Range of ventricular dimensions and function by steady-state free precession cine MRI in repaired tetralogy of Fallot: Right ventricular outflow tract patch vs. conduit repair

The effects of pregnancy in subjects with repaired tetralogy of Fallot

BACKGROUND

Previous reports reveal inconsistent findings of right ventricular (RV) changes following pregnancy in subjects with repaired tetralogy of Fallot (rTOF).

METHODS

A two-center, retrospective cohort study which included women with rTOF who completed pregnancy that were matched to nulliparous women with rTOF by age at the time of baseline cardiac magnetic resonance (CMR), RV ejection fraction (RVEF), and indexed RV end-diastolic volume (RVEDVi). Pre-pregnancy and postpartum cardiac magnetic resonance (CMR) were analyzed and compared to sequential CMR of nulliparous subjects with rTOF.

RESULTS

Thirty-six women with rTOF who completed pregnancy were matched to 72 nulliparous women with rTOF. Over a mean period of 3.1 years for the pregnancy group and 2.7 years for the comparison group, there was no significant change in the RVEDVi, RVEF, RV mass, pulmonary regurgitation severity, left ventricular (LV) volumes, LV ejection fraction (LVEF), or LV mass when comparing the baseline CMR and the follow-up CMR in either of the groups. There was a slight increase in RV indexed end-systolic volume (RVESVi) when comparing the baseline CMR and the follow-up CMR in the pregnancy group (68.93, SD 23.34 ml/m2 at baseline vs. 72.97, SD 25.24 mL/m2 at follow-up, P = .028). Using a mixed effects model for CMR parameters change over time; when adjusted for time between baseline and follow-up CMR there was no significant difference in rate of change between the pregnancy and comparison groups.

CONCLUSIONS

Most ventricular remodeling parameters measured by CMR did not significantly change in subjects with rTOF who completed pregnancy or in nulliparous subjects with rTOF. In the pregnancy group, RVESVi is larger in those individuals who have undergone pregnancy without a significant change in ventricular function. These patients should be followed longitudinally to determine the long-term ventricular and clinical effects of pregnancy.

Cine MRI-derived radiomics features indicate hemodynamic changes in the pulmonary artery

Although cine MRI-derived radiomics features in the cardiac blood pool have been used to represent cardiac function and motion, the clinical relevance of radiomics features in the great vessels is still unknown. The aim of the present study was to test the hypothesis that cine MRI-derived radiomics features of the pulmonary artery (PA) can represent hemodynamic abnormalities in pulmonary hypertension (PH). With the approval of the institutional review board (IRB), 50 PH patients (21 males, 36-89 years old, diagnosed with right heart catheterization [RHC]) and 23 healthy volunteers (14 males, 26-80 years old) were retrospectively enrolled in this study. All participants underwent cardiac 4D flow and cine MRI (25 retrospective phases) at the right ventricular (RV) outflow tract (RVOT). A total of 93 radiomics features were extracted from RVOT cine images through a fixed size region of interest (ROI) at the proximal part of the PA. The peak values of the 6 first order features were different between the PH patients and controls. 4D flow-derived mean velocity in PA was related to 'Kurtosis' (r = 0.452,), 'Range' (r = 0.426), 'Autocorrelation' (r = 0.407), 'Joint Average' (r = 0.459), 'Sum Average' (r = 0.459), 'High Gray Level Emphasis' (r = 0.41), 'Large Dependence High Gray Level Emphasis' (r = 0.44), 'High Gray Level Run Emphasis' (r = 0.422), 'Gray Level Variance' (r = 0.419), 'High Gray Level Zone Emphasis' (r = 0.451), and 'Small Area High Gray Level Emphasis' (r = 0.415). Mean RV pressure was related to 'Inverse Variance' (r = 0.43) and 'Run Percentage' (r = 0.403). All p values < 0.05. Cine MRI-derived PA radiomics features have the potential to serve as novel imaging biomarkers for representing hemodynamic changes in pulmonary circulation.

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

BACKGROUND

Ventricular dyssynchrony and its relationship to clinical outcomes is not well characterized in patients following Fontan palliation.

METHODS

Single-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).

RESULTS

A 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.

CONCLUSIONS

Compared 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 Heart Remodeling After Pulmonary Valve Replacement in Patients With Pulmonary Atresia or Critical Stenosis With Intact Ventricular Septum

Background Patients with pulmonary atresia or critical pulmonary stenosis with intact ventricular septum (PA/IVS) and biventricular circulation may require pulmonary valve replacement (PVR). Right ventricular (RV) remodeling after PVR is well described in tetralogy of Fallot (TOF); we sought to investigate RV changes in PA/IVS using cardiac magnetic resonance imaging. Methods and Results A retrospective cohort of patients with PA/IVS who underwent PVR at Boston Children's Hospital from 1995 to 2021 with cardiac magnetic resonance imaging before and after PVR was matched 1:3 with patients with TOF by age at PVR. Median regression modeling was performed with post-PVR indexed RV end-diastolic volume as the primary outcome. A total of 20 patients with PA/IVS (cases) were matched with 60 patients with TOF (controls), with median age at PVR of 14 years. Pre-PVR indexed RV end-diastolic volume was similar between groups; cases had higher RV ejection fraction (51.4% versus 48.6%; P=0.03). Pre-PVR RV free wall and left ventricular (LV) longitudinal strain were similar, although LV midcavity circumferential strain was decreased in cases (-15.6 versus -17.1; P=0.001). At a median of 2 years after PVR, indexed RV end-diastolic volume was similarly reduced; cases continued to have higher RV ejection fraction (52.3% versus 46.9%; P=0.007) with less reduction in RV mass (Δ4.5 versus 9.6 g/m2; P=0.004). Post-PVR, RV and LV longitudinal strain remained unchanged, and LV circumferential strain was similar, although lower in cases. Conclusions Compared with patients with TOF, patients with PA/IVS demonstrate similar RV remodeling after PVR, with lower reduction in RV mass and comparatively higher RV ejection fraction. Although no differences were detected in peak systolic RV or LV strain values, further investigation of diastolic parameters is needed.

