Right Ventricular Dyssynchrony Research Articles

Myocardial work across different etiologies of right ventricular dysfunction and healthy controls.

Evaluating right ventricular (RV) function remains a challenge. Recently, novel echocardiographic assessment of RV myocardial work (RVMW) by non-invasive pressure-strain loops was proposed. This enables evaluation of right ventriculoarterial coupling and quantifies RV dyssynchrony and post-systolic shortening. We aimed to assess RVMW in patients with different etiologies of RV dysfunction and healthy controls. We investigated healthy controls (n=17), patients with severe functional tricuspid regurgitation (FTR; n=22), and patients with precapillary pulmonary hypertension (PCPH; n=20). Echocardiography and right heart catheterization were performed to assess 1) RV global constructive work (RVGCW; work needed for systolic myocardial shortening and isovolumic relaxation), 2) RV global wasted work (RVGWW; myocardial shortening following pulmonic valve closure), and 3) RV global work efficiency (RVGWE; describes the relation between RV constructive and wasted work). RVGCW correlated with invasive RV stroke work index (r=0.66, P<0.001) and increased in tandem with higher afterload, i.e., was low in healthy controls (454±73 mmHg%), moderate in patients with FTR (687±203 mmHg%), and highest among patients with PCPH (881±255 mmHg%). RVGWE was lower and RVGWW was higher in patients with FTR (86±8% and 91 mmHg% [53-140]) or PCPH (86±10% and 110 mmHg% [66-159]) as compared with healthy controls (96±3% and 10 mmHg%). RVMW by echocardiography provides a promising index of RV function to discriminate between patients with RV volume or pressure overload. The prognostic value of this measure needs to be settled in future studies.

How to assess and treat right ventricular electromechanical dyssynchrony in post-repair tetralogy of Fallot: insights from imaging, invasive studies, and computational modelling.

Right bundle branch block (RBBB) and resulting right ventricular (RV) electromechanical discoordination are thought to play a role in the disease process of subpulmonary RV dysfunction that frequently occur post-repair tetralogy of Fallot (ToF). We sought to describe this disease entity, the role of pulmonary re-valvulation, and the potential added value of RV cardiac resynchronization therapy (RV-CRT). Two patients with repaired ToF, complete RBBB, pulmonary regurgitation, and significantly decreased RV function underwent echocardiography, cardiac magnetic resonance, and an invasive study to evaluate the potential for RV-CRT as part of the management strategy. The data were used to personalize the CircAdapt model of the human heart and circulation. Resulting Digital Twins were analysed to quantify the relative effects of RV pressure and volume overload and to predict the effect of RV-CRT. Echocardiography showed components of a classic RV dyssynchrony pattern which could be reversed by RV-CRT during invasive study and resulted in acute improvement in RV systolic function. The Digital Twins confirmed a contribution of electromechanical RV dyssynchrony to RV dysfunction and suggested improvement of RV contraction efficiency after RV-CRT. The one patient who underwent successful permanent RV-CRT as part of the pulmonary re-valvulation procedure carried improvements that were in line with the predictions based on his Digital Twin. An integrative diagnostic approach to RV dysfunction, including the construction of Digital Twins may help to identify candidates for RV-CRT as part of the lifetime management of ToF and similar congenital heart lesions.

Pressure overload is associated with right ventricular dyssynchrony in heart failure with reduced ejection fraction.

