Interventricular Asynchrony Research Articles

Comparative evaluation of permanent cardiac pacing modes in patients with arrhythmic variant of coronary artery disease (bradyarrhythmia)

Aim – to analyze and compare the results of permanent cardiac pacing therapy in patients with arrhythmic variant of coronary artery disease (CAD) (grade II – III AV block and sinus node weakness syndrome).
 Material and methods. We studied the results of examination of 63 patients with arrhythmic variant of coronary artery disease (sinus node weakness syndrome and AV block), who received pacing therapy in VVI and DDD modes in the Department of Rhythm and Conduction Disorders of the Republican Clinical Hospital No. 4. All patients underwent clinical, laboratory and instrumental tests in accordance with federal clinical guidelines for CAD, rhythm and conduction disorders.
 Results. The left ventricular ejection fraction (LVEF) in patients with pacemakers in VVI mode was 9% lower when compared to LVEF in DDD mode. Mitral regurgitation was 47.6% more common in patients having VVI mode than DDD mode. In patients with the VVI regimen, the interventricular septal asynchrony was 25.1% more common and was accompanied by more pronounced left ventricle hypertrophy and dysfunction. Pacemaker syndrome was observed in 3 (7.5%) patients with VVI stimulation mode, stopped by reimplantation of a two-chamber frequency–adaptive pacemaker, and in 1 (4.35%) patient with DDD mode, eliminated by reprogramming.
 Conclusion. In patients with coronary artery disease, the effectiveness of pacing in correction of the cardiac rhythm and conduction depends on the treatment mode. Disorders of myocardial contractility are more pronounced in patients with VVI mode, if compared to DDD mode.

Pacing-induced cardiomyopathy in patients with permanent right ventricular pacing and preserved left ventricle systolic function: characteristics, methods of treatment and prevention

The aim – to determine the frequency of occurrence and describe the characteristics of pacing-induced cardiomyopathy (PICM) in patients with permanent right ventricular pacing (at least 90 %) and preserved left ventricular ejection fraction (LVEF) (≥ 50 %).Materials and methods. The study included 34 patients with indications for permanent ventricular pacing who had pacemaker implantation from 2012 to 2022 (mean follow-up period was 44.97±28.45 months). PICM was defined as a decrease in LVEF < 45 % during follow-up.Results and discussion. The incidence of PICM in this study was 26 %. The average value of LVEF and EDI at the time of the control follow-up was significantly different in the PICM group and non-PICM group: 38.6±5.9 vs. 53.5±5.7 % (p<0.001) and 97.90±20.75 vs. 60.90±19.32 ml/m2 (p<0.001). All patients from the study group during follow-up went through protocol echocardiography, at which intraventricular and interventricular asynchrony were examined, the number of left ventricular segments with reduced deformation were fixed, and the global longitudinal deformation of the left ventricle (GLS) was calculated. The values of these parameters differed significantly in the PICM group and non-PICM group: intraventricular asynchrony was 261.1±61.0 vs. 146.1±62.8 ms (p<0.001), interventricular asynchrony 91.0±36.4 vs. 54.2±22.2 ms (p=0.014), the number of segments with reduced deformation 8.1±2.6 vs. 3.91±2.30 (p<0.001), GLS -9.7±2.6 vs. -14.9±3.4 (p<0.001). At the time of the follow-up examination, sensitivity on ventricular lead in the PICM group was significantly reduced compared to patients with preserved LVEF (6.26±4.02 vs. 11.56±3.86 mV; p=0.045). The paced QRS width in the PICM group was significantly greater (163.0±22.7 vs. 150.8±14.5; p=0.046) and there were more patients with rate-adapted cardiac pacing in the PICM group (4 (40 %) vs. 2 (8 %)), p=0.0305).Conclusions. According to the obtained data, cardiomyopathy due to right ventricular pacing develops rather instantaneously in the first years after PM implantation, rather than slowly progressing over time, although a multivariate regression analysis of risk factors for the development of PICM has yet to be performed on the obtained clinical data. Biventri­­­cular paicng effectively eliminates the consequences of non-physiological right ventricular myocardial paicng, improves LV systolic function. Conduction system pacing may potentially reduce the risk of right ventricular pacing-induced cardiomyopathy in patients with preserved LVEF.