Society for Cardiovascular Magnetic Resonance/European Society of Cardiovascular Imaging/American Society of Echocardiography/Society for Pediatric Radiology/North American Society for Cardiovascular Imaging Guidelines for the use of cardiovascular magnetic resonance in pediatric congenital and acquired heart disease : Endorsed by The American Heart Association

Cardiovascular magnetic resonance (CMR) has been utilized in the management and care of pediatric patients for nearly 40 years. It has evolved to become an invaluable tool in the assessment of the littlest of hearts for diagnosis, pre-interventional management and follow-up care. Although mentioned in a number of consensus and guidelines documents, an up-to-date, large, stand-alone guidance work for the use of CMR in pediatric congenital 36 and acquired 35 heart disease endorsed by numerous Societies involved in the care of these children is lacking. This guidelines document outlines the use of CMR in this patient population for a significant number of heart lesions in this age group and although admittedly, is not an exhaustive treatment, it does deal with an expansive list of many common clinical issues encountered in daily practice.

Society for Cardiovascular Magnetic Resonance/European Society of Cardiovascular Imaging/American Society of Echocardiography/Society for Pediatric Radiology/North American Society for Cardiovascular Imaging Guidelines for the Use of Cardiac Magnetic Resonance in Pediatric Congenital and Acquired Heart Disease: Endorsed by The American Heart Association

Cardiovascular magnetic resonance has been utilized in the management and care of pediatric patients for nearly 40 years. It has evolved to become an invaluable tool in the assessment of the littlest of hearts for diagnosis, pre-interventional management and follow-up care. Although mentioned in a number of consensus and guidelines documents, an up-to-date, large, stand-alone guidance work for the use of cardiovascular magnetic resonance in pediatric congenital 36 and acquired 35 heart disease endorsed by numerous Societies involved in the care of these children is lacking. This guidelines document outlines the use of cardiovascular magnetic resonance in this patient population for a significant number of heart lesions in this age group and although admittedly, is not an exhaustive treatment, it does deal with an expansive list of many common clinical issues encountered in daily practice.

The Interplay between Myocardial Fibrosis, Strain Imaging and Collagen Biomarkers in Adults with Repaired Tetralogy of Fallot

Background: We sought to assess the interplay between right ventricle (RV) fibrosis, biventricular dysfunction based on global longitudinal strain (GLS) analysis, and biomarkers such as Galectin-3 (Gal-3), procollagen type III (PCIII), and NTproBNP. Methods: We studied 35 adult patients with rToF. All patients underwent a cardiac magnetic resonance (CMR) scan including feature tracking for deformation imaging. Blood biomarkers were measured. Results: LGE RV was detected in all patients, mainly at surgical sites. Patients with the highest RV LGE scoring had greater RV dilatation and dysfunction whereas left ventricular (LV) function was preserved. LV GLS correlated with RV total fibrosis score (p = 0.007). A LV GLS value of −15.9% predicted LGE RV score > 8 (AUC 0.754 (p = 0.02)). Neither RV GLS nor biomarker levels were correlated with the extent of RV fibrosis. A cut-off value for NTproBNP of 145.25 pg/mL predicted LGE RV score > 8 points (AUC 0.729, (p = 0.03)). A cut-off value for Gal-3 of 7.42 ng/mL predicted PR Fraction > 20% [AUC 0.704, (p = 0.05)]. Conclusions: A significant extent of RV fibrosis was mainly detected at surgical sites of RV, affecting RV performance. CMR-FT reveals subtle LV dysfunction in rToF patients, due to decreased performance of the fibrotic RV. Impaired LV function and elevated NTproBNP in rToF reflect a dysfunctional fibrotic RV.

Valvular heart disease in congenital heart disease: a narrative review

Patients with congenital heart disease (CHD) are one of the fastest growing populations in cardiology, and valvular pathology is at the center of many congenital lesions. Derangements in valvular embryology lead to several anomalies prone to dysfunction, each with hemodynamic effects that require appropriate surveillance and management. Surgical innovation has provided new treatments that have improved survival in this population, though has also contributed to esotericism in patients who already have unique anatomic and physiologic considerations. Conduit and prosthesis durability are often monitored collaboratively with general and specialized congenital-focused cardiologists. As such, general cardiologists must become familiar with valvular disease with CHD for appropriate care and referral practices. In this review, we summarize the embryology of the semilunar and atrioventricular (AV) valves as a foundation for understanding the origins of valvular CHD and describe the mechanisms that account for heterogeneity in disease. We then highlight the categories of pathology from the simple (e.g., bicuspid aortic valve, isolated pulmonic stenosis) to the more complex (e.g., Ebstein's anomaly, AV valvular disease in single ventricle circulations) with details on natural history, diagnosis, and contemporary therapeutic approaches. Care for CHD patients requires collaborative effort between providers, both CHD-specialized and not, to achieve optimal patient outcomes.

Impact of pulmonary valve replacement on left ventricular rotational mechanics in repaired tetralogy of Fallot

BACKGROUND

In repaired tetralogy of Fallot (rTOF), abnormal left ventricular (LV) rotational mechanics are associated with adverse clinical outcomes. We performed a comprehensive analysis of LV rotational mechanics in rTOF patients using cardiac magnetic resonance (CMR) prior to and following surgical pulmonary valve replacement (PVR).

METHODS

In this single center retrospective study, we identified rTOF patients who (1) had both a CMR ≤ 1 year before PVR and ≤ 5 years after PVR, (2) had no other intervening procedure between CMRs, (3) had a body surface area > 1.0 m2 at CMR, and (4) had images suitable for feature tracking analysis. These subjects were matched to healthy age- and sex-matched control subjects. CMR feature tracking analysis was performed on a ventricular short-axis stack of balanced steady-state free precession images. Measurements included LV basal and apical rotation, twist, torsion, peak systolic rates of rotation and torsion, and timing of events. Associations with LV torsion were assessed.