The determinants and relevance of right ventricular (RV) mechanical dyssynchrony in heart failure with reduced ejection fraction (HFrEF) are poorly understood. We hypothesized that increased afterload may adversely affect the synchrony of RV contraction. A total of 148 patients with HFrEF and 36 controls underwent echocardiography, right heart catheterization, and gated single-photon emission computed tomography to measure RV chamber volumes and mechanical dyssynchrony (phase standard deviation of systolic displacement timing). Exams were repeated after preload (N=135) and afterload (N=15) modulation. Patients with HFrEF showed higher RV dyssynchrony compared with controls (40.6±17.5° vs. 27.8±9.1°, P<0.001). The magnitude of RV dyssynchrony in HFrEF correlated with larger RV and left ventricular (LV) volumes, lower RV ejection fraction (RVEF) and LV ejection fraction, reduced intrinsic contractility, increased heart rate, higher pulmonary artery (PA) load, and impaired RV-PA coupling (all P≤0.01). Low RVEF was the strongest predictor of RV dyssynchrony. Left bundle branch block (BBB) was associated with greater RV dyssynchrony than right BBB, regardless of QRS duration. RV afterload reduction by sildenafil improved RV dyssynchrony (P=0.004), whereas preload change with passive leg raise had modest effect. Patients in the highest tertiles of RV dyssynchrony had an increased risk of adverse clinical events compared with those in the lower tertile [T2/T3 vs. T1: hazard ratio 1.98 (95% confidence interval 1.20-3.24), P=0.007]. RV dyssynchrony is associated with RV remodelling, dysfunction, adverse haemodynamics, and greater risk for adverse clinical events. RV dyssynchrony is mitigated by acute RV afterload reduction and could be a potential therapeutic target to improve RV performance in HFrEF.

Prognostic value of right ventricular dyssynchrony in adults with repaired tetralogy of Fallot

ObjectiveResidual sequelae after surgical repair of tetralogy of Fallot (rTOF) affect clinical outcome. We investigated the prognostic impact of right ventricular (RV) dyssynchrony in adults with rTOF years after the...

Ventricular dyssynchrony late after the Fontan operation is associated with decreased survival

BackgroundVentricular dyssynchrony and its relationship to clinical outcomes is not well characterized in patients following Fontan palliation. MethodsSingle-center retrospective analysis of cardiac magnetic resonance (CMR) imaging of patients with a Fontan circulation and an age-matched healthy comparison cohort as controls. Feature tracking was performed on all slices of a ventricular short-axis cine stack. Circumferential and radial strain, strain rate, and displacement were measured; and multiple dyssynchrony metrics were calculated based on timing of these measurements (including standard deviation of time-to-peak, maximum opposing wall delay, and maximum base-to-apex delay). Primary endpoint was a composite measure including time to death, heart transplant or heart transplant listing (D/HTx). ResultsA total of 503 cases (15 y; IQR 10, 21) and 42 controls (16 y; IQR 11, 20) were analyzed. Compared to controls, Fontan patients had increased dyssynchrony metrics, longer QRS duration, larger ventricular volumes, and worse systolic function. Dyssynchrony metrics were higher in patients with right ventricular (RV) or mixed morphology compared to those with LV morphology. At median follow-up of 4.3 years, 11% had D/HTx. Multiple risk factors for D/HTx were identified, including RV morphology, ventricular dilation, dysfunction, QRS prolongation, and dyssynchrony. Ventricular dilation and RV morphology were independently associated with D/HTx. ConclusionsCompared to control LVs, single right and mixed morphology ventricles in the Fontan circulation exhibit a higher degree of mechanical dyssynchrony as evaluated by CMR-FT. Dyssynchrony indices correlate with ventricular size and function and are associated with death or need for heart transplantation. These data add to the growing understanding regarding factors that can be used to risk-stratify patients with the Fontan circulation.

Right ventricular cardiac resynchronization therapy in patients with right ventricular conduction delay and heart failure

Right ventricular cardiac resynchronization therapy in patients with right ventricular conduction delay and heart failure

Determinants of impaired coupling of right ventricle to hemodynamic load in advanced HFrEF