Predictors of Pacing-Induced Cardiomyopathy in Patients with Permanent Right Ventricular Pacing and Preserved Left Ventricular Systolic Function

Right ventricular pacing may impair left ventricular systolic function in patients with reduced left ventricular ejection fraction (LVEF).
 The aim. To determine the frequency of pacing-induced cardiomyopathy (PICM) in patients with permanent right ventricular pacing (at least 90%) and preserved LVEF (≥50%). To determine the risk factors for the occurrence of PICM.
 Materials and methods. The study included 34 patients with indications for permanent ventricular pacing in whom pacemaker was implanted from 2012 to 2022 (mean follow-up period 44.97 ± 28.45 months). PICM was defined as a decrease in LVEF <45% during follow-up regardless of clinical manifestations. Risk factors for PICM were determined through univariate and multivariate regression analysis.
 Results. The incidence of PICM in this study was 26% during the mean observation period of 44.9 ± 28.4 months. The mean time to the onset of PICM was 29 months in 5 out of 9 patients (55%), the time from implantation to diagnosis of PICM was less than a year. The mean LVEF and end-diastolic volume index at the time of follow-up differed significantly in the groups with and without PICM: 38.6 ± 5.9% vs. 53.5 ± 5.7% (p<0.001) and 97.9 ± 20.75 ml/m2 vs. 60.9 ± 19.32 ml/m2 (p<0.001), respectively. In the PICM group intraventricular asynchrony was 261.1 ± 61 ms vs. 146.1 ± 62.8 ms (p<0.001), interventricular asynchrony 91 ± 36.4 ms vs. 54.2 ± 22.2 ms (p = 0.014), the number of segments with reduced deformation 8.1 ± 2.6 vs. 3.91 ± 2.3 (p<0.001), global longitudinal strain –9.7 ± 2.6 % vs. –14.9 ± 3.4 % (p<0.001). At the time of the follow-up examination, the signal of sensitivity on ventricular lead in the PICM group was significantly reduced compared to patients without PICM (6.26 ± 4.02 mV vs. 11.56 ± 3.86 mV, p = 0.045). Paced QRS width in the PICM group was significantly larger (163 ± 22.7 ms vs. 150.8 ± 14.5 ms) and there were more patients with rate-adapted cardiac pacing in the PICM group: 4 (40%) vs. 2 (8%) (p = 0.0428). In multivariate regression analysis, a wider paced QRS (hazard ratio 1.09 for every 1 ms increment in QRS width, 95% confidence interval 1.01-1.17, p = 0.025) was an independent predictor of PICM. In two patients from PICM group, upgrade of pacemaker system to biventricular pacing was performed with an improvement in the left ventricular contractility: in one patient from 37% to 44%, in another from 34% to 51% in one and two month, respectively.
 Conclusions. Cardiomyopathy due to right ventricular pacing tends to occur instantaneously in the first years after pacemaker implantation, rather than slowly progressing over time. A wider paced QRS complex is an independent predictor of PICM. Biventricular pacing effectively eliminates the consequences of non-physiological right ventricular pacing, improves left ventricular systolic function.

Why does CRT work better in women?

Abstract Introduction It has been recently postulated that cardiac resynchronization therapy (CRT) might have a higher efficacy in women, with a greater reverse cardiac remodeling in this population. The reasons for these differences are not yet completely understood. We aimed to detect sex differences in the degree of ventricular asynchrony (VA) and mitral regurgitation (MR) in patients undergoing CRT implantation. Methods We analyzed baseline characteristics of a prospective international clinical trial that compared CRT response rate in a HF population with a comparable distribution of men and women (BIOWOMEN). A total of 408 patients were analyzed. The degree of mitral regurgitation and intra and inter-ventricular asynchrony was assessed by independent echocardiographers in a core lab. Inter-ventricular asynchrony was defined as an interventricular mechanical delay greater than 40ms and intra-ventricular asynchrony as differences greater than 50ms among regional pre-ejection periods. Multivariable logistic regression was performed using commercial data analysis software. Results As expected, ventricular asynchrony was dependent on QRS duration and the presence of LBBB (p<0.01). Baseline QRS duration was significantly shorter in women than men (155.85±19.0 in women vs 160.4±21.6, p=0.02). However, for a similar QRS duration, there were no differences in asynchrony parameters between the two groups (p=0.43; Figure 1). Female sex was associated with a significantly higher proportion of mitral regurgitation for a given QRS duration, which was independent of the etiology (p=0.05). Conclusions In our analysis, for a given QRS duration there was not a higher degree of asynchrony in women with HF. However, female sex was associated with a significantly higher proportion of mitral regurgitation for a given QRS duration irrespective of baseline HF etiology. Further investigations are needed to establish a possible link between these findings and better CRT outcomes in women. Funding Acknowledgement Type of funding sources: Private company. Main funding source(s): BIOTRONIK SE & Co. KG

Interventricular systolic asynchrony predicts prognosis in patients with systemic sclerosis-associated pulmonary arterial hypertension.