RESULTS

A total of 60 rTOF patients (23.6 ± 7.9 years, 52% male) and 30 healthy control subjects (20.8 ± 3.1 years, 50% male) were included. Compared with healthy controls, rTOF patients had lower apical and basal rotation, twist, torsion, and systolic rotation rates, and these parameters peaked earlier in systole. The only parameters that were correlated with LV torsion were right ventricular (RV) end-systolic volume (r = - 0.28, p = 0.029) and RV ejection fraction (r = 0.26, p = 0.044). At a median of 1.0 year (IQR 0.5-1.7) following PVR, there was no significant change in LV rotational parameters versus pre-PVR despite reductions in RV volumes, RV mass, pulmonary regurgitation, and RV outflow tract obstruction.

CONCLUSION

In this comprehensive study of CMR-derived LV rotational mechanics in rTOF patients, rotation, twist, and torsion were diminished compared to controls and did not improve at a median of 1 year after PVR despite favorable RV remodeling.

Pulmonary Valve Replacement in Tetralogy of Fallot: An Updated Meta-Analysis

BACKGROUND

The benefits of pulmonary valve replacement (PVR) for pulmonary insufficiency in patients with repaired tetralogy of Fallot are still incompletely understood, and optimal timing remains challenging.

METHODS

We systematically reviewed databases (PubMed/MEDLINE, Embase, Cochrane Central Register of Controlled Trials /Cochrane Controlled Trials Register, ClinicalTrials.gov, Scientific Electronic Library Online, Literatura Latino Americana em Ciências da Saúde, and Google Scholar) and reference lists of relevant articles for studies about PVR in repaired tetralogy of Fallot patients that reported any of the following outcomes: mortality and redo PVR rates, right ventricular (RV) and left ventricular measures, QRS duration, cardiopulmonary exercise test results, or brain natriuretic peptide. In addition to calculating the pooled treatment effects using a random-effects meta-analysis, we evaluated the effect of preoperative measures on PVR outcomes using meta-regressions.

RESULTS

Eighty-four studies involving 7544 patients met the eligibility criteria. Pooled mortality at 30 days, 5 years, and 10 years after PVR was 0.87% (63 of 7253 patients, 80 studies), 2.7% (132 of 4952 patients, 37 studies), and 6.2% (510 of 2765 patients, 15 studies), respectively. Pooled 5- and 10-year redo PVR rates were 3.7% (141 of 3755 patients, 23 studies) and 16.8% (172 of 3035 patients, 16 studies), respectively. The results of the previous meta-analysis could be confirmed. In addition, we demonstrated that after PVR (1) QRS duration, cardiopulmonary exercise test results, and RV and left ventricular measures longitudinal strain do not significantly change; (2) brain natriuretic peptide decreases; and (3) greater indexed RV end-diastolic and end-systolic volumes are associated with lower chances of RV volume normalization after PVR.

CONCLUSIONS

This updated meta-analysis provides evidence about the benefits of PVR.

The impact of pulmonary regurgitation on right ventricular size and function in patients with repaired tetralogy of Fallot and additional haemodynamic abnormalities

Purpose

Right ventricular (RV) outflow tract obstruction (RVOTO) was demonstrated to be protective against RV dilatation in patients with repaired tetralogy of Fallot and chronic pulmonary regurgitation (PR). We hypothesised that the presence of additional haemodynamic abnormalities (more than mild tricuspid regurgitation, residual ventricular septal defect) reduces this protective association. Accordingly, we aimed to assess the impact of PR on RV size and function in this population.

Material and methods

Consecutive patients with additional haemodynamic abnormalities after tetralogy of Fallot (TOF) repair, who had undergone cardiovascular magnetic resonance, were included.

Results

Out of 90 patients studied, 18 individuals (mean age 32.5 ± 10.7 years, 72.2% males) met the inclusion criteria. There were no differences in RV volumes and ejection fraction between patients with and without RVOTO. Neither PR fraction (PRF) nor PR volume (PRV) correlated with RV end-diastolic volume (r = 0.36; p = 0.15 and r = 0.37; p = 0.14, respectively, for PRF and PRV) or RV end-systolic volume (r = 0.2; p = 0.42 and r = 0.19; p = 0.45, respectively, for PRF and PRV). Similarly, no significant correlations were observed between PRF or PRV and RV ejection fraction (r = –0.04; p = 0.87 and r = –0.03; p = 0.9, respectively).

Conclusions

Additional haemodynamic abnormalities are associated with the abolition of the protective effect of RVOTO on RV size. There was no significant relationship between measures of PR and RV volumes in patients after TOF repair with concomitant haemodynamic abnormalities. These abnormalities acted as confounding factors in the assessment of the impact of pulmonary regurgitation on RV size and function.

Changes in Right Ventricular Volume, Volume Load, and Function Measured with Cardiac Computed Tomography over the Entire Time Course of Tetralogy of Fallot

Objective

To characterize the changes in right ventricular (RV) volume, volume load, and function measured with cardiac computed tomography (CT) over the entire time course of tetralogy of Fallot (TOF).

Materials and Methods

In 374 patients with TOF, the ventricular volume, ventricular function, and RV volume load were measured with cardiac CT preoperatively (stage 1), after palliative operation (stage 2), after total surgical repair (stage 3), or after pulmonary valve replacement (PVR) (stage 4). The CT-measured variables were compared among the four stages. After total surgical repair, the postoperative duration (POD) and the CT-measured variables were correlated with each other. In addition, the demographic and CT-measured variables in the early postoperative groups were compared with those in the late postoperative and the preoperative group.