Abstract Background The mechanisms and consequnces of impaired right ventricular (RV) dysfunction and impaired RV-pulmonary artery (PA) coupling in advanced heart failure (HF) poorely understood. Purpose To compare RV-PA coupling parameters in patients with advanced HFrEF, PAH and in controls to ellucidate determinants and prognostic impact of RV-PA uncoupling in HFrEF. Methods 260 pacients with advanced HF (NYHA 3.0±0.5, 40% CAD, LVEF: 23±10%, 87% males, BMI: 28±4.5 kg/m2, BNP: 1238±982 pg/ml), 39 controls and 21 PAH patients underwent lab tests, ecocardiography, right heart catheterisation and equilibrium gated blood pool SPECT to precisely measure cardiac volumes. RV End-systolic elastance (Ees) and Effective arterial elastance (Ea) were calculated by single beat method. Patients were longitudinally followed for occurrence of adverse outcome (urgent Tx, LVAD or death without Tx/LVAD). Results PAH patients had higher PA pressures and more dilated RV than HFrEF and controls. Despite of that, RV-PA coupling, reflected by Ees/Ea ratio, was more profoundly reduced in HFrEF than in PAH (Figure). While RV contractility (Ees) was augmented by increased afterload in PAH, such augmentation was absent in HFrEF. At follow-up (median 258; 53–763 days), 69% of HFrEF subjects experienced adverse event (17% death, 24% urgent HTx, 28% LVAD). In HFrEF, RV-PA coupling was strongly predictive od adverse outcome, more than RV EF%, RV EDV or RV Ees. The strongest predictors of reduced RV Ees/Ea ratio in HFrEF were in descending order: RV EF, RV EDV, PA systolic/systemic systolic pressure ratio (PAs/SBP), PAWP, heart rate, PA compliance, RA mean pressure, PA mean pressure, BNP level, SBP, PAs, Tri Reg grade, Non-CAD etiology of HF, Mi Reg grade, PVR, RV dyssynchrony, absence of ACEi/ARB/S-V (GLM model, all p&amp;lt;0.001). RV Ees/Ea ratio correlated with PAs/SBP ratio, that reflects systolic ventricular interdependence. Invasive PAs/SBP predicted outcome and closely correlated with non-invasive estimation of PAs/SBP. Conclusion Despite having less PH and smaller RV, RV coupling is more impaired in HFrEF than in PAH due to absence of RV contractility enhancement. Higher RV volume, heart rate, tricuspid regurgitation, lower PA compliance, higher PAWP and systolic ventricular interdependence (PAs/SBP) are main determinants of RV PA decoupling in HFrEF. Elevated PA systolic pressure but low systemic BP (high PAs/SBP ratio) is associated with poor RV-PA coupling and prognosis. Funding Acknowledgement Type of funding sources: Public grant(s) – National budget only. Main funding source(s): AZV NU20-02-00052, AZV NU21-02-00402

Right Ventricular Dyssynchrony in Patients With Chronic Thromboembolic Pulmonary Hypertension and Pulmonary Arterial Hypertension.

Chronic thromboembolic pulmonary hypertension (CTEPH) and pulmonary arterial hypertension (PAH) are characterized by elevated pulmonary arterial pressure resulting in right heart failure. Right ventricular (RV) dyssynchrony may be associated with early-stage RV dysfunction; however, the differences in RV dyssynchrony between CTEPH and PAH and the factors contributing to RV dyssynchrony remain unclear.Methods and Results: Forty-four patients (CTEPH, 26; PAH, 18) were enrolled in this study. RV dyssynchrony was assessed by determining the standard deviation of the intervals from the peak QRS to peak systolic strain for 6 segments of the RV free and septal wall by using 2-dimensional speckle-tracking echocardiography (RV-6SD). The RV-6SD, pulmonary hemodynamics, echocardiographic findings, and patient demographics in CTEPH and PAH patients were compared and their correlations with RV-6SD were investigated. CTEPH patients were older and had significantly higher pulse pressure of the pulmonary artery (PP), tricuspid valve regurgitation pressure gradient, and RV-6SD, and lower pulmonary arterial compliance (PAC), despite showing comparable pulmonary arterial pressures. Age-adjusted multiple logistic analysis showed that RV-6SD and PAC were predictors of CTEPH rather than PAH. RV-SD6 was positively correlated with PP and RV dimension and negatively correlated with PAC. CTEPH patients showed more evident RV dyssynchrony than PAH patients. Low PAC and a widened PP may delay RV free wall motion and cause RV dyssynchrony.

A Comprehensive Functional Analysis in Patients after Atrial Switch Surgery.

