal contractile mechanics. Defining the mechanisms underlying this dysfunction, such as diffuse myocardial fibrosis, may provide insights into poor long-term outcomes. We hypothesized that left ventricular (LV) diffuse fibrosis is related to impaired LV mechanics.MethodsPatients with TOF were evaluated with cardiac magnetic resonance in which modified Look-Locker (MOLLI) T1-mapping and spiral cine Displacement encoding (DENSE) sequences were acquired at three LV short-axis positions. Linear mixed modeling was used to define the association between regional LV mechanics from DENSE based on regional T1-derived diffuse fibrosis measures, such as extracellular volume fraction (ECV).ResultsForty patients (26 ± 11 years) were included. LV ECV was generally within normal range (0.24 ± 0.05). For LV mechanics, peak circumferential strains (−15 ± 3%) and dyssynchrony indices (16 ± 8 ms) were moderately impaired, while peak radial strains (29 ± 8%) were generally normal. After adjusting for patient age, sex, and regional LV differences, ECV was associated with log-adjusted LV dyssynchrony index (β = 0.67) and peak LV radial strain (β = −0.36), but not LV circumferential strain. Moreover, post-contrast T1 was associated with log-adjusted LV diastolic circumferential strain rate (β = 0.37).ConclusionsWe observed several moderate associations between measures of fibrosis and impaired mechanics, particularly the LV dyssynchrony index and peak radial strain. Diffuse fibrosis may therefore be a causal factor in some ventricular dysfunction in TOF.

Impact of mitral geometry and global afterload on improvement of mitral regurgitation after trans-catheter aortic valve implantation.

ObjectiveTo assess the impact of mitral geometry, left ventricular (LV) remodelling and global LV afterload on mitral regurgitation (MR) after trans-catheter aortic valve implantation (TAVI).MethodsIn this study, 60 patients who underwent TAVI were evaluated by 3D echocardiography at baseline, 1 month and 6 months after procedure. The proportional change in MR following TAVI was determined by examining the percentage change in vena contracta (VC) at 6 months. Patients having a significant reduction of at least 30% in VC were defined as good responders (GR) and the remaining patients were defined as poor responders (PR).ResultsAfter 6 months of TAVI, 27 (45%) patients were GR and 33 (55%) were PR. There was a significant decrease in 3DE-derived mitral annular diameter and area (P = 0.001), mitral valve tenting area (TA) (P = 0.05), and mitral papillary muscle dyssynchrony index (DSI) (P = 0.05) in the GR group. 3DE-derived LVESV (P = 0.016), LV mass (P = 0.001) and LV DSI, (P = 0.001) were also improved 6 months after TAVI. In addition, valvulo-arterial impedance (ZVA) was significantly higher at baseline in patients with PR (P = 0.028). 3DE-derived mitral annular area (β: 0.47, P = 0.04), mitral papillary DSI (β: −0.65, P = 0.012) and ZVA (β: 0.45, P = 0.028) were the strongest independent parameters that could predict the reduction of functional MR after TAVI.ConclusionGR patients demonstrate more regression in mitral annulus area and diameter after significant decrease in high LVEDP and trans-aortic gradients with TAVI. PR patients appear to have increased baseline ZVA, mitral valve tenting and restriction in mitral valve coaptation. These factors are important for predicting the impact of TAVI on pre-existing MR.

Comparative study on ultrasonic assessments of left ventricular systolic synchronicity under different cardiac pacing modes

Objective To compare left ventricular (LV) synchronization of direct His-bundle pacing(DHBP) and right ventricular apical pacing (RVAP) with two-dimensional speckle tracking imaging (2D-STI) and tissue Doppler imaging (TDI), and discuss the diagnostic value of 2D-STI and TDI in evaluation of left ventricular systolic synchronicity. Methods Twenty-four patients implanted with DHBP and RVAP were observed. Conventional echocardiography examination were undergone both at the mode of DHBP or RVAP respectively. The time to peak radial strain of LV 18 segments were derived from the parasternal short-axis views by 2D-STI, then calculated the standard deviations (SD) and the maximal temporal difference of LV 18 segments (Trs-SD and Trs-Dif), and the interval of time to peak radial strain between the anteroseptal wall and the posterior wall(Tas-post). The time to peak systolic velocity of LV 12 segments were derived from the apical axis views by TDI. The SD and the maximal temporal difference of 12 segments (Ts-SD and Ts-Dif) were calculated as the LV dyssynchrony index. Results All the systolic synchrony parameters derived from 2D-STI and TDI were more significantly shortened in DHBP than in RVAP (all P<0.01). For DHBP, the detection rate of LV synchronization was higher by 2D-STI than by TDI. For RVAP the detection rate of LV dyssynchronization was also higher by 2D-STI than by TDI with RVAP lead (all P<0.05). Conclusions DHBP is more beneficial than RVAP in LV syschronization and LV function, RVAP may induce left ventricular systolic asynchrony. Both 2D-STI and TDI can assess the LV synchronization quantitatively, but 2D-STI may be more superior on the detection rate than TDI. Key words: Echocardiography; Cardiac pacing, artificial; Ventricular function, left

Late arrhythmia in patients with repaired tetralogy of Fallot: who is at risk?

Summary Tetralogy of Fallot (TOF) is the most common cause of cyanotic congenital heart defect. Over the last century, the life expectancy of TOF patients has significantly improved. This, however, has brought new challenges both to patients and their health-care providers, the main of them being late arrhythmia. Ironically, late arrhythmia is predominantly generated due to the fibrotic scars caused by the life-saving surgical repair. Once the first two mainly arrhythmia-free decades after the repair pass, the risk of developing late arrhythmia and, therefore, SCD becomes substantial. Consequently, young adults with repaired Tetralogy of Fallot (rTOF) require careful outpatient monitoring. There have been many attempts to predict the risk of life-threatening arrhythmia in rTOF patients. This has led to the defining of various risk factors, ranging from the widely used QRS prolongation to novel predictors, derived from cardiac magnetic resonance (CMR) based anatomical findings (left ventricular dyssynchrony indexes, right ventricular output tract akinetic length, right ventricular mass-to-volume ratio). The latter predictors have recently established CMR as a tool of high significance in evaluation of rTOF patients. Although the role of Holter monitoring findings in rTOF patient-assessment remains unclear, it may be useful in those who are 25 years and older. Implantable cardioverter–defibrillator (ICD) implantation is the first-line treatment for secondary prevention of sudden cardiac death (SCD). rTOF patients suffer from the highest rate of inappropriate and the lowest rate of appropriate ICD shocks, when compared to other congenital heart diseases. As a consequence, ICD implantation for primary SCD prevention should be carefully weighed. Catheter-based ablation therapy leads to high rate of initial success when abolishing monomorphic ventricular tachycardia and intra-atrial reentrant tachycardia, however recurrence rates remain high.