Left Ventricular Synchronicity Research Articles

Contradictory Effect of Coronary Collateral Circulation on Regional Myocardial Perfusion That Assessed by Quantitative Myocardial Perfusion Scintigraphy.

BackgroundPrevious studies showed conflicting results about the contribution of coronary collateral circulation (CCC) to myocardial perfusion and function. The aim of this study was to investigate these contradictory problems by gated myocardial perfusion scintigraphy (gated MPS) for the first time.MethodsThe current cohort was retrospectively selected among patients who underwent gated MPS and coronary angiography within 2 months. Two different groups including 96 patients were assessed by gated MPS to detect the understanding of the miscellaneous effect of CCC on myocardial perfusion. Group 1 consisted of those who had collateral arteries that were not-well-developed (Rentrop grade 0 - 1) (n = 58), while group 2 consisted of those who had collateral arteries that were well-developed (Rentrop grade 2 - 3) (n = 38).ResultsThere was no statistically significant difference between groups 1 and 2 in terms of perfusion and functional parameters obtained from gated MPS. Furthermore, no statistically significant difference was found in the phase analysis parameters which is a novel technique to evaluate left ventricular synchronization. On the other hand the left ventricular mass index values were high and quite close to the statistically significant value (P = 0.059) in group 2.ConclusionsThe current results that obtained by using the gated MPS technique for the first time in the evaluation of CCC showed that the well-developed collateral circulation has a positive effect on myocardial perfusion and function, but this effect was not statistically significant. Results need to be supported by large scale of patients’ size.

Positive impact of cardiac contractile modulation on myocardial contractility and left ventricular synchronization in a patient with a left ventricular noncompaction

The article provides a clinical case of a 58-year-old man with the fi rst clinical manifestation of chronic heart failure in the presence of a signifi cant decrease in the left ventricular ejection fraction. Left ventricular non-compaction cardiomyopathy was diagnosed by echocardiography. After 12 months, a cardiac contractility modulation device was implanted to the patient in the presence of disease progression despite optimal medical therapy. We assessed the course of disease, quality of life, exercise tolerance, and myocardial contractility of the patient before and six months after surgery. The methods of assessment were collection of patient complaints, physical examination, electrocardiography (ECG), fi lling out the Minnesota Living with Heart Failure Questionnaire (MLHFQ), sixminute walk test, spiroergometry, and echocardiography.

Evaluation of left ventricular systolic function and synchrony in patiests with early left breast cancer after breast conserving radiotherapy by layer-specific strain technique

Objective To evaluate the left ventricular systolic function and synchronization of patients with early left breast cancer after breast conserving radiotherapy by layer-specific strain technique. Methods Thirty-six patients with early left breast cancer who underwent breast surgery and radiotheraphy in Affiliated Tumor Hospital of Zhengzhou University from January 2018 to January 2019 were selected for this study. The layered strain technique was respectively applied to collect two-dimensional dynamic ultrasonic cardiograms one week before radiotherapy, one week after radiotherapy, and six months after radiotherapy. The EchoPAC 201 software was applied to analyze and obtain the global longitudinal peak strain(GLPS) and peak stain dispersion(PSD) of the epicardial layer(epi), the middle layer(mid) and endocardial layer(endo) of 17 left ventricular segments. The differences of every parameter before and after radiotherapy were compared, and the correlation of PSD and other parameters was analyzed. Results Compared with one week before radiotherapy, the absolute values of LPSepi, LPSmid, LPSendo, and GLPS all reduced significantly one week and six months after radiotherapy, and PSD increased significantly (P<0.05). Compared with one week after radiotherapy, the LPS absolute value of every layer and GLPS obviously reduced after six months, PSD obviously increased, the difference had statistical significance (P<0.05). PSD and GLPS displayed negative correlation one week after radiotherapy (r=-0.420, P<0.05), PSD and GLPS displayed negative correlation six months after radiotherapy (r=-0.641, P<0.05). Conclusions Layered strain technique can noninvasively and quantitatively evaluate the early changes of global and layered longitudinal peak strain and systolic synchrony of left ventricle in left breast cancer breast-conserving radiotherapy patients, and provides a new noninvasive test method for evaluating radioactive myocardial injury, and it has a certain guiding value to early clinical intervention and treatment of cardiovascular complications. Key words: Breast cancer, early; Radiotherapy; Layer-specific strain; Peak strain dispersion

Quantification of left ventricular performance in different phenotypes of hypertrophic cardiomyopathy