Background Long-term course after atrial switch operation is determined by increasing right ventricular (RV) insufficiency. The aim of our study was to investigate subtle functional parameters by invasive measurements with conductance technique and noninvasive examinations with cardiac magnetic resonance imaging (CMR). Methods We used invasive (pressure–volume loops under baseline conditions and dobutamine) and noninvasive techniques (CMR with feature tracking [FT] method) to evaluate RV function. All patients had cardiopulmonary exercise testing (CPET). Results From 2011 to 2013, 16 patients aged 28.2 ± 7.3 (22–50) years after atrial switch surgery (87.5% Senning and 12.5% Mustard) were enrolled in this prospective study. All patients were in New York Heart Association (NYHA) class I to II and presented mean peak oxygen consumption of 30.1 ± 5.7 (22.7–45.5) mL/kg/min. CMR-derived end-diastolic volume was 110 ± 22 (78–156) mL/m 2 and RV ejection fraction 41 ± 8% (25–52%). CMR-FT revealed lower global systolic longitudinal, radial, and circumferential strain for the systemic RV compared with the subpulmonary left ventricle. End-systolic elastance (Ees) was overall reduced (compared with data from the literature) and showed significant increase under dobutamine (0.80 ± 0.44 to 1.89 ± 0.72 mm Hg/mL, p ≤ 0.001), whereas end-diastolic elastance (Eed) was not significantly influenced (0.11 ± 0.70 to 0.13 ± 0.15 mm Hg/mL, p = 0.454). We found no relevant relationship between load-independent conductance indices and strain or CPET parameters. Conductance analysis revealed significant mechanical dyssynchrony, higher during diastole (mean 30 ± 4% baseline, 24 ± 6% dobutamine) than during systole (mean 17 ± 6% baseline, 19 ± 7% dobutamine). Conclusions Functional assessment of a deteriorating systemic RV remains demanding. Conductance indices as well as the CMR-derived strain parameters showed overall reduced values, but a significant relationship was not present (including CPET). Our conductance analysis revealed intraventricular and predominantly diastolic RV dyssynchrony.

The influence of increased venous return on right ventricular dyssynchrony during acute and sustained hypoxaemia.

What is the central question of this study? Right ventricular dyssynchrony is a marker of function that is elevated in healthy individuals exposed to acute hypoxia, but does it remain elevated during sustained exposure to high altitude hypoxia, and can it be normalised by augmenting venous return? What is the main finding and its importance? For the first time it is demonstrated that (i) increasing venous return in acute hypoxia restores the synchrony of right ventricular contraction and (ii) dyssynchrony is evident after acclimatisation to high altitude, and remains sensitive to changes in venous return. Therefore, the interpretation of right ventricular dyssynchrony requires consideration the prevailing haemodynamic state. Regional heterogeneity in timing of right ventricular (RV) contraction (RV dyssynchrony; RVD) occurs when pulmonary artery systolic pressure (PASP) is increased during acute hypoxia. Interestingly, RVD is not observed during exercise, a stimulus that increases both PASP and venous return. Therefore, we hypothesised that RVD in healthy humans is sensitive to changes in venous return, and examined whether (i) increasing venous return in acute hypoxia lowers RVD and (ii) if RVD is further exaggerated in sustained hypoxia, given increased PASP is accompanied by decreased ventricular filling at high altitude. RVD, PASP and right ventricular end-diastolic area (RVEDA) were assessed using transthoracic two-dimensional and speckle-tracking echocardiography during acute normobaric hypoxia ( =0.12) and sustained exposure (5-10days) to hypobaric hypoxia (3800m). Venous return was augmented with lower body positive pressure at sea level (LBPP; +10mmHg) and saline infusion at high altitude. PASP was increased in acute hypoxia (20±6 vs. 28±7, P<0.001) concomitant to an increase in RVD (18±7 vs. 38±10, P<0.001); however, the addition of LBPP during hypoxia decreased RVD (38±0 vs. 26±10, P<0.001). Sustained hypoxia increased PASP (20±4 vs. 26±5, P=0.008) and decreased RVEDA (24±4 vs. 21±2, P=0.042), with RVD augmented (14±5 vs. 31±12, P=0.001). Saline infusion increased RVEDA (21±2 vs. 23±3, P=0.008) and reduced RVD (31±12 vs. 20±9, P=0.001). In summary, an increase in PASP secondary to acute and sustained exposure to hypoxia augments RVD, which can be at least partly reduced via increased venous return.

