Evaluation of right ventricular strain in two separate cohorts with precapillary pulmonary hypertension.

Evaluation for right ventricular (RV) dysfunction is an important part of risk assessment in care of patients with pulmonary hypertension (PH) as it is associated with morbidity and mortality. Echocardiography provides a widely available and acceptable method to assess RV function. RV global longitudinal strain (RVGLS), a measure of longitudinal shortening of RV deep muscle fibers obtained by two-dimensional echocardiography, was previously shown to predict short-term mortality in patients with PH. The purpose of the current study was to assess the performance of RVGLS in predicting 1-year outcomes in PH. We retrospectively identified 83 subjects with precapillary PH and then enrolled 50 consecutive prevalent pulmonary arterial hypertension (PAH) subjects into a prospective validation cohort. Death as well as combined morbidity and mortality events at 1 year were assessed as outcomes. In the retrospective cohort, 84% of patients had PAH and the overall 1-year mortality rate was 16%. Less negative RVGLS was marginally better than tricuspid annular plane systolic excursion (TAPSE) as a predictor for death. However, in the prospective cohort, 1-year mortality was only 2%, and RVGLS was not predictive of death or a combined morbidity and mortality outcome. This study supports that RV strain and TAPSE have similar 1-year outcome predictions but highlights that low TAPSE or less negative RV strain measures are often false-positive in a cohort with low baseline mortality risk. While RV failure is considered the final common pathway for disease progression in PAH, echocardiographic measures of RV function may be less informative of risk in serial follow-up of treated PAH patients.

Left Ventricular Strain from Myocardial Perfusion PET Imaging: Method Development and Comparison to 2-Dimensional Echocardiography.

This study aimed to develop a measure of longitudinal, radial, and circumferential myocardial strain at rest and regadenoson during pharmacologic stress using 82Rb PET electrocardiography-gated myocardial perfusion imaging (MPI). Methods: We retrospectively identified 80 patients who underwent rest and regadenoson-stress CT attenuation-corrected 82Rb PET and had a standard resting transthoracic echocardiogram (TTE) with global longitudinal strain (GLS) analysis within 3 mo. A method was developed to compute longitudinal, radial, and circumferential strain from PET MPI at stress and rest. PET MPI-derived strain and left ventricular function were compared with resting TTE measures as the clinical reference standard. Interobserver agreement of PET MPI strain and left ventricular ejection fraction processing was reported. Results: Longitudinal strain assessed with resting TTE GLS showed good correlation with PET MPI at stress (r = 0.68, P < 0.001) and rest (r = 0.58, P < 0.001). Resting TTE GLS also correlated with PET MPI radial strain at stress (r = -0.70, P < 0.001) and rest (r = -0.59, P < 0.001) and circumferential strain at stress (r = 0.67, P < 0.001) and rest (r = 0.69, P < 0.001). The left ventricular ejection fraction showed good correlation between resting TTE and PET MPI at stress (r = 0.83, P < 0.001) and rest (r = 0.80, P < 0.001). Bland-Altman analysis indicated positive bias of TTE GLS compared with PET MPI longitudinal strain at stress (mean difference = 5.1%, 95% CI = [-2.5, 12.7]) and rest (mean difference = 4.2%, 95% CI = [-4.3, 12.8]). Reproducibility of PET MPI longitudinal strain showed good agreement at stress (concordance correlation coefficient = 0.73, P < 0.001) and rest (concordance correlation coefficient = 0.74, P < 0.001), with Bland-Altman analysis showing a small bias in the longitudinal direction at stress (mean difference = -0.2%) and rest (mean difference = -1.0%). Conclusion: Strain measured with PET MPI using an automated technique correlated well with resting GLS strain obtained by TTE, and the measure is reproducible. Strain from PET MPI should be investigated further to establish reference ranges and assess its value in routine clinical practice.

Arrhythmogenic Right Ventricular Cardiomyopathy in an Endurance Athlete Presenting with Ventricular Tachycardia and Normal Right Ventricular Function.

Arrhythmogenic right ventricular cardiomyopathy, a genetically inherited disease that results in fibrofatty replacement of normal cardiac myocytes, has been associated with sudden cardiac death in athletes. Long-term participation in endurance exercise hastens the development of both the arrhythmic and structural arrhythmogenic right ventricular cardiomyopathy phenotypes. We describe the unusual case of a 34-year-old, symptomatic, female endurance athlete who had arrhythmogenic right ventricular cardiomyopathy in the presence of a structurally normal right ventricle. Clinicians should be aware of this infrequent presentation when evaluating athletic patients who have ventricular arrhythmias and normal findings on cardiac imaging studies.