Results

Significantly different CT-based measures were found between stages 1 and 3 (indexed RV end-diastolic volume [EDV], 63.6 ± 15.2 mL/m² vs. 147.0 ± 38.5 mL/m² and indexed stroke volume (SV) difference, 7.7 ± 10.3 mL/m² vs. 32.2 ± 16.4 mL/m²; p < 0.001), and between stages 2 and 3 (indexed RV EDV, 72.4 ± 19.7 mL/m² vs. 147.0 ± 38.5 mL/m² and indexed SV difference, 5.7 ± 13.1 mL/m² vs. 32.2 ± 16.4 mL/m²; p < 0.001). After PVR, the effect of RV volume load (i.e., indexed SV difference) was reduced from 32.2 mL/m² to 1.7 mL/m². Positive (0.2 to 0.8) or negative (−0.2 to −0.4) correlations were found among the CT-based measures except between the RV ejection fraction (EF) and the RV volume load parameters. With increasing POD, an early rapid increase was followed by a slow increase and a plateau in the indexed ventricular volumes and the RV volume load parameters. Compared with the preoperative data, larger ventricular volumes and lower EFs were observed in the early postoperative period.

Conclusion

Cardiac CT can be used to characterize RV volume, volume load, and function over the entire time course of TOF.

Impact of surgical pulmonary valve replacement on ventricular strain and synchrony in patients with repaired tetralogy of Fallot: a cardiovascular magnetic resonance feature tracking study

BACKGROUND

In patients with repaired tetralogy of Fallot (TOF), a better understanding of the impact of surgical pulmonary valve replacement (PVR) on ventricular mechanics may lead to improved indications and outcomes. Therefore, we used cardiovascular magnetic resonance (CMR) feature tracking analysis to quantify ventricular strain and synchrony in repaired TOF patients before and after PVR.

METHODS

Thirty-six repaired TOF patients (median age 22.4 years) prospectively underwent CMR a mean of 4.5 ± 3.8 months before PVR surgery and 7.3 ± 2.1 months after PVR surgery. Feature tracking analysis on cine steady-state free precession images was used to measure right ventricular (RV) and left ventricular (LV) circumferential strain from short-axis views at basal, mid-ventricular, and apical levels; and longitudinal strain from 4-chamber views. Intraventricular synchrony was quantified using the maximum difference in time-to-peak strain, the standard deviation of the time-to-peak, and cross correlation delay (CCD) metrics; interventricular synchrony was assessed using the CCD metric.

RESULTS

Following PVR, RV end-diastolic volume, end-systolic volume, and ejection fraction declined, and LV end-diastolic volume and end-systolic volume both increased with no significant change in the LV ejection fraction. LV global basal and apical circumferential strains, and basal synchrony improved. RV global circumferential and longitudinal strains were unchanged, and there was a varied impact on synchrony across the locations. Interventricular synchrony worsened at the midventricular level but was unchanged at the base and apex, and on 4-chamber views.

CONCLUSIONS

Surgical PVR in repaired TOF patients led to improved LV global strain and no change in RV global strain. LV and RV synchrony parameters improved or were unchanged, and interventricular synchrony worsened at the midventricular level.

Pulmonic Valve Disease: Review of Pathology and Current Treatment Options

PURPOSE OF REVIEW

Our review is intended to provide readers with an overview of disease processes involving the pulmonic valve, highlighting recent outcome studies and guideline-based recommendations; with focus on the two most common interventions for treating pulmonic valve disease, balloon pulmonary valvuloplasty and pulmonic valve replacement.

RECENT FINDINGS

The main long-term sequelae of balloon pulmonary valvuloplasty, the gold standard treatment for pulmonic stenosis, remain pulmonic regurgitation and valvular restenosis. The balloon:annulus ratio is a major contributor to both, with high ratios resulting in greater degrees of regurgitation, and small ratios increasing risk for restenosis. Recent studies suggest that a ratio of approximately 1.2 may provide the most optimal results. Pulmonic valve replacement is currently the procedure of choice for patients with severe pulmonic regurgitation and hemodynamic sequelae or symptoms, yet it remains uncertain how it impacts long-term survival. Transcatheter pulmonic valve replacement is a rapidly evolving field and recent outcome studies suggest short and mid-term results at least equivalent to surgery. The Melody valve® was FDA approved for failing pulmonary surgical conduits in 2010 and for failing bioprosthetic surgical pulmonic valves in 2017 and has been extensively studied, whereas the Sapien XT valve®, offering larger diameters, was approved for failing pulmonary conduits in 2016 and has been less extensively studied. Patients with pulmonic valve disease deserve lifelong surveillance for complications. Transcatheter pulmonic valve replacement is a novel and attractive therapeutic option, but is currently only FDA approved for patients with failing pulmonary conduits or dysfunctional surgical bioprosthetic valves. New advances will undoubtedly increase the utilization of this rapidly expanding technology.

Imaging the adult with transposition of the great arteries

PURPOSE OF REVIEW

Patients with complete and congenitally corrected transposition of the great arteries commonly survive into adulthood and present with a vast array of clinical residua.

RECENT FINDINGS

Echocardiography remains the primary imaging modality in the routine assessment of the adult with transposition of the great arteries. It provides a comprehensive anatomic and hemodynamic evaluation. Limitations to echocardiography include evaluation of the following: the systemic right ventricle, baffle patency following atrial switch procedure, coronary arteries following arterial switch procedure or Nikadoh, and multilevel right ventricular outflow tract obstruction.

SUMMARY

Each form of palliation for transposition of the great arteries results in unique long-term sequelae that affect outcomes. A multimodality approach to imaging is required for a complete evaluation.

Variability of Pulmonary Regurgitation in Proportion to Pulmonary Vascular Resistance in a Porcine Model of Total Resection of the Pulmonary Valve: Implications for Early- and Long-Term Postoperative Management of Right Ventricular Outflow Tract Reconstruction With Resulting Pulmonary Valve Incompetence

INTRODUCTION

Pulmonary regurgitation (PR) is a major concern after right ventricular (RV) outflow tract surgery. We assessed the impact of physiological changes in pulmonary vasculature on hemodynamic severity of PR and RV function and their potential clinical implications for postoperative management using a porcine model with severe PR.