Acute effects of intravenous pimobendan administration in dog models of chronic precapillary pulmonary hypertension

IntroductionPulmonary hypertension (PH) is a progressive and potentially life-threatening disease. Several drugs are used for the treatment of dogs with precapillary PH. Pimobendan is an inotropic drug with phosphodiesterase 3 inhibitory and calcium-sensitizing effects. Pimobendan administration improved right ventricular (RV) function and lowered pulmonary arterial pressure in some human patients with precapillary PH. However, the efficacy of pimobendan in dogs with precapillary PH is unknown. Animals, material, and methodsAn implantable port device was percutaneously placed in the cranial vena cava of five laboratory beagles. Chronic embolic precapillary PH was induced via the repeated injection of microspheres every 1–2 days. Microsphere injection was continued until systolic pulmonary arterial pressure reached 50 mmHg. Right heart catheterization and echocardiography were performed at baseline and after injections of placebo and pimobendan (0.15 mg/kg). ResultsRepeated injections of microspheres caused an increase in pulmonary vascular resistance, a decrease in stroke volume, RV dilation, left ventricular (LV) and RV dysfunction, and RV dyssynchrony as assessed using echocardiography. Compared with placebo, pimobendan improved LV and RV function based on the LV Tei index from 0.48 to 0.38 (p=0.002) and the RV Tei index from 0.76 to 0.61 (p=0.008), as well as the stroke volume index from 29.4 to 36.7 ml/m2 (p=0.012), respectively. ConclusionsIn dog models of chronic PH, intravenous pimobendan effectively improved RV and LV function and increased stroke volume. However, pimobendan administration did not decrease pulmonary arterial pressure or produce hypotension.

Preliminary Study of Right Ventricular Dyssynchrony Under High-Altitude Exposure: Determinants and Impacts.

The aims of this study were to explore the effect of high-altitude (HA) exposure on the incidence, determinants, and impacts of right ventricular dyssynchrony (RVD). In our study, 108 healthy young men were enrolled, and physiological and echocardiographic variables were recorded at both sea level and 4,100 m. By using two-dimensional speckle-tracking echocardiography, RVD was evaluated by calculating the R–R interval-corrected standard deviation of the time-to-peak systolic strain for the four mid-basal RV segments (RVSD4) and defined by RVSD4 > 18.7 ms. After HA exposure, RVSD4 was significantly increased, and the incidence of RVD was approximately 32.4%. Subjects with RVD showed lower oxygen saturation (SaO2) and RV global longitudinal strain and higher systolic pulmonary artery pressure than those without RVD. Moreover, myocardial acceleration during isovolumic contraction was increased in all subjects and those without RVD, but not in those with RVD. Multivariate logistic regression revealed that SaO2 is an independent determinant of RVD at HA (odds ratio: 0.72, 95% CI: 0.56–0.92; P = 0.009). However, the mean pulmonary artery pressure was linearly correlated with the magnitude of RVD in the presence of Notch. No changes were found in RV fractional area change, tricuspid annular motion, or tricuspid s’ velocity between subjects with and without RVD. Collectively, we demonstrated for the first time that HA exposure could induce RVD in healthy subjects, which may be mainly attributed to the decline in SaO2 as well as RV overload; the incidence of RVD was associated with reduced RV regional function and blunted myocardial acceleration.

Equilibrium radionuclide angiography compared with tissue doppler imaging for detection of right ventricular dyssynchrony and prediction of acute response to cardiac resynchronization therapy.

Objective:The aim of this study was to compare tissue doppler imaging (TDI) and equilibrium radionuclide angiography (ERNA) for detection of right ventricular (RV) dyssynchrony and prediction of the acute response to cardiac resynchronization therapy (CRT).Methods:This study was approved by the local ethics committee of Huai’an First People's Hospital. Patient consent was not provided due to the use of completely anonymous images from which the individual could not be identified in this study. Thirty-three patients with nonischemic dilated cardiomyopathy underwent both TDI and ERNA before and within 48 hour after CRT implantation. RV dyssynchrony was measured with TDI using the difference in time to peak systolic velocity between the RV free wall and ventricular septum (RV-T). With ERNA, the standard of RV mean phase angle and RV phase standard deviation (RVmPA% and RVPSD%) were assessed.Results:Moderate positive correlations were observed among baseline RVmPA%, RVPSD% and RV-T (r = 0.689 and 0.716, P < .001). Twenty patients (61%) with a reduction of at least 15% in LV end-systolic volume were categorized as acute responders after CRT. Responders showed significant reduction in RVmPA% and RVPSD% after CRT (53.60 ± 4.15% to 43.95 ± 6.88% and 14.00 ± 2.41% to 10.40 ± 1.67%, P < .05), whereas RV-T remained unchanged (50.10 ± 10.28 ms to 49.25 ± 13.64ms, NS). Receiver operating characteristic curve showed that the cut-off value of RV-T was 48.5ms, yielding 65% sensitivity and 77% specificity to predict acute respond to CRT. The cut-off value of RVmPA% was 49.5%, yielding 85% sensitivity and 85% specificity and the cut-off value of RVPSD% was 11.5%, yielding 85% sensitivity and 92% specificity.Conclusion:ERNA might be an appropriate alternative to TDI for assessment of RV dyssynchrony. Either RVmPA% or RVPSD% was highly predictive for acute response to CRT.