Pulmonary arterial hypertension (PAH) is a serious complication of SSc with high mortality. Interventricular systolic asynchrony (IVSA) is observed in PAH patients, but the effect of IVSA and its association with long-term mortality and clinical events in SSc-associated PAH are unclear. This study aimed to investigate the impact of IVSA on the prognosis of SSc-associated PAH. Between March 2010 and July 2018, a total of 60 consecutive patients with SSc-associated PAH were enrolled. The end point was a composite of all-cause mortality and clinical worsening. Asynchrony was assessed by colour-coded tissue Doppler imaging (TDI) echocardiography. The myocardial sustained systole curves (Sm) of the basal portion of the right ventricular (RV) free wall and left ventricular (LV) lateral wall were obtained. IVSA was defined as the time difference from the onset of the QRS complex to the end of Sm between LV and RV. Patients with greater IVSA time differences presented with advanced pulmonary vascular resistance (PVR). The IVSA time difference was an independent predictive factor (Hazard Ratio (HR) = 1.018, 95% CI: 1.005, 1.031, P =0.005) for the composite end point and was significantly associated with PVR (r = 0.399, R2=0.092, P =0.002). Kaplan-Meier survival curves showed that patients with greater IVSA had worse prognoses (log-rank P =0.001). In conclusion, IVSA analysed by colour-coded TDI echocardiography provided added value as a noninvasive, easy-to-use approach for assessing the prognosis of patients with SSc-associated PAH. A significant IVSA time difference identifies the subgroup of patients at high risk of a poor prognosis.

Point-of-Care Echocardiography: A Useful Tool for Assessing Complex Arrhythmias in the Pediatric Intensive Care Unit

To demonstrate that the analysis of the atrioventricular, intraventricular, and interventricular asynchrony by point-of-care ultrasound (POCUS) could be an alternative tool for assessing complex arrhythmias in pediatric patients with congenital heart diseases, mainly when an epicardial register or electrophysiology study is not available. Descriptive, retrospective case series study. The pediatric intensive care unit of a university-affiliated tertiary hospital in Spain. The authors included 12 patients with congenital heart disease younger than 18 years admitted to the authors' pediatric intensive care unit (PICU) from January 2018 to December 2019, with complex arrhythmias after surgery, managed by performing a bedside echocardiography when an electrophysiology test or epicardial auriculogram was unavailable. None. The authors included a total of 14 complex arrhythmias in 12 postsurgical patients in whom a comprehensive transthoracic electrocardiogram was not conclusive. The presence of atrioventricular, intraventricular, or interventricular asynchrony was assessed in standard echo views by performing M-mode and Doppler mitral inflow analysis, checking the heart motion. The final POCUS diagnoses were atrial flutter (n = 5), postsurgical atrioventricular block (n = 4), asynchrony induced by pacemaker (n = 2), junctional ectopic tachycardia (n = 1), nodal rhythm plus ventricular extrasystole (n = 1), and supraventricular tachycardia (n = 1). In all patients, regardless of the type of arrhythmia, detecting motion asynchrony was crucial for making the correct diagnosis. Offline cardiologist analysis of the POCUS scans showed full agreement. POCUS is a useful tool for initial diagnosis and management of complex arrhythmias in the PICU, mainly when epicardial auriculogram or electrophysiology studies are unavailable.