Objective To evaluate the characteristics of left ventricular structure, function, myocardial mechanics, hemodynamics and synchrony in different phenotypes of hypertrophic cardiomyopathy (HCM) using state-of-the-art echocardiography. Methods A consecutive series of 85 adult HCM patients who were admitted to the Xi Jing HCM center from January 2016 to November 2017 were collected. According to the peak left ventricular outflow tract pressure gradient in exercise stress echocardiography, the patients were divided into three groups: patients with non-obstructive HCM (n=28), those with labile-obstructive HCM (n=27), and those with obstructive HCM (n=30). In addition, 16 normal family members of HCM patients were included as control group. Two-dimensional speckle tracking imaging, tissue Doppler imaging and exercise stress echocardiography were used to evaluate the left ventricular function in resting and exercise states. Results ①As compared with the control group, left ventricular end-diastolic diameter decreased and left ventricular ejection fraction increased in all three HCM groups(all P 0.05). The obstructive HCM had the lowest mitral annular plane systolic excursion (MAPSE) and s′, and the longest systolic peaking time standard deviation(Ts-SD) and early diastolic peaking time standard deviation(Te-SD) (all P<0.05). The left ventricular diastolic function of obstructive HCM (e′, the E/e′ ratio and the left atrial volume index) was the worst, labile-obstruction and non-obstructive HCM were better, and the control group was the best (all P<0.001). ③During exercise, the GLS, GCS, GRS, twist of the left ventricle and the MAPSE were the lowest in the obstructive HCM, which increased in the labile-obstructive and non-obstructive HCM, and were best in the control group. The Ts-SD and Te-SD were the shortest in the control group, were prolonged in non-obstructive and labile-obstruction HCM, and were longest in obstructive HCM (all P<0.05). Additionally, the exercise time of the control group was the longest, followed by non-obstructive and labile-obstruction HCM, and the shortest in the obstructive HCM (all P<0.05). The METs of obstructive HCM were significantly lower than the other three groups (all P<0.05). Conclusions In obstructive HCM, the left ventricular systolic strain and synchronization, as well as the MAPSE, are significantly impaired in patients both at rest and during exercise. The patients with labile-obstructive and non-obstructive HCM have reduced left ventricular GLS, twist, and e′, but normal left ventricular GCS, GRS, synchrony, and MAPSE at rest, which are all impaired during exercise. Key words: Two-dimensional speckle tracking imaging; Tissue Doppler imaging; Hypertrophic cardiomyopathy; Exercise stress echocardiography; Myocardial mechanics; Synchrony

P6017Permanent left bundle branch area pacing for atrioventricular block: feasibility, safety and acute effect

Abstract Background Left bundle branch area pacing (LBBAP), lacks adequate evaluation for AVB. Purpose We aimed to assess the feasibility, safety, and acute clinical outcomes of permanent LBBAP in patients with AVB. Methods We retrospectively recruited AVB patients with indication for ventricular pacing who had underwent LBBAP from May to Sep. 2018. ECG characteristics, pacing parameters, echocardiographic parameters and adverse events were evaluated during follow-up. Successful LBBAP was defined as the paced QRS morphology of RBBB pattern and QRSd less than 130ms. Results A total of 33 patients were involved in this study (mean age: 55.1±18.5 years; 66.7% male, 48.4% with bundle branch block,BBB). LBBAP was successfully performed in 90.9% (30/33) of all patients. The mean capture threshold of LBBAP was 0.76±0.26 V/0.4 ms during the procedure and 0.64±0.20 V/0.4ms at 3-month follow-up. The paced QRSd was 112.8±10.9 ms during the procedure and 116.8±10.4ms at 3-month follow-up. Baseline left or right BBB was corrected by LBBAP (153.3±27.8 ms vs. 122.2±9.9 ms) with a success rate of 68.7% (11/16). One ventricular septal lead perforation occurred soon after the procedure and LBBAP was successfully repeated by lead revision. Cardiac function and left ventricular synchronization at three-month follow-up presented slightly improvement as compared with baseline. Table 1. Complications and changes in pacing parameters within 3 months after LBBAP Pacing parameters LBBAP (N=30) During the procedure Before discharge 3-month follow up Sensing amplitude, mV 14.4±5.1 15.8±11.7 14.6±4.6 Pacing threshold@0.4ms, V 0.76±0.26 0.59±0.16 0.64±0.20 Pacing impedance, Ω 691.7±133.8 588.0±79.3 554.7±93.7 Paced QRSd at 3.0V@0.4 ms output, ms 112.8±10.9 114.4±14.2 116.8±10.4 VP, % NA NA 79.4±24.6 Complications, n (%) 1 (3.3) 0 (0.0) 0 (0.0) Infection, n (%) 0 (0.0) 0 (0.0) 0 (0.0) Septal perforation, n (%) 1 (3.3) 0 (0.0) 0 (0.0) Dislodgement, n (%) 0 (0.0) 0 (0.0) 0 (0.0) QRSd, QRS duration; VP, ventricular pacing percentage. Figure 1. Characteristics of LBBAP Conclusion Permanent LBBAP yielded stable threshold, narrow QRSd and preserved left ventricle synchrony with few complications. Our preliminary results indicate that LBBAP holds promise as an attractive physiological pacing strategy for AVB.