MATERIALS AND METHODS

Eight porcine models of acute PR were established by means of resection of pulmonary valve on cardiopulmonary bypass. After separation from bypass and stabilization, blood flow in the main pulmonary artery was measured by a pulsed Doppler flowmeter, and RV systolic function was assessed on the basis of RV segment shortening (RVSS), which was analyzed by sonomicrometry. In the acute PR model, we verified the impact of pulmonary vascular resistance (Rp) on pulmonary regurgitant fraction (PRF) and RV function. Pulmonary vascular resistance was changed by manipulating the level of PaCo 2 and by inhalation of nitric oxide (NO).

RESULTS

After bypass, the mean PRF was 40% ± 5%, and there was a deterioration of RV function. Under each ventilation condition (high CO2, low CO2, and NO 20 ppm), Rp was 836 ± 207 dyne × s × cm(-5), 499 ± 125 dyne × s × cm(-5), and 340 ± 102 dyne × s × cm(-5), respectively, and PRF was 60% ± 10%, 37% ± 5%, and 24% ± 4%, respectively, under each condition. They also showed a positive correlation in all animals. Cardiac output and RVSS were decreased by hypercapnia, while they were significantly improved after NO inhalation.

CONCLUSIONS

This study indicates that low Rp after right ventricular outflow tract reconstruction (RVOTR) resulting in acute PR is advantageous in reducing the severity of PR and RV volume load. These findings may have clinical implications for early and long-term postoperative management of patients subjected to RVOTR with resulting pulmonary valve incompetence.

The Cardiovascular Effects of Obesity on Ventricular Function and Mass in Patients after Tetralogy of Fallot Repair

OBJECTIVES

To determine the cardiovascular effects of obesity on patients with tetralogy of Fallot (TOF) repair.

STUDY DESIGN

Ventricular performance measures were compared between obese (body mass index [BMI] ≥95%), overweight (85% ≤BMI <95%), and normal weight subjects (BMI <85%) in a retrospective review of patients with TOF who underwent cardiac magnetic resonance from 2005-2010. Significance was P < .05.

RESULTS

Of 260 consecutive patients with TOF, 32 were obese (12.3%), 48 were overweight (18.5%), and 180 were normal weight (69.2%). Biventricular mass was increased in obese compared with normal weight patients with right ventricular mass more affected than left ventricular mass. Obese patients demonstrated decreased biventricular end-diastolic volume (EDV) and stroke volume (SV) when indexed to body surface area (BSA) with an increased heart rate when compared with normal weight patients; cardiac index, ejection fraction, and pulmonary regurgitation fraction were similar. When indexed to ideal BSA, biventricular EDV and SV were similar. EDV and SV for overweight patients were nearly identical to normal weight patients with ventricular mass in between the other 2 groups.

CONCLUSIONS

Approximately 12% of patients after TOF repair referred for cardiac magnetic resonance in a tertiary referral center are obese with increased biventricular mass. Obese patients and normal weight patients have similar cardiac indices, however, when indexed to actual BSA, obese patients demonstrate decreased EDV and SV with increased heart rate and similar cardiac indices. When indexed to ideal BSA, no differences in biventricular volumes were noted.

Resting heart rate influences right ventricular volume in repaired tetralogy of Fallot

The aim of this study is to examine the impact of heart rate (HR) on right ventricular end-diastolic volume indexed to body surface area (RVEDVi) in patients with repaired tetralogy of Fallot (TOF). In this cross-sectional study, an institutional database search identified all patients with repaired TOF who underwent cardiac magnetic resonance (CMR) and had a Holter study within 3 months. The association of HR on Holter, HR at the time of CMR, and other clinical and CMR parameters on RVEDVi was explored with univariate and then multivariable models. In the study group (n = 161, median age 23 years), a lower mean Holter HR was associated with a larger RVEDVi (p = 0.004). In a model that also included pulmonary regurgitation fraction, tricuspid regurgitation grade, RV ejection fraction, age at CMR, and gender, mean Holter HR remained associated with RVEDVi (p < 0.0001); for a decrease of 1 bpm, mean RVEDVi increased by 1.09 ml/m(2). When limiting to those with a Holter within 5 days of CMR (n = 70), the impact of mean Holter HR on RVEDVi was stronger (-1.9 ml/m(2)/bpm). HR at time of CMR had a significant but less pronounced relationship to RVEDVi (-0.58 ml/m(2)/bpm, p = 0.002). In conclusion, in repaired TOF patients, a lower HR was significantly associated with a larger RVEDVi. This relationship was stronger with a shorter time interval between the Holter and CMR, and stronger for the mean HR on Holter than for the HR at CMR. Accounting for HR in the interpretation of RVEDVi may impact decisions regarding pulmonary valve replacement and the interpretation of serial CMR data.

Imaging of the right heart--CT and CMR

Right ventricular (RV) structure and function is of substantial importance in a broad variety of clinical conditions. Cardiac magnetic resonance (CMR) and computed tomography (CT) each provide three-dimensional RV imaging, high-resolution evaluation of RV structure/anatomy, and accurate functional assessment without geometric assumptions. This is of particular significance for the RV, where complex geometry compromises reliance on indices derived from two-dimensional (2D) imaging planes. CMR flow-based imaging can be applied to right-sided heart valves, enabling evaluation of hemodynamic and valvular dysfunction that may contribute to or result from RV dysfunction. Tissue characterization imaging by both CMR and CT provides valuable complementary assessment of the RV. Changes in myocardial tissue composition provide a mechanistic substrate for RV dysfunction and cardiac arrhythmias. This review provides an overview of RV imaging by both CMR and CT, with focus on assessment of RV structure/function, flow, and tissue characterization. Emerging evidence and established guidelines are discussed in the context of imaging contributions to diagnosis, prognostic risk stratification and disease management of clinical conditions that impact the right ventricle.