The impact of right bundle branch block on right ventricular size and function assessed by three-dimensional speckle-tracking echocardiography.

To determine the influence of right bundle branch block (RBBB) on right ventricular (RV) size and function, we investigated the association between complete RBBB (CRBBB) and RV volume, function, and dyssynchrony by three-dimensional echocardiography. In this retrospective, cross-sectional study, 103 consecutive patients with adequate three-dimensional echocardiographic images were divided into the CRBBB, middle-range QRS, and narrow QRS group. RV volumetric and functional data were compared between the three groups. Among the 103 patients (44.8 ± 18.7years, 50 men), the CRBBB group comprised 26 (25%) patients and the middle-range QRS group comprised 48 (47%). The CRBBB group showed a significant contraction delay in the RV inlet free wall and outflow tract; larger RV end-diastolic and systolic volume index (RV-EDVI, RV-ESVI); and lower RV systolic function. On dividing the CRBBB patients into two (with or without mechanical dyssynchrony), those with RV dyssynchrony showed larger RV-EDVI (121 ± 45 vs. 85 ± 25 mL/m2, P = 0.019) and RV-ESVI (93 ± 42 vs. 56 ± 20 mL/m2, P = 0.009) and smaller RV ejection fraction (24 ± 11 and 34 ± 11%, P = 0.026) than those without RV dyssynchrony. RV dyssynchrony in CRBBB patients might have an adverse effect on RV volume and function. Three-dimensional speckle-tracking echocardiography could provide additional and beneficial data during assessment of RV dyssynchrony.

Right ventricular function and dyssynchrony measured by echocardiography in dogs with precapillary pulmonary hypertension

IntroductionAssessment of the right ventricular (RV) function by echocardiography is important in dogs with pulmonary hypertension (PH). Few reports are available on RV function and dyssynchrony in dogs, especially in the context of precapillary PH. AnimalsThe study included 79 client-owned dogs: 25 dogs with precapillary PH and 54 control dogs. MethodsDogs with precapillary PH were prospectively enrolled between December 2013 and February 2017. The echocardiographic indices of RV function, including RV strain and the dyssynchrony index by speckle-tracking echocardiography, were measured. Multivariate analysis was used to determine independent predictors of the RV dyssynchrony index. ResultsDogs with precapillary PH showed RV dilation, hypertrophy and right atrial dilation. Impaired echocardiographic indices of RV function, including RV strain, were observed. In addition, RV dyssynchrony occurred in dogs with precapillary PH. Multivariate analysis revealed that tricuspid regurgitation velocity and RV dilation were independent predictors of the RV dyssynchrony index. ConclusionsEchocardiographic RV function indices are impaired in dogs with precapillary PH. In addition, RV dilation and elevated systolic pulmonary arterial pressure estimated by echocardiography are associated with RV dyssynchrony.

Effects of cardiac resynchronization therapy on right ventricular function during rest and exercise, as assessed by radionuclide angiography, and on NT-proBNP levels