P4378Comparison between left bundle branch pacing and His bundle pacing using two-dimensional speckle tracking echocardiography

Abstract Background Although his bundle pacing (HBP) can achieve physiological electrical activation of the ventricles, its clinical use is limited by lower success rates, high and unstable pacing thresholds and loss of capture. Left bundle branch pacing (LBBP) has been proved to be able to correct Left bundle branch block (LBBB) and generate a narrower QRS duration than conventional RV pacing. However, its effects on ventricular synchronism and contraction function remains unknown. The current study is aimed to compare the echocardiographic characteristics between HBP and LBBP, and to explore whether LBBP leads to a comparable cardiac synchrony and deformation in comparison with HBP. Methods Forty-six pacing-indicated patients were prospectively enrolled. Twenty-nine patients underwent LBBP (17 male patients, mean age 69.6±13.7yrs, the LBBP group) and 17 patients underwent HBP (13 male patients, mean age 70.4±14.7yrs, the HBP group). LBBP was achieved by trans-septal method in the basal ventricular septum. Left ventricular end diastolic volume (LVEDV), left ventricular end systolic volume (LVESV), left ventricular ejection fraction (LVEF), and tricuspid annulus plane systolic excursion (TAPSE) were obtained. Strains and time to peak strains of right ventricular free wall and 16 left ventricle segments were analyzed using two-dimensional speckle tracking echocardiography (2D STE). The standard deviation of time to peak strains of 16 left ventricular segments was calculated as PSD. Results Compared to the baseline, time to peak longitudinal strain (TTPS) of apical septum, apical lateral wall were shortened after 6 months of HBP, while they didn't change significantly after 6 months of LBBP. After pacemaker implantation, the LBBP group had a delayed TTPS of apical septum, apical lateral wall and basal RV free wall than the HBP group (LBBP vs. HBP: apical septum,358.44±61.98ms vs. 296.43±29.47ms; apical lateral wall, 373.11±55.80ms vs. 299.00±83.45ms; basal RV free wall, 404.31±72.93ms vs. 334.50±39.95ms, all p&lt;0.05).However, PSD was comparable between the two groups (p&gt;0.05). Compared to the baseline, global left ventricular longitudinal strain (LVGLS) and longitudinal strain of RV free wall (RVLS) were deteriorated after 6 months of HBP, while they were preserved in the LBBP group. After 6-month pacing, LVGLS and RVLS were significantly stronger in the LBBP group than those in the HBP group. (LVGLS, −16.10±3.75% vs. −13.18±4.11%; RVLS, −17.50±5.46% vs. −13.70±4.35%, both p&lt;0.05). Conclusion Patients received LBBP had a comparable left ventricular synchronism and a better myocardial contraction compared to patients with HBP. LBBP may be a promising alternative pacing strategy. Two-dimensional STE is more sensitive than conventional echocardiography in assessing cardiac synchrony and segmental deformation.

Permanent left bundle branch area pacing for atrioventricular block: Feasibility, safety, and acute effect

Left bundle branch area pacing (LBBAP), a new pacing approach, lacks adequate evaluation. To assess the feasibility, safety, and acute effect of permanent LBBAP in patients with atrioventricular block (AVB). A total of 33 AVB patients with indications for ventricular pacing were recruited. Electrocardiograms, pacing parameters, echocardiographic measurements, and complications associated with LBBAP were evaluated perioperatively and at 3-month follow-up. Successful LBBAP was defined as a paced QRS morphology of right bundle branch block pattern in lead V1 and QRS duration (QRSd) less than 130 ms. LBBAP was successfully performed in 90.9% (30/33) of patients (mean age: 55.1 ± 18.5 years; 66.7% male). The mean capture threshold was similar during the procedure (0.76 ± 0.26 V at 0.4 ms) and at the 3-month follow-up (0.64 ± 0.20 V at 0.4 ms). The paced QRSd was 112.8 ± 10.9 ms during the procedure and 116.8 ± 10.4 ms at the 3-month follow-up. Baseline left or right bundle branch block was corrected (intrinsic QRSd 153.3 ± 27.8 ms vs paced QRSd 122.2 ± 9.9 ms) with a success rate of 68.7% (11/16). One ventricular septal lead perforation occurred soon after the procedure with characteristics of pacing failure, and lead revision was successful. Cardiac function and left ventricular synchronization by 2-dimensional echocardiographic strain imaging at the 3-month follow-up slightly improved compared with that at baseline. Permanent LBBAP yielded a stable threshold, a narrow QRSd, and preserved left ventricular synchrony with few complications. Our preliminary results indicate that LBBAP holds promise as an attractive physiological pacing strategy for AVB.