Superior Mesenteric Arterial Flow Pattern is Associated with Major Adverse Events in Adults with Fontan Circulation.

Factors contributing to the failure of Fontan circulation in adults are poorly understood. Reduced superior mesenteric arterial (SMA) flow has been identified in pediatric Fontan patients with protein-losing enteropathy. SMA flow has not been profiled in an adult Fontan population and its association with adverse events is unknown. We aimed to examine associations between SMA flow patterns and adverse events in adult Fontan patients. We performed a retrospective review of adult Fontan patients who underwent echocardiograms between 2008 and 2014. SMA Doppler data included peak systolic and end-diastolic velocity and velocity time integral (VTI). Systolic/diastolic (S/D) ratio and resistive index were calculated. The relationship between SMA flow parameters and major adverse events (death or transplantation) was examined using proportional hazard Cox regression analyses. Kaplan-Meyer analysis was conducted to construct survival curve of patients with and without adverse events. 91 post-Fontan adult patients (76 % systemic left ventricle, 20 % atriopulmonary Fontan, mean age 27.9 years) were analyzed. Adverse events occurred in nine patients (death = 4, transplant = 5). When compared with the non-event group, the event group had increased end-diastolic velocity [hazard ratio (HR) 1.5, 95 % confidence interval (CI) 1.1-1.8; p = 0.002], increased systolic VTI (HR 1.5, 95 % CI 1.1-2.2, p = 0.02), increased diastolic VTI (HR 1.7, 95 % CI 1.2-2.4, p = 0.004), decreased S/D velocity ratio (HR 0.32, 95 % CI 0.14-0.71, p = 0.006), decreased S/D VTI ratio (HR 0.76, 95 % CI 0.61-0.97, p = 0.02), and decreased resistive index (HR 0.29, 95 % CI 0.14-0.60, p = 0.0007). Increased end-diastolic velocity and VTI in mesenteric arterial flow, with lower systolic/diastolic ratio and resistive index, were associated with death and need for heart transplant in adult Fontan patients. The mesenteric hyperemic flow was also associated with clinical signs of portal venous outflow obstruction, suggesting the presence of vasodilatory state in end-stage adult Fontan circulation.

The Right Ventricular Function After Left Ventricular Assist Device (RVF-LVAD) study: rationale and preliminary results.

AIMS: Despite improved outcomes and lower right ventricular failure (RVF) rates with continuous-flow left ventricular assist devices (LVADs), RVF still occurs in 20-40% of LVAD recipients and leads to worse clinical and patient-centred outcomes and higher utilization of healthcare resources. Preoperative quantification of RV function with echocardiography has only recently been considered for RVF prediction, and RV mechanics have not been prospectively evaluated. METHODS AND RESULTS: In this single-centre prospective cohort study, we plan to enroll a total of 120 LVAD candidates to evaluate standard and mechanics-based echocardiographic measures of RV function, obtained within 7 days of planned LVAD surgery, for prediction of (i) RVF within 90 days; (ii) quality of life (QoL) at 90 days; and (iii) RV function recovery at 90 days post-LVAD. Our primary hypothesis is that an RV echocardiographic score will predict RVF with clinically relevant discrimination (C >0.85) and positive and negative predictive values (>80%). Our secondary hypothesis is that the RV score will predict QoL and RV recovery by 90 days. We expect that RV mechanics will provide incremental prognostic information for these outcomes. The preliminary results of an interim analysis are encouraging. CONCLUSION: The results of this study may help improve LVAD outcomes and reduce resource utilization by facilitating shared decision-making and selection for LVAD implantation, provide insights into RV function recovery, and potentially inform reassessment of LVAD timing in patients at high risk for RVF.

The prognostic value of standardized reference values for speckle-tracking global longitudinal strain in hypertrophic cardiomyopathy.