A case report of simultaneous His pacemaker implantation and atrioventricular junction ablation following unsuccessful treatment of atrial fibrillation

Atrial fibrillation can contribute to heart failure. Frequently, rhythm control is unachievable. Atrioventricular (AV) junction ablation and pacemaker implantation remain to be a therapeutic option for rate control in atrial fibrillation. Interventricular asynchrony is a potential downside of right ventricular pacing. However, cardiac resynchronization therapy and His pacing restore physiological activation sequences of the ventricles. The reported patient had undergone several interventions to cure atrial fibrillation without sufficient rhythm control and experienced deleterious effects of recurrent arrhythmias. Finally, we decided to ablate the AV junction simultaneously with the implantation of a His bundle pacemaker. Atrioventricular junction ablation had to be repeated following conduction recurrence. A left-sided transaortic approach was required to create a permanent effect and to avoid distal lesions. His pacing was not affected by the AV junction ablation at all. The pre-existing widened QRS was normalized by His pacing, the patient became free of any complaints with full restoration of exertion capability. His pacing has the potential to contribute to a revival of the 'ablate-and-pace' concept for incurable atrial fibrillation by restoring physiological ventricular activation, thereby overcoming the particular drawbacks of continuous ventricular pacing. Atrioventricular junction ablation simultaneously with the pacemaker implantation procedure is safe and feasible. His pacing is at least an alternative for cardiac resynchronization therapy. The implantation procedure is sometimes challenging.

Computational Analysis of Coronary Blood Flow: The Role of Asynchronous Pacing and Arrhythmias

In this work we present a one-dimensional (1D) mathematical model of the coronary circulation and use it to study the effects of arrhythmias on coronary blood flow (CBF). Hydrodynamical models are rarely used to study arrhythmias’ effects on CBF. Our model accounts for action potential duration, which updates the length of systole depending on the heart rate. It also includes dependency of stroke volume on heart rate, which is based on clinical data. We apply the new methodology to the computational evaluation of CBF during interventricular asynchrony due to cardiac pacing and some types of arrhythmias including tachycardia, bradycardia, long QT syndrome and premature ventricular contraction (bigeminy, trigeminy, quadrigeminy). We find that CBF can be significantly affected by arrhythmias. CBF at rest (60 bpm) is 26% lower in LCA and 22% lower in RCA for long QT syndrome. During bigeminy, trigeminy and quadrigeminy, respectively, CBF decreases by 28%, 19% and 14% with respect to a healthy case.

Evaluation of left and right ventricular systolic and diastolic electromechanical synchrony in older people: a population-based observational study.

It is unknown whether physiological ageing also goes along with electromechanical asynchrony of contraction. Aim of the study was to evaluate synchrony of contraction in older people with ("non-healthy") or without ("healthy") evidence for structural cardiac disease. In 547 persons (age 76.7+/-5.5 years, 306 male, 241 female) recruited from a population-based cohort of the ActiFE-Ulm study including a random sample of people >/=65 years old living in the region of Ulm, Germany, various PW- and TDI-Doppler based markers for asynchrony were obtained by echocardiography. Within a subgroup of 84 healthy subjects, at most minimal systolic and diastolic asynchrony was found. Concerning systolic asynchrony, similar observations were made within the non-healthy subgroup. However, extent of diastolic left ventricular intraventricular asynchrony and also - by tendency - diastolic interventricular asynchrony was increased in comparison to the healthy subgroup. To conclude, no evidence that physiological ageing might go along with relevant left or right ventricular systolic or diastolic electromechanical asynchrony was found in our study. Furthermore, our population-based data support the results from other clinical studies with rather selected cohorts that structural heart diseases might go along with increased diastolic asynchrony.

073_16753-K3 Super-Response to Cardiac Resynchronization Therapy in Patients With Dyssynchrony Cardiomyopathy

Left bundle-branch block (LBBB) is associated with intra and interventricular asynchrony, abnormal LV diastolic filling patterns and impairment of LV systolic function. So, there are patients with LBBB and LV systolic dysfunction without another etiology for heart failure, called “dyssynchrony

Integrative and quantitive evaluation of the efficacy of his bundle related pacing in comparison with conventional right ventricular pacing: a meta-analysis