Left ventricular mechanics before and after myectomy in patients with hypertrophic obstructive cardiomyopathy

Objectives The objective of this paper is to detect changes in left ventricular (LV) mechanics after surgical myectomy in patient with hypertrophic obstructive cardiomyopathy (HOCM). Background Septal myectomy is the gold standard method to relieve LV outflow tract pressure gradient in patients with HOCM. Myocardial mechanics are abnormal in those patients, demonstrating low longitudinal strain, high circumferential strain, and high apical rotation, compared with healthy patients. The aim of this study was to determine whether functional improvement after myectomy is associated with improved myocardial mechanics. Patients and methods A total of 15 patients (60% males and 40% female) with HOCM refractory to medical treatment were subjected to septal myectomy. Clinical data and paired echocardiographic studies before and within 6 months after myectomy were analyzed and compared. Myocardial mechanics including longitudinal and circumferential strain and rotation and LV synchronization were assessed using two-dimensional strain software (velocity vector imaging). Results Results showed significant symptomatic relief. LV outflow gradient decreased dramatically from 63.13 ± 10.25 to 9.96 ± 2.72 mmHg (P < 0.0001) and left atrial volume index decreased from 37.8 ± 5.61 to 26.38 ± 3.37 cm3/m2 (P < 0.05). E/e′ decreased from 15.23 ± 2.39 to 9.18 ± 1.42 (P < 0.05). Low longitudinal strain decreased at the myectomy site (basal septum), increased in the basal inferior segment, and remained unchanged globally − 6.43 ± 6.54 to − 8.70 ± 2.30 (P = 0.232). High circumferential strain decreased from − 28.47 ± 3.35 to − 18.26 ± 2.86 (P < 0.05). High LV twist normalized from 16.52 ± 2.25 to 14.02 ± 2.27 (P < 0.05). Conclusion Patients with HOCM show mechanical adaptations to chronic elevated afterload similar to patients with severe aortic stenosis in whom there is increased circumferential strain, increased basal and apical rotation, and LV twist. However, within 6 months after myectomy, global longitudinal strain remained unchanged, circumferential strain and rotation decreased, LV twist normalized, and LV dyssynchrony showed no significant changes. Thus, improvement of symptoms after myectomy is mainly because of improvement of the predictors of diastolic function.

Assessment of left ventricular systolic function and synchronicity in patients after coronary artery bypass using layer-specific strain technology

Objectives To explore the application values of layer-specific strain technology in the assessment of left ventricular (LV) systolic function and synchronicity before and after coronary artery bypass graft (CABG) in patients with coronary artery disease (CAD). Methods Thirty-three CAD patients scheduled for CABG were recruited, along with 35 controls without cardiovascular disease. The images of apical four, two and three chamber views of LV were collected before CABG and 1 week, 1 month and 3 months after CABG. The layer-specific longitudinal peak strains, time to peak and peak strain dispersion (PSD) were determined for 17 segments of LV using Echo PAC workstation software and Q-analysis software. The differences of these parameters were compared between groups. Results The absolute values of layer-specific longitudinal peak strains at subendocardium, middle layer and subepicardium, respectively represented by GLPSendo, GLPSmid and GLPSepi, decreased significantly (P 0.05) and absolute values of GLPSendo, GLPSmid and GLPSepi 3 months after CABG (P>0.05). At 1 month and 3 months, PSD decreased significantly (P 0.05). Conclusions Layer-specific strain technology provides a quantitative evaluation approach for LV systolic function and synchronicity before and after CABG in CAD patients. As a novel parameter in assessing LV systolic synchronicity, PSD is worthy of clinical popularization.