Speckle-tracking left ventricular global longitudinal strain (GLS) assessment may provide substantial prognostic information for hypertrophic cardiomyopathy (HCM) patients. Reference values for GLS have been recently published. We aimed to evaluate the prognostic value of standardized reference values for GLS in HCM patients. An analysis of HCM clinic patients who underwent GLS was performed. GLS was defined as normal (more negative or equal to -16%) and abnormal (less negative than -16%) based on recently published reference values. Patients were followed for a composite of events including heart failure hospitalization, sustained ventricular arrhythmia, and all-cause death. The power of GLS to predict outcomes was assessed relative to traditional clinical and echocardiographic variables present in HCM. 79 HCM patients were followed for a median of 22 months (interquartile range 9-30 months) after imaging. During follow-up, 15 patients (19%) met the primary outcome. Abnormal GLS was the only echocardiographic variable independently predictive of the primary outcome [multivariate Hazard ratio 5.05 (95% confidence interval 1.09-23.4, p = 0.038)]. When combined with traditional clinical variables, abnormal GLS remained independently predictive of the primary outcome [multivariate Hazard ratio 5.31 (95 % confidence interval 1.18-24, p = 0.030)]. In a model including the strongest clinical and echocardiographic predictors of the primary outcome, abnormal GLS demonstrated significant incremental benefit for risk stratification [net reclassification improvement 0.75 (95 % confidence interval 0.21-1.23, p < 0.0001)]. Abnormal GLS is an independent predictor of adverse outcomes in HCM patients. Standardized use of GLS may provide significant incremental value over traditional variables for risk stratification.

Bad company: supracristal VSD presenting with ruptured sinus of valsalva aneurysm. a case presentation with echocardiographic depiction and an analysis of contemporary literature.

Supracristal ventricular septal defect (SCVSD), a defect of the infundibular portion of the interventricular septum just below the right aortic cusp, occurs more frequently in Eastern Asian populations. SCVSD may be complicated by right sinus of Valsalva aneurysm (SoVA). We present the case of a 26-year-old male of Korean descent with a history of a childhood murmur who was referred to our institution for progressive heart failure symptoms. He was diagnosed with SCVSD and ruptured right SoVA based on history, physical exam, and echocardiography including three-dimensional transesophageal echocardiography with reconstructed surgical views. The patient underwent SCVSD closure, SoVA excision, and valve-sparing aortic root replacement. We reviewed the echocardiography literature regarding SCVSD and SoVA, and analyzed contemporary literature of SoVA and its relationship with SCVSD. We conclude that a higher prevalence of ruptured SoVA in Eastern Asians is likely related to a higher prevalence of underlying SCVSD in this population.

Correlates of tricuspid regurgitation as determined by 3D echocardiography: pulmonary arterial pressure, ventricle geometry, annular dilatation, and papillary muscle displacement.

BACKGROUND: While it is understood that annular dilatation contributes to tricuspid regurgitation (TR), other factors are less clear. The geometry of the right ventricle (RV) and left ventricle (LV) may alter tricuspid annulus size and papillary muscle (PM) positions leading to TR. METHODS AND RESULTS: Three-dimensional echocardiographic images were obtained at Emory University Hospital using a GE Vivid 7 ultrasound system. End-diastolic area was used to classify ventricle geometry: control (n=21), isolated RV dilatation (n=17), isolated LV dilatation (n=13), and both RV and LV dilatation (n=13). GE EchoPAC was used to measure annulus area and position of the PM tips. Patients with RV dilatation had significant (P≤ 0.05) displacement of all PMs apically and the septal PM and posterior PM away from the center of the RV toward the LV. Patients with LV dilatation had significant (P≤0.05) apical displacement of the anterior PM. Pulmonary arterial pressure (r=0.66), annulus area (r=0.51), apical displacement of the anterior PM (r=0.26), posterior PM (r=0.49), and septal PM (r=0.40), lateral displacement of the septal PM (r=0.37) and posterior PM (r=0.40), and tenting area and height (r=0.54, 0.49), were significantly (P≤0.05) correlated to the grade of TR. Ventricle classification (r=0.46) and RV end-diastolic area (r=0.48) also were correlated with the grade of TR. A regression analysis found ventricle classification (P=0.001), pulmonary arterial pressure (P≤0.001) annulus area (P=0.027), and apical displacement of the anterior PM (P=0.061) to be associated with the grade of TR. CONCLUSIONS: Alterations in ventricular geometry can lead to TR by altering both tricuspid annulus size and PM position. Understanding these geometric interactions with the aim of correcting pathological alterations of the tricuspid valve apparatus may lead to more robust repairs.

Right ventricular function with standard and speckle-tracking echocardiography and clinical events in adults with D-transposition of the great arteries post atrial switch.