Relation of aortic stiffness and strain by cardiovascular magnetic resonance imaging to age in repaired tetralogy of fallot

Patients with tetralogy of Fallot (TOF) have abnormal aortic properties. It is not known if this increases the risk for aneurysm formation. We sought to identify clinical and cardiovascular magnetic resonance (CMR) imaging patient characteristics associated with worsened aortic pulse wave velocity (PWV) and aortic strain in patients with repaired TOF. In 124 patients with TOF undergoing CMR (median age 24.6 years, interquartile range 17.8 to 34.2), left and right ventricular volumetric data, aortic PWV, and aortic strain were evaluated. Increased PWV positively correlated with age at repair (r = 0.3, p = 0.001) and cross-sectional ascending aortic area (r = 0.34, p <0.001) and was associated with a history of shunt placement (p = 0.01). Decreased aortic strain also correlated with age at TOF repair (r = -0.5, p <0.001), cross-sectional ascending aortic area (r = -0.43, p <0.001), aortic regurgitation (r = -0.46, p ≤0.001), and history of shunt placement (p <0.001). In a multivariate regression model controlling for history of shunt placement, use of cardiac medication, and aortic regurgitation, age at CMR was significantly associated with PWV (p = 0.005), whereas age at repair trended toward significance (p = 0.06). In conclusion, patients with TOF have abnormal aortic properties correlated with greater age, which may be associated with later repair. Longitudinal data are necessary to assess the risk of aortic aneurysm and dissection as the TOF population grows older. Functional imaging of the aorta by CMR may be useful in predicting risk and assessing vascular health.

Impact of transcatheter pulmonary valve replacement on biventricular strain and synchrony assessed by cardiac magnetic resonance feature tracking

BACKGROUND

Transcatheter pulmonary valve (TPV) replacement is an emerging therapy intended to restore pulmonary valve function in patients with right ventricular outflow tract conduit dysfunction; the impact of this technique on ventricular strain and synchrony is not known.

METHODS AND RESULTS

Cardiac magnetic resonance and ECG data acquired at 1 center as part of the US Melody TPV trial were analyzed. Biventricular strain and mechanical synchrony measurements were made based on short-axis and 4-chamber steady-state free precession images using feature tracking software. Post- versus pre-TPV replacement findings were compared for all patients (n=31) and subgroups with predominant pulmonary regurgitation (n=13) or stenosis (n=18). Most patients had tetralogy of Fallot (18/31). After TPV replacement, left ventricular (LV) circumferential strain increased for the whole cohort (P<0.001) and both subgroups (pulmonary regurgitation P=0.01; pulmonary stenosis P=0.02). LV longitudinal strain increased for the whole cohort (P=0.02) and pulmonary regurgitation subgroup (P=0.05); circumferential right ventricular strain increased for the pulmonary stenosis group only (P=0.05). LV longitudinal synchrony improved significantly in the pulmonary regurgitation group (maximum wall delay P=0.03; cross-correlation delay P=0.01). Electric measures of synchrony did not improve.

CONCLUSIONS

In patients with right ventricular outflow tract conduit dysfunction, TPV replacement is associated with improved global LV strain, as well as improved right ventricular strain and LV synchrony in subgroups. Given the associations between strain and synchrony and clinical outcomes, these findings support potential long-term benefits of TPV replacement.

Rationale and design of an International Multicenter Registry of patients with repaired tetralogy of Fallot to define risk factors for late adverse outcomes: the INDICATOR cohort

Although early survival after tetralogy of Fallot (TOF) repair in the modern era is excellent, studies on late outcomes have shown increasing rates of mortality and morbidity. Despite multiple publications on factors associated with late complications, risk factors for major outcomes (death and sustained ventricular tachycardia [VT]) remain poorly defined. Consequently, the International Multicenter TOF Registry (INDICATOR) was established. This article describes the development, structure, and goals of this registry and characterizes the initial cohort derived from four large congenital heart centers in the United States, Canada, and Europe. A data coordinating center with a core cardiac magnetic resonance (CMR) laboratory and statistical core was established. Subjects with repaired TOF who had CMR imaging performed between 1997 and 2010 and ≥ 1 year follow-up were included. Clinical end points were death and sustained VT. Demographic, electrophysiologic, exercise, and outcome data were collected. A total of 873 subjects fulfilled inclusion criteria (median age at repair 2.9 years and at CMR imaging 22.8 years). Of these, 9 % had QRS duration >180 ms on electrocardiogram (ECG). On CMR imaging, 38 % had severe right-ventricular (RV) dilatation (≥ 160 mL/m(2)), and 6 % had severe RV dysfunction (ejection fraction < 35 %). Of the 551 subjects with exercise testing available, 28 % had severely decreased exercise capacity with <50 % predicted peak oxygen consumption. The INDICATOR cohort allows robust statistical analysis to evaluate major clinical outcomes in patients with repaired TOF. Continued follow-up and further expansion of the registry may provide new insights into innovative therapeutic strategies to improve late outcomes.

Surgical management of chronic pulmonary regurgitation after relief of right ventricular outflow tract obstruction

Relief of right ventricular (RV) outflow tract obstruction in tetralogy of Fallot or similar physiology often results in pulmonary regurgitation (PR). The resultant chronic volume overload can lead to RV dilatation, biventricular dysfunction, heart failure symptoms, arrhythmias and sudden death. Although pulmonary valve replacement (PVR) can lead to improvement in the functional class and a substantial decrease or normalization of RV volumes, the optimal timing of PVR is not well defined. Benefits of PVR have to be weighed against the risks of this procedure including subsequent reoperation. This article reviews the pathophysiology of chronic PR, evidence-based benefits and risks of PVR, options for valve substitute, and optimal timing of PVR in patients with chronic PR after relief of RV outflow tract obstruction.