Assessment of Permanent Selective His Bundle Pacing in Left Ventricular Synchronization Using 3-D Speckle Tracking Echocardiography

The study described here aimed to evaluate left ventricular (LV) systolic mechanical synchronization during permanent selective His bundle pacing (SHBP) using 3-D speckle-tracking echocardiography post-operatively and 6 mo after pacemaker implantation in 62 patients randomly assigned to SHBP (n = 32) or right ventricular apical pacing (RVAP, n = 30). A standard apex four-chamber view was exposed and was transformed into full-volume mode under 3-D echocardiography. Three-dimensional speckle-tracking echocardiography was analyzed offline. The primary endpoint was LV mechanical synchronization post-operatively and during the 6-mo follow-up. Significant LV dyssynchrony was detected while evaluating the maximum time difference and standard deviation of 16-segment systolic time to peak 3-D strain at 1 wk and 6 mo. The pacing thresholds were significantly higher in the SHBP than in the RVAP group throughout follow-up. The R-wave amplitude was significantly lower in the SHBP group than with RVAP. The pacing parameters during SHBP were as stable as during conventional RVAP during the mid-term follow-up. In conclusion, 3-D speckle-tracking echocardiography is feasible and provides a more convenient method for evaluating LV synchrony.

Ischaemic aetiology predicts exercise dyssynchrony in patients with heart failure with reduced ejection fraction.

Left ventricular (LV) dyssynchrony is common in patients with heart failure with reduced ejection fraction (HFREF). However, various conditions including exercise may alter its presence. LV dyssynchrony at exercise (ExDYS) has been associated with lower cardiac performance and exercise capacity but with higher cardiac resynchronization therapy (CRT) response. Therefore, understanding mechanisms underlying ExDYS may improve patient selection for CRT. To investigate for predictors of ExDYS among patients with HFREF and prolonged QRS duration. Consecutive patients with stable, chronic HF, LVEF<35%, sinus rhythm and QRS≥120ms were eligible. 2D echocardiography and tissue-Doppler were performed at rest and peak cyclo-ergometer exercise to assess LV systolic (LVEF) and diastolic function [mitral E-to-e'-wave velocities (E/e')] and dyssynchrony. Dyssynchrony was defined as a maximal difference between time-to-peak systolic velocities of≥65ms from opposing basal segments. We included 48 patients (aged 63.7±12.2, 81.3% male). Ischaemic aetiology (ICM) was present in 23 (47.9%). Dyssynchrony at rest (rDYS) was present in 32 (66.6%) patients, while ExDYS in 23 (47.9%). ExDYS correlated with ICM, lower LVEF and higher E/e' ratio. ICM remained significant predictor of ExDYS in multiple regression model (OR:4.3, 95%CI:1.2-15.7, p=003). On exercise, 19 (39.5%) patients changed the rDYS status. While, exercise-induced dyssynchronization was observed only in ICM patients, exercise-induced resynchronization was more likely in patients with lower rest E/e' ratio (OR:0.85, 95%CI:0.75-0.97, p=0.02). Ischaemic aetiology of HFREF is an important predictor of ExDYS. Restoration of LV synchronicity during exercise is more likely in patients with less advanced LV diastolic dysfunction.

Evaluation of left ventricular systolic function and synchronicity in patients with maintenance hemodialysis by layer-specific strain

Objective To explore the systolic function and synchronicity of left ventricle (LV) in patients with maintenance hemodialysis(MHD) by layer-specific strain. Methods Forty-three patients with MHD and 48 healthy controls were studied. Three consecutive cardiac cycles two-dimensional dynamic images including standard LV apical two-chamber, long-axis and four-chamber views and LV short-axis views at the levels of basal, middle and apical were acquired. A quantitative software called EchoPAC was used to analyze longitudinal strain(LS) and circumferential strain(CS) of these six dynamic images and peak strain dispersion(PSD) was automatic computed by the software. The difference of these parameters between the two groups and the correlation between PSD and other parameters were studied. Results Parameters of global layer-specific strain: compared with the control group, global LS and CS of subendocardial, midmyocardial, epicardial and full-thickness myocardium layers were decreased in the MHD group (P 0.05). Parameters of synchronicity: PSD of MHD group was larger than that of control group(t=6.094, P<0.001). PSD was positively correlated with longitudinal strain of full-thickness (GLS) in MHD group (rs=0.478, P=0.039). Conclusions Layer-specific strain can noninvasively and accurately quantitate left ventricular systolic function and synchronicity in patients with MHD. Key words: Echocardiography; Renal dialysis; Ventricular function, left; Layer-specific strain

Prominent differences in left ventricular performance and myocardial properties between right ventricular and left ventricular-based pacing modes in rats