BACKGROUND: The prognostic value of deformation parameters of the systemic right ventricle in adults with D-transposition of the great arteries and prior atrial switch has not been reported. METHODS: Sixty-four adults with D-transposition of the great arteries and prior atrial switch (mean age, 29 ± 6 years; 22 women; mean right ventricular [RV] fractional area change, 22.9 ± 7.5%; 31 with pacemakers at baseline) and no histories of heart failure or ventricular tachycardia were prospectively evaluated. Global longitudinal strain (GS), global systolic strain rate (GSRs), and global early diastolic strain rate (GSRe) of the right ventricle were measured using speckle tracking from apical views and compared with standard parameters of RV function (fractional area change, tricuspid annular plane systolic excursion, tissue Doppler velocities, and isovolumic acceleration) for association with and potential prediction of clinical events, defined as incident stage C heart failure or ventricular tachycardia. RESULTS: Baseline RV GS, GSRs, and GSRe were -12.5 ± 3.0%, -0.59 ± 0.14 sec(-1), and 0.68 ± 0.22 sec(-1), respectively. After a median of 2.4 years (interquartile range, 1.5-4.1 years), 12 patients (19%) presented with clinical events (heart failure in 11 patients, ventricular tachycardia in one patient). In Cox models, RV GS had the strongest association with clinical events (hazard ratio [HR] per 1%, 1.35; 95% confidence interval [CI], 1.14-1.58; P < .001), followed by GSRs (HR per 0.01 sec(-1), 1.06; 95% CI, 1.02-1.11; P = .006), GSRe (HR per -0.01 sec(-1), 1.04; 95% CI, 1.00-1.07; P = .031), and fractional area change (HR per -1%, 1.08; 95% CI, 1.00-1.17; P = .047). Other measures of RV function were not significantly associated with risk for events. In receiver operating characteristic analysis, RV GS ≥ -10% optimally predicted future events (C = 0.83; 95% CI, 0.71-0.91; P < .001). CONCLUSIONS: Reduced longitudinal GS of the systemic right ventricle is associated with increased risk for clinical events among patients with D-transposition of the great arteries and prior atrial switch.

Left ventricular function improves after pulmonary valve replacement in patients with previous right ventricular outflow tract reconstruction and biventricular dysfunction.

Congenital heart defects that have a component of right ventricular outflow tract obstruction, such as tetralogy of Fallot, are frequently palliated in childhood by disruption of the pulmonary valve. Although this can provide an initial improvement in quality of life, these patients are often left with severe pulmonary valve insufficiency. Over time, this insufficiency can lead to enlargement of the right ventricle and to the deterioration of right ventricular systolic and diastolic function. Pulmonary valve replacement in these patients decreases right ventricular volume overload and improves right ventricular performance. To date, few studies have examined the effects of pulmonary valve replacement on left ventricular function in patients with biventricular dysfunction. We sought to perform such an evaluation.Records of adult patients who had undergone pulmonary valve replacement from January 2003 through November 2006 were analyzed retrospectively. We reviewed preoperative and postoperative echocardiograms and calculated left ventricular function in 38 patients.In the entire cohort, the mean left ventricular ejection fraction increased by a mean of 0.07 after pulmonary valve replacement, which was a statistically significant change (P < 0.01). In patients with preoperative ejection fractions of less than 0.50, mean ejection fractions increased by 0.10.We conclude that pulmonary valve replacement in patients with biventricular dysfunction arising from severe pulmonary insufficiency and right ventricular enlargement can improve left ventricular function. Prospective studies are needed to verify this finding.

Percutaneous closure of a left atrial appendage pseudoaneurysm.

Atrial dissections and pseudoaneurysms are rare complications of cardiac surgery. The authors describe the case of a patient after mitral valve replacement who presented with a left atrial appendage pseudoaneurysm. This case represents the first known closure of an atrial pseudoaneurysm with a percutaneous septal occluder device.

Right ventricular function in adult patients with Eisenmenger physiology: insights from quantitative echocardiography.