BackgroundLong-term RVP could bring adverse problems to cardiac electro-mechanics and result in inter- and intra-ventricular asynchrony, impaired labor force, and aggravation of cardiac function. HBRP including direct His bundle pacing and para-His bundle pacing was regarded as a novel physiological pacing pattern to avoid devastating cardiac function. This synthetic study was conducted to integratively and quantitatively evaluate the efficacy of His bundle related pacing (HBRP) in comparison with conventional right ventricular pacing (RVP).MethodsPublished studies on comparison of left ventricular ejection fraction (LVEF), left ventricular end diastolic volume (LVEDV), left ventricular end systolic volume (LVESV), New York Heart Association (NYHA) class, inter-ventricular asynchrony, and QRS duration, etc. between HBRP and RVP were collected and for meta-analysis.ResultsHBRP showed higher LVEF (WMD = 3.9%, 95% CI: 1.6% – 6.1%), lower NYHA class (WMD = −0.5, 95% CI: -0.7 – -0.3), WMD of LVESV = −0.1 ml, 95% CI: -3.0 – 2.8 ml), less inter-ventricular asynchrony (WMD = −13.2 ms, 95% CI: -16.4 – -10.0 ms), and shorter QRS duration for long-term (WMD = −36.9 ms, 95% CI: -40.0 – -33.8 ms), however, no significant difference of ventricular volume (WMDLVEDV = −2.4 ml, 95% CI: -5.0 – 0.2 ml; WMDLVESV = −0.1 ml, 95% CI: -3.0 – 2.8 ml) compared to RVP.ConclusionsThe efficacy of HBRP was firstly verified by meta-analysis to date. Compared with RVP, HBRP markedly preserve LVEF, NYHA class, and QRS duration. However, it seemed to have less effect on ventricular volume.

Left ventricular remodeling in patients with right ventricular myocardial infarction

Aim . To study left ventricular (LV) remodeling, interventricular and intraventricular asynchrony in isolated inferior LV myocardial infarction (MI) or combined inferior LV MI with right ventricular (RV) MI. Material and methods. 57 patients with inferior LV MI with or without RV MI (n=57) were included in a 6-month prospective study. The patients were divided into 2 groups: Group 1 - patients with inferior LV MI (n=30); Group 2 - patients with inferior LV MI in combination with RV MI (n=27). Electrocardiography and echocardiography were performed in all patients at admission, on days 3, 30 and 180 after MI. Results. Significant signs of diastolic dysfunction (RV end-diastolic area 29.21±2.0 cm2) were found in group 2 on the third day after MI. A significant increase in the LV volume indices and diastolic sphericity index (from 0.54±0.02 to 0.59±0.03 units) and an increase in interventricular asynchrony (from 37.4±4.2 to 44.6±4.2 ms) were found in group 2 in 30 days after MI. Increasing tendency towards intraventricular and interventricular asynchrony, despite the absence of pathological LV remodeling, occurred in group 2 in 6 months after MI. Conclusion. Patients with RV MI have more pronounced maladaptive LV remodeling, intraventricular and interventricular asynchrony and greater LV diastolic dysfunction.

Physiological ventricular myocardial asynchrony

Tissue Doppler imaging (TDI) is one of the main methods for the quantification of synchronicity of ventricular myocardium motions. Thirty-two healthy volunteers (18 men and 14 women; mean age, 35.8 ± 11.0 years) with no evidence of cardiovascular disease found in their histories or during the standard clinical-instrumental examination were examined for the physiological ventricular asynchrony parameters determined by TDI. The proposed relative systolic and diastolic asynchrony parameters (the intraventricular and interventricular asynchrony indices calculated in eight segments at the basal and middle myocardial levels) and the conventional absolute parameters (the septal-lateral delay S-L, the QS, QE, T s SD, T E SD intervals) were determined and compared. The data on the determined range of normal values of the relative physiological myocardial asynchrony parameters in healthy individuals are cited. Greater systolic and diastolic asynchrony were revealed at the middle ventricular level compared to the basal level, as well as of diastolic versus systolic asynchrony, which is discussed from the standpoint of the model of the helical heart.

Cardiac asynchrony in Duchenne muscular dystrophy

Duchenne muscular dystrophy (DMD) is an inherited myogenic disorder due to mutations in the dystrophin gene on chromosome Xp21.1. Heart failure is a classical complication in this disease. Little data are available about systolic dyssynchrony in DMD. We sought to assess the prevalence of left ventricular dysfunction and systolic asynchrony in DMD patients using echocardiographic parameters. We performed electrocardiography and echocardiography for adult's patients with DMD. For systolic dyssynchrony assessment, echocardiography-Doppler was performed and completed by tissular Doppler imaging. 48 DMD were included in our study. Age ranged from 20 to 37years. QRS duration >120ms was present in 10 patients/48 and 1 patient disclosed a QRS duration >150ms. Left ventricular (LV) ejection fraction (EF) ranged from 10 to 62% with a median of 43%. Inter-ventricular asynchrony was found in 11.9% of patients with EF<35% and in 2.6% of patients with EF>35%. Intra-ventricular asynchrony was present in 6% of patients with EF<35%. We found a high prevalence of LV dysfunction in DMD. Systolic ventricular asynchrony seems frequent particularly in patients with EF<35%.