Biventricular pacing is an important modality to improve left ventricular (LV) synchronization and long-term function. However, the biological effects of this treatment are far from being elucidated and existing animal models are limited and demanding. Recently, we introduced an implanted device for double-site epicardial pacing in rats and echocardiographically demonstrated favorable effects of LV and biventricular (LV-based) pacing modes typically observed in humans. Here, this new animal model was further characterized. Electrodes were implanted either on the right atria (RA) and right ventricle (RV) or on the RV and LV. Following recovery, rats were either used for invasive hemodynamic measurements (pressure-volume analysis) or exposed to sustained RV vs. biventricular tachypacing for 3 days. RV pacing compromised, while LV-based pacing modes markedly enhanced cardiac performance. Changes in LV performance were associated with prominent compensatory changes in arterial resistance. Sustained RV tachypacing increased the electrocardiogram QTc interval by 7.9 ± 3.1 ms (n = 6, p < 0.05), dispersed refractoriness between the right and left pacing sites and induced important molecular changes mainly in the early-activated septal tissue. These effects were not observed during biventricular tachypacing (n = 6). Our results demonstrate that the rat is an attractive new model to study the biological consequences of LV dyssynchrony and resynchronization.

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.

Development and validation of an automatic method to detect the latest contracting viable left ventricular segments to assist guide CRT therapy from gated SPECT myocardial perfusion imaging

ObjectivesThe purpose of this study is to use ECG-gated SPECT MPI to detect the latest contracting viable left ventricular (LV) segments to help guide the LV probe placement used in CRT therapy and to validate segment selection against the visual integration method by experts. MethodsFor each patient, the resting ECG-gated SPECT MPI short-axis images were sampled in 3D to generate a polar map of the perfusion distribution used to determine LV myocardial viability, and to measure LV synchronicity using our phase analysis tool. In the visual integration method, two experts visually interpreted the LV viability and mechanical dyssynchrony from the short-axis images and polar maps of viability and phase, to determine the latest contracting viable segments using the 17-segment model. In the automatic method, the apical segments, septal segments, and segments with more than 50% scar were excluded as these are not candidates for CRT LV probe placement. Amongst the remaining viable segments, the segments, whose phase angles were within 10° of the latest phase angle (the most delayed contracting segment), were identified for potential CRT LV probe placement and ranked based on the phase angles of the segments. Both methods were tested in 36 pre-CRT patients who underwent ECG-gated SPECT MPI. The accuracy was determined as the percent agreement between the visual integration and automatic methods. The automatic method was performed by a second independent operator to evaluate the inter-operator processing reproducibility. ResultsIn all the 36 patients, the LV lead positions of the 1st choices recommended by the automatic and visual integration methods were in the same segments in 35 patients, which achieved an agreement rate of 97.2%. In the inter-operator reproducibility test, the LV lead positions of the 1st choices recommended by the two operators were in the same segments in 25 patients, and were in the adjacent segments in 7 patients, which achieved an overall agreement of 88.8%. ConclusionsAn automatic method has been developed to detect the latest contracting viable LV segments to help guide the LV probe placement used in CRT therapy. The retrospective clinical study with 36 patients suggests that this method has high agreement against the visual integration method by experts and good inter-operator reproducibility. Consequently, this method is promising to be a clinical tool to recommend the CRT LV lead positions.

The Effects of Ivabradine on Left Ventricular Synchronization and Tei Index in Patients with Systolic Heart Failure.

The aim of our study was to evaluate in stable outpatients with systolic heart failure (HF) the 3 months effect of ivabradine on LV synchronization and Tei index in stable outpatients with systolic HF. We evaluated prospectively 40 (30 males, 10 females) patients with HF. All patients were evaluated before and after treatment by transthoracic M mode, two dimensional (2D), pulsed-wave (PW), continuous wave (CW), color flow and tissue Doppler imaging (TDI) and tissue synchronization imaging (TSI). Standard deviation of Ts of the 12 LV segments (Ts-SD-12) is the most widely used parameter of intra-LV asynchrony. Thirty men and 10 women with mean ± SD age of 64.7 ± 9.9 years were included in this study. Most of the patients benefitted from some degree of clinical improvement, 12/16 (75.0%) from NYHA III to II and 18/24 (75.0%) from II to I, respectively. Resting heart rate was significantly reduced after ivabradine treatment (84.3 ± 11.4 vs. 66.5 ± 11.5 bpm, p < 0.001). E/E' and Tei index were significantly changed after ivabradine treatment (17.3 ± 9.0 vs. 14.8 ± 7.1, p = 0.02 and 0.86 ± 0.74 vs. 0.81 ± 0.69, p = 0.02). Intra-LV synchrony parameters Ts-SD-12 and Ts-12 were significantly reduced after ivabradine (46.8 ± 13.6 vs. 42.7 ± 13.1, p = 0.01 and 142.5 ± 44.0 vs. 128.5 ± 45.2, p = 0.009). The present study demonstrated that adding ivabradine to the standard therapy reduced HR and significantly improved LV ventricular asynchrony and Tei index in systolic HF patients.