AimWe carried out this study to investigate mid-term effects of cardiac resynchronization therapy (CRT) on right ventricular (RV) function and neurohormonal response, expressed by N-terminal pro-brain natriuretic peptide (NT-proBNP), in heart failure patients stratified by baseline RV ejection fraction (RVEF). Methods and ResultsThirty-six patients with nonischemic dilated cardiomyopathy underwent technetium-99m radionuclide angiography with bicycle exercise immediately after CRT implantation (during spontaneous rhythm and after CRT activation) and 3 months later. Plasma NT proBNP was assessed before implantation and after 3 months. At baseline, RVEF was impaired (≤35%) in 14 patients, preserved (>35%) in 22. At 3 months, RVEF improved during rest and exercise (P = .02) in patients with impaired RV function, while remaining unchanged in patients with preserved RV function. Rest and exercise RV dyssynchrony decreased in both groups at follow-up (P < .05). A similar mid-term improvement in left ventricular (LV) function and NT-proBNP was observed in patients with impaired and preserved RVEF. In the former, the decrease in NT-proBNP correlated with the improvements both in LV and RV dyssynchrony and functions. ConclusionCRT may improve RV performance, during rest and exercise, and neurohormonal response in heart failure patients with nonischemic dilated cardiomyopathy and baseline RV dysfunction. RV dysfunction should not be considered per se a primary criterion for excluding candidacy to CRT.

Higher ultrafiltration rate is associated with right ventricular mechanical dispersion.

Objective:Ultrafiltration rate is one of the major determinants of adverse outcomes in patients undergoing hemodialysis (HD) therapy. Previous studies have focused on the impact of HD on right ventricular (RV) peak strain values. However, the influence of HD on the temporal characteristics of deformation has not been reported yet. The aim of the present study was to evaluate the impact of high ultrafiltration rate (HUR) on RV mechanical dyssynchrony.Methods:Echocardiographic images focused on the RV and left ventricle (LV) were obtained from 60 patients (49.2±17.3 years, 22 female) before and after HD. Patients were divided into two groups according to ultrafiltration rate. Changes in echocardiographic parameters with HD were examined. Two-dimensional speckle-tracking strain analysis was used to assess deformation. Mechanical dispersion was measured as the standard deviation of time to peak longitudinal strain of six segments for RV and 18 segments for LV.Results:The average ultrafiltrated volume and ultrafiltration rate were 3000.1±1007.9 mL and 11.4±2.9 mL/kg/h, respectively. Global longitudinal strain (GLS) of the RV and LV decreased after HD in both groups. A significant difference was observed in RV mechanical dispersion with HD for patients in the high ultrafiltration group. A mild statistically insignificant increase in LV mechanical dispersion was also observed after HD.Conclusion:HUR has a substantial impact on LV and RV GLS and RV dyssynchrony. Ultrafiltration rates and volumes should be kept as low as possible to achieve hemodynamic stability and tolerability.

Right ventricular dyssynchrony and functional capacity before and after percutaneous balloon mitral valvuloplasty in patients with mitral stenosis: Determinants and clinical impact.

We aimed to investigate the utility of right ventricular (RV) dyssynchrony to assess functional capacity utilizing 6-minute walking test distance (6MWTD) and to measure brain natriuretic peptide levels (BNP) in patients with mitral stenosis (MS) and to study its value to predict adverse outcome following percutaneous balloon mitral valvuloplasty (PBMV). A total of 108 patients with moderate to severe MS (26.5±7.5years) were included in this study. All were candidates for PBMV. RV strain curves were obtained using two-dimensional speckle-tracking echocardiography, and standard deviation (SD) of 4 segments without RV apex (-SD4) was also assessed. 6MWT and BNP were before and after 12months following PBMV. RV-SD4 was significantly prolonged in patients with MS compared with controls (P<0.001). Patients with 6MWTD ≤300m had a significantly increased RV-SD4 (P<0.001) and had higher BNP values (P<0.03) compared with those with 6MWTD >300m. RV-SD4 showed a strong correlation with 6MWT and BNP level. RV-SD4 was the strongest independent predictor of adverse outcome following PBMV (P<0.0001). Receiver operating characteristic analysis showed that RV-SD4 ≥24ms was the cutoff value which predicts the adverse outcome following PBMV. A considerable improvement of mean 6MWT with significant reduction of BNP levels after 12months of follow-up (P<0.001) in subjects with RV dyssynchrony <24ms. Right ventricular dyssynchrony is a useful predictor of functional status, as assessed with 6MWTD and BNP level in patients with MS. Furthermore, it might be considered as an independent predictor of adverse outcome following PMBV.

Right ventricular dyssynchrony during hypoxic breathing but not during exercise in healthy subjects: a speckle tracking echocardiography study.