Left Ventricular Synchrony and Function in Pediatric Patients with Definitive Pacemakers

BackgroundChronic right ventricular pacing (RVP) induces a dyssynchronous contraction pattern, producing interventricular and intraventricular asynchrony. Many studies have shown the relationship of RVP with impaired left ventricular (LV) form and function.ObjectiveThe aim of this study was to evaluate LV synchrony and function in pediatric patients receiving RVP in comparison with those receiving LV pacing (LVP).MethodsLV systolic and diastolic function and synchrony were evaluated in 80 pediatric patients with either nonsurgical or postsurgical complete atrioventricular block, with pacing from either the RV endocardium (n = 40) or the LV epicardium (n = 40). Echocardiographic data obtained before pacemaker implantation, immediately after it, and at the end of a mean follow-up of 6.8 years were analyzed.ResultsLV diastolic function did not change in any patient during follow-up. LV systolic function was preserved in patients with LVP. However, in children with RVP the shortening fraction and ejection fraction decreased from medians of 41% ± 2.6% and 70% ± 6.9% before implantation to 32% ± 4.2% and 64% ± 2.5% (p < 0.0001 and p < 0.0001), respectively, at final follow-up. Interventricular mechanical delay was significantly larger with RVP (66 ± 13 ms) than with LVP (20 ± 8 ms). Similarly, the following parameters were significantly different in the two groups: LV mechanical delay (RVP: 69 ± 6 ms, LVP: 30 ± 11 ms, p < 0.0001); septal to lateral wall motion delay (RVP: 75 ± 19 ms, LVP: 42 ± 10 ms, p < 0.0001); and, septal to posterior wall motion delay (RVP: 127 ± 33 ms, LVP: 58 ± 17 ms, p < 0.0001).ConclusionCompared with RV endocardium, LV epicardium is an optimal site for pacing to preserve cardiac synchrony and function.

Left Ventricular Asynchrony in Patients with Right Bundle Branch Block and Normal Ejection Fraction

The role of right bundle branch block (RBBB) for the induction of left ventricular (LV) asynchrony is discussed controversially. The objective of this study was to assess presence and degree of LV asynchrony in patients with RBBB, left bundle branch block (LBBB), or left anterior hemiblock (LAH) and normal LV function. We included 15 patients with RBBB, 13 patients with RBBB and concomitant LAH, 10 patients with pure LBBB, and 100 healthy controls into this study. All patients had normal LV function. Interventricular asynchrony was assessed as the difference of the right and LV ejection delay. Intraventricular delay was obtained by tissue synchronicity imaging-guided tissue Doppler imaging measurement. Interventricular and left intraventricular asynchrony were linked to the presence of an LBBB. No left intraventricular asynchrony was noted during pure RBBB; interventricular delays were negative (aortic flow preceding pulmonary flow) in the presence of RBBB. In patients with normal LV function, intraventricular asynchrony depends on the presence of an LBBB and interventricular asynchrony is inversed in the presence of RBBB.

A Study of Mechanical Optimization Strategy for Cardiac Resynchronization Therapy Based on an Electromechanical Model

An optimal electrode position and interventricular (VV) delay in cardiac resynchronization therapy (CRT) improves its success. However, the precise quantification of cardiac dyssynchrony and magnitude of resynchronization achieved by biventricular (BiV) pacing therapy with mechanical optimization strategies based on computational models remain scant. The maximum circumferential uniformity ratio estimate (CURE) was used here as mechanical optimization index, which was automatically computed for 6 different electrode positions based on a three-dimensional electromechanical canine model of heart failure (HF) caused by complete left bundle branch block (CLBBB). VV delay timing was adjusted accordingly. The heart excitation propagation was simulated with a monodomain model. The quantification of mechanical intra- and interventricular asynchrony was then investigated with eight-node isoparametric element method. The results showed that (i) the optimal pacing location from maximal CURE of 0.8516 was found at the left ventricle (LV) lateral wall near the equator site with a VV delay of 60 ms, in accordance with current clinical studies, (ii) compared with electrical optimization strategy of E RMS, the LV synchronous contraction and the hemodynamics improved more with mechanical optimization strategy. Therefore, measures of mechanical dyssynchrony improve the sensitivity and specificity of predicting responders more. The model was subject to validation in future clinical studies.