Effect of sevoflurane anesthesia on left ventricular synchronization in patients undergoing coronary artery bypass grafting

Objective To evaluate the effect of sevoflurane anesthesia on left ventricular synchronization in patients undergoing coronary artery bypass grafting (CABG). Methods Twenty-six patients of both sexes, aged 45-75 yr, with body mass index of 19-30 kg/m2 and body surface area 1.4-2.0 m2, of American Society of Anesthesiologists physical status Ⅱ or Ⅲ and New York Heart Association class Ⅱor Ⅲ, undergoing elective CABG with cardiopulmonary bypass, were divided into 2 groups using a random number table: control group (group C, n=11) and sevoflurane group (group S, n=15). After induction of general anesthesia, the patients were endotracheally intubated and mechanically ventilated.Anesthesia was maintained with iv infusion of propofol 4-6 mg·kg-1·h-1, remifentanil 0.2-0.3 μg·kg-1·min-1 and cisatracurium 0.10-0.15 mg·kg-1·h-1, and intermittent iv boluses of fentanyl 0.5 μg/kg, and bispectral index value was maintained at 40-60.In group S, sevoflurane (end-tidal concentration: 2.05% for 45-49 yr, 1.80% for 50-59 yr, 1.60% for 60-75 yr) was inhaled for 30 min starting from 15 min after termination of cardiopulmonary bypass, followed by 30 min washout.The parameters of cardiac function were monitored using transesophageal echocardiography.After induction and before sternotomy, immediately before sevoflurane inhalation, at 30 min of sevoflurane inhalation, and at 30 min of washout, heart rate, mean arterial pressure, central venous pressure, pulmonary artery occlusion pressure, cardiac output, left ventricular ejection fraction, standardized standard deviation of time to peak systolic longitudinal strain of R-R interval (Tssl-SD) of 17 left ventricular segment, and standardized standard deviation of time to peak systolic circumferential strain of R-R interval (Tssc-SD) of 16 left ventricular segment were recorded. Results Cardiac output and left ventricular ejection fraction were within in the normal ranges in the two groups.Compared with group C, heart rate was significantly decreased at 30 min of sevoflurane inhalation and 30 min of washout, and mean arterial pressure, cardiac output and left ventricular ejection fraction were significantly decreased at 30 min of sevoflurane inhalation in group S (P 0.05). Conclusion Sevoflurane anesthesia has no marked effect on the left ventricular synchronization in patients undergoing CABG. Key words: Anesthetics, inhalation; Coronary artery bypass; Cardiac pacing, artificial; Heart ventricles

The effect of dexmedetomidine on left ventricular synchronization in patients undergoing coronary artery bypass grafting

Objective This study was designed to investigate the role of dexmedetomidin(Dex) on left ventricular synchronization in patients undergoing coronary artery bypass grafting(CABG) with CPB. Methods Twenty-one patients were selected using a random number table. These patients were classified as New York Heart Association(NYHA) class Ⅱ, Ⅲ and ASA physical statusⅡ,Ⅲ with age of 45-74 y and weight of 52-85 kg. They were further divided into Dex group(group D, n=10) and control group(group C, n=11). After stopping CPB for 15 min, a loading dose of Dex at 0.5 μg/kg was injected intravenously 10 min after stopping CPB for 15 min followed by infusion at 0.5 μg·kg-1·h-1 until the end of operation in group D, while equal volume of normal saline was given in group C. At the time of before sternotomy(T0), stopping CPB for 15 min(T1), injection of Dex for 30 min(T2) and for 1 h (T3), the MAP, HR, CVP, pulmonary artery occlusion pressure(PAOP) and transesophageal echocardiography(TEE) monitoring indicators including left ventricular ejection fraction (LVEF) and cardiac output(CO), stroke volume(SV), standard deviation of time to maximum systolic velocity of the 17 left ventricular segments of longitudinal strain(Tssl-17-SD) and standard deviation of time to maximum systolic velocity of the 16 left ventricular segments of circumferential strain(Tssc-16-SD) were recorded. Results The HR were statistically lower in group D[(71.0±5.4), (69.3±2.8) bpm] than those in group C[(89.5±14.7), (89.4±14.0) bpm] at T2, T3(P<0.05). CO in group D[(4.4±1.2) L/min] was statistically lower than that in group C[(5.8±1.5) L/min] at T2(P<0.05). Compared with group C, Tssl-17-SD was statistically increased at T2 in group D(P<0.01). Conclusions In patients undergoing CABG with CPB, the injection of Dex after CPB may inhibit the synchronized movement of the left ventricular longitudinal strain. Key words: Dexmedetomidine; Coronary artery bypass grafting; Left ventricle; Systolic synchrony; Standard deviation of time to maximum systolic velocity