BACKGROUND: The favorable outcomes of Eisenmenger syndrome (ES) relative to other forms of pulmonary arterial hypertension (PAH) have been partially attributed to a unique adaptation of the right ventricle (RV). However, conventional measures of RV function may not adequately express this adaptation. METHODS: We studied 23 patients with ES (age 43 ± 17 years, 16 women, pulmonary artery systolic pressure [PASP] 93 ± 26 mmHg), 25 patients with PAH (age 44 ± 13 years, 17 women, PASP 92 ± 19 mmHg), and 25 subjects without known structural disease (age 45 ± 16 years, 17 women). We evaluated long- and short-axis function of the RV with two-dimensional strain and anatomical M-mode echocardiography, respectively. RESULTS: Long-axis function of the RV was comparable between patients with ES and PAH although depressed relative to controls (global strain, -15.6 ± 4.7, -14.9 ± 4.3, and -22.4 ± 2.8%, respectively, P < 0.001; global RV systolic strain rate, -0.77 ± 0.26, -0.84 ± 0.24, and -1.11 ± 0.21 1/sec, respectively, P < 0.001). However, short-axis RV function was significantly better in patients with ES versus those with PAH and preserved relative to controls (RV fractional shortening by anatomical M-mode, median [interquartile range], 21%[14-33%], 14%[10-16%], and 26%[22-36%], respectively, P = 0.002 for ES vs. PAH, P = 0.09 for ES vs. controls). This differential was not reflected in conventional measures of RV function (fractional area change, 32 ± 10 vs. 29 ± 8% in ES and PAH, respectively, P = 0.26). CONCLUSION: In patients with ES, the RV is characterized by preserved short-axis function, despite a depressed long-axis function. Thus, conventional assessment of RV function might not be suitable for patients with ES.

Late pulmonary valve replacement in congenital heart disease patients without original congenital pulmonary valve pathology.

Many congenital heart defects with pulmonary valve pathology are repaired or palliated in childhood. It is anticipated that these patients will need subsequent pulmonary valve replacement due to the pulmonary regurgitation or right ventricular dilation/failure that results from their original operation. Interestingly, some patients with prior congenital heart surgery and no congenital pulmonary valve pathology require pulmonary valve replacement in adulthood. The current study analyzed this subset of patients. The pediatric and adult congenital cardiac surgical databases at a large academic center were reviewed from 2001 to 2008 for pulmonary valve replacements. Patients without congenital pulmonary valve disease were identified. Preoperative, operative, and postoperative data were analyzed. Between 2001 and 2008, five patients with congenital heart disease but no pulmonary valve pathology underwent late pulmonary valve replacement. The initial congenital diagnoses were coarctation/ventricular septal defect (n = 3), complete atrioventricular septal defect (n = 1), and anomalous left coronary artery from the pulmonary artery (PA) (n = 1). All five patients had undergone main PA manipulation during their previous operations. Four of these patients had received PA banding and debanding, and one had received a Takeuchi tunnel repair and revision. All the patients underwent pulmonary valve replacement secondary to pulmonary regurgitation and right ventricular dilation. The average time from the last previous operation to the time of pulmonary valve replacement was 20.8 +/- 9.1 years. Bioprosthetic valves were used for all the pulmonary valve replacements, and there were no mortalities. Patients who have undergone previous PA manipulation, regardless whether congenital pulmonary pathology is present, may be at risk for pulmonary valve replacement in adulthood. This report describes five cases of patients with a history of congenital heart surgery but no congenital pulmonary valve pathology who required pulmonary valve replacement due to the consequences of prolonged pulmonary regurgitation. Although pulmonary regurgitation may be well tolerated for many years, it is further evidence for the importance of close follow-up assessment and monitoring of young adults with congenital heart disease.

Pulmonary arterial hypertension in patients with prior atrial switch procedure for d-transposition of great arteries (dTGA).

UNLABELLED: Pulmonary arterial hypertension (PAH) is an uncommon complication of atrial switch repair (Mustard or Senning) for d-transposition of the great arteries (dTGA), often difficult to diagnose by trans-thoracic echocardiography. This patient population is unique in that heart failure and elevated filling pressures are common after atrial switch repairs. Most studies evaluating the use of PAH therapies have excluded this group of patients. METHODS: Our echocardiography database was reviewed for patients with a diagnosis of dTGA status post-atrial switch operation treated with pulmonary vasodilator therapy (monotherapy or combination). RESULTS: Six patients (2 male, 4 female) were identified from 104 patients (67% male). Mean age at atrial switch was 22.1 months; mean age of PAH diagnosis was 29.3 years. Functional class improved from a baseline mean of 3.3 to 1.8 on treatment (p=0.001). No adverse events were associated with treatment. 3 of 4 patients initially referred for heart-lung transplant no longer require transplantation. CONCLUSIONS: PAH is a late complication of the atrial switch procedure for dTGA, affecting 5.7% of our dTGA atrial switch population, with a higher incidence in female patients. In this cohort, pulmonary arterial vasodilator therapy was well tolerated and improved functional status.

Octopus papillary muscle associated with a left lateral accessory pathway.