Timing and technique of pulmonary valve replacement in the patient with tetralogy of Fallot

Residual right ventricular (RV) outflow tract pathology is universal among patients with repaired tetralogy of Fallot, and pulmonary regurgitation (PR) is also commonly present. Although tolerated in early life, by the second decade of life PR is associated with an increased risk of death because of ventricular arrhythmias. Pulmonary valve replacement (PVR) is a safe procedure that will eliminate PR, but timing and indications are evolving. Patients with arrhythmias or prolonged QRS duration are candidates for PVR. Patients with symptomatic exercise intolerance are likely to have improvement in symptoms and quality of life and should be offered PVR. Cardiac magnetic resonance has become an essential component of the management of the patient with tetralogy of Fallot with PR, and has identified the potential for and limitations of RV remodeling following PVR. Among patients with severe RV enlargement, particularly those with diminished RV or left ventricular function, there is an increased risk of adverse events and even asymptomatic patients with severe PR should be considered for PVR. Valve replacement is accomplished with homografts or heterografts, either stented bioprosthetic valves or valved conduits. In a retrospective analysis of the Children's Hospital of Wisconsin experience with PVR, there was no difference in survival or freedom from reintervention between heterografts and homografts.

The role of cardiovascular magnetic resonance in adults with congenital heart disease

The comprehensive coverage and versatility of cardiovascular magnetic resonance (CMR), providing functional as well as anatomical information, make it an important facility in a center specializing in the care of adults with congenital heart disease. Imaging specialists using CMR to investigate acquired heart disease should also be able to recognize and evaluate previously unsuspected congenital malformations. Conditions that may present or be picked up during imaging in adulthood include atrial septal defect, anomalously connected pulmonary veins, double-chambered right ventricle, congenitally corrected transposition of the great arteries, aortic coarctation, and patent arterial duct. To realize its full potential and to avoid pitfalls, CMR of adults with congenital heart disease requires specific training and experience. Appropriate pathophysiological understanding is needed to evaluate cardiovascular function after surgery for tetralogy of Fallot, after transposition of the great arteries, and after Fontan operations. For these and other more complex cases, CMR should ideally be undertaken by specialists committed to long-term collaboration with the clinicians and surgeons managing the patients in a tertiary referral center.

Imaging congenital heart disease in adults

Transthoracic echocardiography is the first-line modality for cardiovascular imaging in adults with congenital heart disease (ACHD). The windows of access that are possible with transthoracic echocardiography are, however, rarely adequate for all regions of interest. The choice of further imaging depends on the clinical questions that remain to be addressed. The strengths of MRI include comprehensive access and coverage, providing imaging of all parts of the right ventricle, the pulmonary arteries, pulmonary veins and aorta. Cine images and velocity maps are acquired in specifically aligned planes, with stacks of cines or dynamic contrast angiography providing more comprehensive coverage. Tissues can be characterised if necessary, and MRI provides relatively accurate measurements of biventricular function and volume flow. These parameters are important in the assessment and follow-up of adults after repairs for tetralogy of Fallot or transposition of the great arteries and after Fontan operations. The superior spatial resolution and rapid acquisition of CT are invaluable in selected situations, including the visualisation of anomalous coronary or aortopulmonary collateral arteries, the assessment of luminal patency after stenting and imaging in patients with pacemakers. Ionising radiation is, however, a concern in younger patients who may need repeated investigation. Adults with relatively complex conditions should ideally be imaged in a specialist ACHD centre, where dedicated echocardiographic and cardiovascular MRI services are a necessary facility. General radiologists should be aware of the nature and pathophysiology of congenital heart disease, and should be alert for previously undiagnosed cases presenting in adulthood, including cases of atrial septal defect, aortic coarctation, patent ductus arteriosus, double-chambered right ventricle and congenitally corrected transposition.

A statistical model for quantification and prediction of cardiac remodelling: application to tetralogy of Fallot

Cardiac remodelling plays a crucial role in heart diseases. Analyzing how the heart grows and remodels over time can provide precious insights into pathological mechanisms, eventually resulting in quantitative metrics for disease evaluation and therapy planning. This study aims to quantify the regional impacts of valve regurgitation and heart growth upon the end-diastolic right ventricle (RV) in patients with tetralogy of Fallot, a severe congenital heart defect. The ultimate goal is to determine, among clinical variables, predictors for the RV shape from which a statistical model that predicts RV remodelling is built. Our approach relies on a forward model based on currents and a diffeomorphic surface registration algorithm to estimate an unbiased template. Local effects of RV regurgitation upon the RV shape were assessed with Principal Component Analysis (PCA) and cross-sectional multivariate design. A generative 3-D model of RV growth was then estimated using partial least squares (PLS) and canonical correlation analysis (CCA). Applied on a retrospective population of 49 patients, cross-effects between growth and pathology could be identified. Qualitatively, the statistical findings were found realistic by cardiologists. 10-fold cross-validation demonstrated a promising generalization and stability of the growth model. Compared to PCA regression, PLS was more compact, more precise and provided better predictions.

Relation of left ventricular dyssynchrony measured by cardiac magnetic resonance tissue tracking in repaired tetralogy of fallot to ventricular tachycardia and death

The impact of left ventricular (LV) dyssynchrony on clinical outcomes in patients with tetralogy of Fallot (TOF) is unknown. The aim of this study was to test the hypothesis that LV dyssynchrony assessed by cardiac magnetic resonance (CMR)-derived tissue tracking in patients with repaired TOF is associated with ventricular tachycardia (VT) and death. Included patients had repaired TOF and CMR data from 2000 and 2008. Patients (n = 13) had histories of death or sustained VT. Control subjects (n = 26), with no death or VT, were matched by age at CMR and type of last surgical procedure. Demographic, clinical, and electrocardiographic data were recorded. CMR short-axis cine data were analyzed by tracking the motion of the endocardial border using commercial software. LV dyssynchrony was quantified as the maximum difference in time to peak radial displacement, circumferential strain, and radial strain among the 6 ventricular segments and the standard deviation of the times to peak value. There were no differences between groups in clinical, electrocardiographic, or demographic characteristics. Among CMR parameters, right ventricular volumes were higher and ejection fractions lower in the patient group. Indexes of LV dyssynchrony were higher in the patient group (e.g., maximum time difference of circumferential strain 94 vs 46 ms, p <0.001; standard deviation of circumferential strain 37.8 vs 20.3 ms, p <0.01). In a multivariate model including LV synchrony variables, the best outcome discriminator was maximum time difference to peak circumferential strain (p <0.01). In conclusion, tissue tracking applied to CMR images identifies indexes of LV synchrony associated with death and VT in patients with repaired TOF.