Interventricular asynchrony in Chronic Thrombo Embolic Pulmonary Hypertension recovers after pulmonary endarterectomy: role of right ventricular wall stress

Interventricular mechanical asynchrony is a characteristic of right ventricular (RV) pressure overload. Myocardial wall stress may play a key role. Wall stress reduction by an intervention may provide evidence for this role.

Successful reduction of intraventricular asynchrony is associated with superior response to cardiac resynchronization therapy

BackgroundCardiac resynchronization therapy (CRT) is generally associated with a low to moderate increase of the left ventricular ejection fraction (LVEF). In some patients, however, LVEF improves remarkably and reaches near-normal values. The aim of the present study was to further characterize these so called 'super-responders' with a special focus on the extent of intra- and interventricular asynchrony before and after device implantation compared to average responders.Methods37 consecutive patients who underwent CRT device implantation according to current guidelines were included in the study. Patients were examined by echocardiography before, one day after and six months after device implantation. Pre-defined criterion for superior response to CRT was an LVEF increase > 15% after six months.ResultsAt follow-up, eight patients (21.6%) were identified as super-responders. There were no significant differences regarding age, gender, prevalence of ischemic heart disease and LVEF between average and super-responders at baseline. After six months, LVEF had significantly increased from 26.7% ± 5.7% to 33.1% ± 7.9% (p < 0.001) in average and from 24.0% ± 6.7% to 50.3% ± 7.4% (p < 0.001) in super-responders. Both groups showed a significant reduction of QRS duration as well as LV end-diastolic and -systolic volumes under CRT. At baseline, the interventricular mechanical delay (IVMD) was 53.7 ± 20.9 ms in average and 56.9 ± 22.4 ms in super-responders - representing a similar extent of interventricular asynchrony in both groups (p = 0.713). CRT significantly reduced the IVMD to 20.3 ± 15.7 (p < 0.001) in average and to 19.8 ± 15.9 ms (p = 0.013) in super-responders with no difference between both groups (p = 0.858). As a marker for intraventricular asynchrony, we assessed the longest intraventricular delay between six basal LV segments. At baseline, there was no difference between average (86.2 ± 30.5 ms) and super-responders (78.8 ± 23.6 ms, p = 0.528). CRT significantly reduced the longest intraventricular delay in both groups - with a significant difference between average (66.2 ± 36.2 ms) and super-responders (32.5 ± 18.3 ms, p = 0.022). Multivariate logistic regression analysis identified the longest intraventricular delay one day after device implantation as an independent predictor of superior response to CRT (p = 0.038).ConclusionsA significant reduction of the longest intraventricular delay correlates with superior response to CRT.

Ventricular Mechanical Asynchrony in Patients with Different Degrees of Systolic Dysfunction: Results from AVE Registry by the Italian Society of Cardiovascular Echography (SIEC)

The aim of the study was to compare the prevalence of interventricular and intraventricular asynchrony in patients with different degrees of left ventricular (LV) dysfunction. We enrolled 182 patients (male 79%, mean age 64 +/- 11 years) with LV ejection fraction (EF) < 50% and identified two groups: Group A (n = 79) with mild-to-moderate LV dysfunction (EF between 36% and 49%) and Group B (n = 103) with severe dysfunction (EF <or= 35%). An echocardiogram was performed in all patients and a delay longer than 40 msec in the time difference between the aortic and pulmonary preejection intervals was considered as an index of interventricular asynchrony. The electromechanical delays were assessed by pulsed tissue Doppler technique. A time difference between the earliest and the latest segment greater than 40 msec was considered the cutoff for intraventricular asynchrony. The sum of asynchrony was calculated by adding to the LV intraventricular delay the delay between the lateral basal right ventricular segment and the most delayed LV basal segment. The prevalence of interventricular asynchrony was lower among Group A patients (19.8% vs. 37.9%; P = 0.007) while the prevalence of intraventricular asynchrony did not differ between groups (32.9% vs. 44% in Group A and Group B respectively; P = 0.18). The sum of asynchrony (cutoff >102 msec) did not differ between groups either (29.9% vs. 35.9%; P = 0.39). The prevalence of intraventricular asynchrony is independent of the LV systolic dysfunction severity. This could indicate the potential role of cardiac resynchronization therapy in patients with mild-moderate systolic dysfunction.