Left ventricular papillary muscle abnormalities are rare malformations. They have been related to significant mitral valve dysfunction and left ventricular midcavitary obstruction. We report our experience with a young adult who presented with palpitations. An echocardiogram on the patient showed an "octopus-like" left ventricular papillary muscle. Subsequent electrophysiologic testing showed evidence of supraventricular tachycardia via a left lateral accessory pathway associated with the abnormal insertion of the papillary muscle attachments.

Myocardial deformation imaging of the systemic right ventricle by two-dimensional strain echocardiography in patients with d-transposition of the great arteries.

INTRODUCTION: Functional assessment of the systemic right ventricle is often problematic in patients with Dtransposition of the great arteries (D-TGA) due to altered ventricular geometry. The clinical applicability of myocardial deformation imaging by two-dimensional strain (2DS) echocardiography in this setting is still under investigation. METHODS: We evaluated 27 patients with D-TGA (age 30 +/- 6 years, 9 female, 11 with paced rhythm) by standard and 2DS echocardiography; 27 outpatients (age 29 +/- 10 years, 15 female) without structural heart disease served as controls. High-resolution two-dimensional grayscale images were analyzed offline. Global values of peak strain (GS), systolic strain rate (GSRs), and early diastolic strain rate (GSRe) of the systemic ventricle, as well as the systemic ejection fraction (EF), were recorded from apical 4-chamber views. Intraobserver reproducibility was assessed by random-order repeat analysis. RESULTS: Global indices of myocardial deformation (GS, GSRs, GSRe) in the systemic right ventricle were reliably obtained in all 27 patients with D-TGA, and tracking was optimal in 159/162 segments (>98%). Mean GS in patients with D-TGA was -13.2 +/- 3.8% vs. -20.6 +/- 2.6% in controls, p<0.001; mean GSRs -0.59 +/- 0.16 /s vs. -1.10 +/- 0.19 /s, p<0.001; and mean GSRe 0.68 +/- 0.21 /s vs. 1.34 +/- 0.31 /s, p<0.001. Mean systemic EF by single-plane modified Simpson was 37 +/- 11% in patients with D-TGA vs. 60 +/- 7% in controls, p<0.001. GSRs exhibited the highest discriminative value between D-TGA patients and controls. The mean absolute percent error for GS, GSRs, GSRe, and systemic EF in D-TGA patients was 6.9% (p<0.05 vs. EF), 8.9%, 12.3%, 13.1%, respectively. CONCLUSIONS: Myocardial deformation parameters can be reliably obtained by 2DS echocardiography in patients with D-TGA. Deformation indices of the systemic right ventricle appear to be highly reproducible, and may provide a sensitive means to detect both systolic and diastolic abnormalities in patients with D-TGA.

Evaluation of right intraventricular dyssynchrony by two-dimensional strain echocardiography in patients with pulmonary arterial hypertension.

BACKGROUND: Right ventricular (RV) function has major prognostic implications for patients with pulmonary arterial hypertension (PAH). Intraventricular dyssynchrony might play an important role in RV dysfunction in these patients. METHODS: Thirty-six patients with PAH without right bundle branch block (mean age 44 +/- 14 yr, 24 women) and 39 controls (mean age 43 +/- 18 yr, 26 women) were evaluated. Global and segmental RV longitudinal deformation parameters were recorded by 2-dimensional strain echocardiography from apical 4-chamber views using a 6-segment RV model. The standard deviation of the heart rate-corrected intervals from QRS onset to peak strain for the 6 segments (RV-SD(6)) was used to quantify right intraventricular dyssynchrony. RESULTS: RV-SD(6) was significantly higher in patients with PAH compared with controls (63 +/- 21 vs 25 +/- 15ms, P < .001). Dyssynchrony in patients with PAH was found to derive mainly from delayed contraction of the basal and mid RV free wall. In patients with PAH, RV-SD(6) was strongly correlated with RV fractional area change (beta = -.519, P = .002), RV myocardial performance index (beta = .427, P = .009), and RV global strain (beta = .512, P = .002); in models controlling for RV systolic pressure, RV size, and QRS duration, RV-SD(6) was still an independent predictor of RV fractional area change (beta = -.426, P = .005) and RV global strain (beta = .358, P = .031). RV function was significantly worse in the subgroup of patients with PAH (n = 25) with RV-SD(6) > 55 ms (the upper 95% limit in controls). CONCLUSION: Right intraventricular dyssynchrony, as quantified by 2-dimensional strain echocardiography, is prevalent in PAH and is associated with more pronounced RV dysfunction. The clinical implications of these findings remain to be determined in follow-up studies.