What is the central question of this study? Right ventricular dyssynchrony in severe pulmonary hypertension is associated with a poor prognosis. However, it has recently been observed in patients with lung or connective tissue disease and pulmonary artery pressure at the upper limits of normal. The mechanisms of right ventricular dyssynchrony in pulmonary hypertension remain uncertain. What is the main finding and its importance? Acute hypoxic breathing, but not normoxic exercise, induces an increase in right ventricular dyssynchrony detected by speckle tracking echocardiography in healthy subjects. These results add new insights into the determinants of right ventricular dyssynchrony, suggesting a role for systemic factors added to afterload in the pathophysiology of right ventricular inhomogeneity of contraction. Pulmonary hypertension (PH) has been shown to be associated with regional inhomogeneity (or dyssynchrony) of right ventricular (RV) contraction. Right ventricular dyssynchrony is an independent predictor of decreased survival in advanced PH, but has also been reported in patients with only mildly elevated pulmonary artery pressure (PAP). The mechanisms of RV dyssynchrony in PH remain uncertain. Our aim was to evaluate RV regional function in healthy subjects during acute hypoxia and during exercise. Seventeen healthy subjects (24±6years) underwent a speckle tracking echocardiography of the RV at rest in normoxia and every 15min during a 60min exposure to hypoxic breathing ( 12%). Ten of the subjects also underwent an incremental cycle ergometry in normoxia to 100W, with the same echocardiographic measurements. Dyssynchrony was measured as the SD of the times to peak systolic strain of the four basal and mid RV segments corrected for the heart rate (RV-SD4). RV-SD4 increased during hypoxia from 12±7 to 22±11ms in spite of mild increases in mean PAP (mPAP) from 15±2 to 20±2mmHg and pulmonary vascular resistance (PVR) from 1.18±0.15 to 1.4±0.15 Wood units (WU). During exercise RV-SD4 did not significantly change (from 12±6ms to 14±6ms), while mPAP increased to 25±2mmHg and PVR was unchanged. These data show that in healthy subjects, RV contraction is inhomogeneous in hypoxia but not during exercise. Since PAP increases more during exercise, RV dyssynchrony in hypoxia may be explained by a combination of mechanical (RV afterload) and systemic (hypoxia) factors.

Quantification of Right Ventricular Electromechanical Dyssynchrony in Relation to Right Ventricular Function and Clinical Outcomes in Children with Repaired Tetralogy of Fallot

Electromechanical dyssynchrony occurs ubiquitously following tetralogy of Fallot (TOF) repair, manifesting electrically as a wide QRS duration and mechanically as a right-sided septal/apical flash. Early septal activation and prestretch of the right ventricular (RV) basal lateral wall followed by its postsystolic shortening contributes to inefficient RV mechanics. However, a right-sided septal flash is a dichotomous finding, and the severity of RV dyssynchrony as a continuous spectrum in relationship to RV dysfunction and clinical outcomes in patients with repaired TOF has not been studied. The aim of this study was to quantify the severity of electromechanical dyssynchrony in relation to RV remodeling and clinical outcomes in a pediatric cohort following TOF repair. A retrospective analysis was performed in 81 children with RV volume loading after TOF repair, aged 13.6±2.9years, and compared with 50 matched control subjects. Patients had higher RV basal-lateral prestretch and postsystolic strain amplitude and duration, RV mechanical dispersion, and basal lateral-septal wall delay compared with control subjects (P<.001 for all). All intra-RV dyssynchrony timing parameters were associated with reduced cardiac magnetic resonance-derived RV ejection fraction and/or echocardiography-derived RV longitudinal strain. Prestretch duration as a percentage of total shortening time and RV basal lateral-to-midseptal delay were independently associated with RV dysfunction. Postsystolic strain amplitude was higher in patients with ventricular arrhythmias compared with arrhythmia-free patients (7.8% [4.2%-13%] vs 2.0% [0%-12.5%], P=.03). RV prestretch duration, postsystolic strain, and RV lateral-septal delay quantify RV electromechanical dyssynchrony severity and reflect the underlying pathophysiology. The prestretch duration percentage and RV basal lateral-to-midseptal delay were independently associated with RV dysfunction, potentially providing a clinical tool to quantify RV electromechanical dyssynchrony.