Functional characteristics of left ventricular synchronization via right ventricular outflow-tract pacing detected by two-dimensional strain echocardiography

BackgroundRecently, due to the detrimental effects on the ventricular function associated with right ventricular apical (RVA) pacing, right ventricular septal (RVS) pacing has become the preferred pacing method. However, the term RVS pacing refers to both right ventricular outflow-tract (RVOT) and mid-septal (RVMS) pacing, leading to a misinterpretation of the results of clinical studies. The purpose of this study, therefore, was to elucidate the functional differences of RVA, RVOT, and RVMS pacing in patients with atrioventricular block. MethodsWe compared the QRS duration, global longitudinal strain (GLS), and left ventricular (LV) synchronization parameters at the three pacing sites in 47 patients. The peak systolic strain (PSS) time delay between the earliest and latest segments among the 18 LV segments and standard deviation (SD) of the time to the PSS were also calculated for the 18 LV segments at each pacing site using two-dimensional (2D) strain echocardiography. ResultsRVMS pacing was associated with a significantly shorter QRS duration compared with RVA and RVOT pacing (154.4±21.4 vs 186.5±19.9 and 171.1±21.5ms, P<0.001). In contrast, RVOT pacing revealed a greater GLS (−14.69±4.92 vs −13.12±4.76 and −13.51±4.81%, P<0.001), shorter PSS time delay between the earliest and latest segments (236.0±87.9 vs 271.3±102.9 and 281.9±126.6%, P=0.007), and shorter SD of the time to the PSS (70.8±23.8 vs 82.7±30.8 and 81.5±33.7ms, P=0.002) compared with RVA and RVMS pacing. ConclusionsThese results suggest that the functional characteristics of RVOT pacing may be a more optimal pacing site than RVMS, regardless of the pacing QRS duration, in patients with atrioventricular conduction disorders.

Relationship between the myocardial 99Tcm-MIBI uptake and the left ventricular synchronization in patients with dilated cardiomyopathy

Objective To analyze the relationship between left ventricular myocardial 99Tcm-MIBI uptake and the left ventricular synchronization in patients with dilated cardiomyopathy (DCM). Methods Forty-three cases (30 males and 13 females, age (50.58±13.29) years) with DCM who underwent 12-lead electrocardiogram and rest gated MPI were included. Among them, 24 cases with QRS duration <120 ms was regarded as synchronous group, and 19 cases with QRS duration≥120 ms was regarded as dyssynchronous group. LVEF, PFR, ESV, EDV were recorded, and myocardial uptake of 99Tcm-MIBI, severity and extent in area of apex, anterior, lateral, inferior and septum wall of left ventricle were calculated respectively by quantitative perfusion SPECT (QPS)software. Independent sample t test and Mann-Whitney u test were used for data analysis with IBM SPSS 21.0. Results The values of LVEF were (26.44±5.59)% and(23.70±5.27)% in synchronous group and dyssynchronous group respectively (t=1.240, P>0.05). The other three cardiac function parameters had no significant differences between the two groups (t: 0.195, 0.113, 0.291, all P>0.05). There were no significant differences of myocardial 99Tcm-MIBI uptake between two groups in all segments of apex, anterior, lateral, inferior and septum wall (t: -0.712-1.059, all P>0.05). Deeper severities (0.6-3.3 s) and wider abnormal extents (0-65%) of myocardial 99Tcm-MIBI uptake were found only in the area of inferior wall in synchronous group, compared to those in dyssynchronous group (0.1-2.5 s, 0-36%; z=-2.266, -2.391, both P<0.05). Conclusions Myocardial injury (location, severity and extent)in patients with DCM could be detected by myocardial 99Tcm-MIBI imaging. The severity and extent of myocardial injury may have a significant impact on the left ventricular synchronization. Key words: Cardiomyopathy, congestive; Tomography, emission-computed, single-photon; MIBI