Limitations of standard echocardiographic methods for quantification of right ventricular size and function in children and young adults

OBJECTIVES

The aim of this study was to evaluate correlation of 2-dimensional (2D) echocardiographic assessment of right ventricular (RV) and left ventricular (LV) size and function with magnetic resonance imaging (MRI) in children and young adults.

METHODS

Patients with repaired tetralogy of Fallot (n = 23) and those who had normal RV volumes (n = 13) and a normal ejection fraction (EF) by MRI constituted the study groups. Echocardiographic indices including the end-diastolic area (EDa), end-systolic area (ESa), fractional area change (FAC), tricuspid annular motion (TAM), RV basal diameter, and RV basal shortening fraction were compared with MRI ventricular volumes and the EF. Two echocardiographers qualitatively graded RV size and function.

RESULTS

In both groups, neither the RV EDa nor the ESa correlated with MRI RV volumes. Only TAM correlated with the RV EF. Qualitative assessment of the RV showed poor interobserver agreement. The LV area and FAC correlated well with MRI data.

CONCLUSIONS

In contrast to the LV, 2D echocardiographic indices of RV size and function, with the exception of TAM, do not correlate with MRI data.

Repaired tetralogy of Fallot: the roles of cardiovascular magnetic resonance in evaluating pathophysiology and for pulmonary valve replacement decision support

Surgical management of tetralogy of Fallot (TOF) results in anatomic and functional abnormalities in the majority of patients. Although right ventricular volume load due to severe pulmonary regurgitation can be tolerated for many years, there is now evidence that the compensatory mechanisms of the right ventricular myocardium ultimately fail and that if the volume load is not eliminated or reduced by pulmonary valve replacement the dysfunction might be irreversible. Cardiovascular magnetic resonance (CMR) has evolved during the last 2 decades as the reference standard imaging modality to assess the anatomic and functional sequelae in patients with repaired TOF. This article reviews the pathophysiology of chronic right ventricular volume load after TOF repair and the risks and benefits of pulmonary valve replacement. The CMR techniques used to comprehensively evaluate the patient with repaired TOF are reviewed and the role of CMR in supporting clinical decisions regarding pulmonary valve replacement is discussed.

Randomized trial of pulmonary valve replacement with and without right ventricular remodeling surgery

BACKGROUND

Although pulmonary valve replacement (PVR) is effective in reducing right ventricular (RV) volume overload in patients with chronic pulmonary regurgitation, persistent RV dysfunction and subsequent adverse clinical outcomes have been reported. This trial was conducted to investigate whether the addition of surgical RV remodeling with exclusion of scar tissue to PVR would result in improved RV function and laboratory and clinical parameters, as compared with PVR alone.

METHODS AND RESULTS

Between February 2004 and October 2008, 64 patients who underwent RV outflow tract procedures in early childhood had more than or equal to moderate pulmonary regurgitation, and fulfilled defined criteria for PVR were randomly assigned to undergo either PVR alone (n=34) or PVR with surgical RV remodeling (n=30). No significant difference was observed in the primary outcome (change in RV ejection fraction, -2±7% in the PVR alone group and -1±7% in the PVR with RV remodeling group; P=0.38) or in any of the secondary outcomes at 6-month postoperative follow-up. Multivariable analysis of the entire cohort identified preoperative RV end-systolic volume index <90 mL/m(2) and QRS duration <140 ms to be associated with optimal postoperative outcome (normal RV size and function), and RV ejection fraction <45% and QRS duration ≥160 ms to be associated with suboptimal postoperative outcome (RV dilatation and dysfunction).

CONCLUSIONS

The addition of surgical remodeling of the RV to PVR in patients with chronic pulmonary regurgitation did not result in a measurable early benefit. Referral to PVR based on QRS duration, RV end-systolic volume, or RV ejection fraction may be beneficial. Clinical Trial Registration-URL: http://www.clinicaltrials.gov. Unique identifier: NCT00112320.

An echocardiographic model predicting severity of aortic regurgitation in congenital heart disease

Background- Multiple echocardiographic parameters have been identified to predict the severity of aortic regurgitation (AR) with variable reliability. This study was performed to identify which echocardiographic parameters best predict the severity of AR in a cohort of patients with congenital heart disease, using cardiovascular MRI quantification as a reference standard. Methods and Results- The study involved 2 phases. In phase 1, predictive models were developed on the basis of multivariable analysis of various morphometric and Doppler variables obtained from 174 echocardiograms that best predicted the severity of AR as defined by paired cardiovascular MRI examinations. A nonlinear estimate of regurgitation fraction, using the variables parasternal vena contracta-derived area divided by body surface area and abdominal aorta Doppler retrograde velocity-time integral divided by antegrade velocity-time integral, was identified through multivariable analysis as the best predictive model for AR fraction. In phase 2, the predictive models were prospectively tested on 43 echocardiographic examinations for which a paired cardiovascular MRI was performed. The agreement between the observed and predicted AR fraction was assessed using Bland-Altman analysis. For the 30 studies of the validation data set that had adequate quality images of both the parasternal vena contracta width and the abdominal aorta flow profile, the predicted AR values had a mean bias±SD of 0.4±7.3% (P=0.80). Conclusions- A model using the 2 variables parasternal vena contracta-derived area divided by body surface area and abdominal aorta Doppler retrograde velocity-time integral divided by antegrade velocity-time integral can predict AR severity in patients with a wide variety of congenital heart disease.

Recommendations for cardiovascular magnetic resonance in adults with congenital heart disease from the respective working groups of the European Society of Cardiology

This paper aims to provide information and explanations regarding the clinically relevant options, strengths, and limitations of cardiovascular magnetic resonance (CMR) in relation to adults with congenital heart disease (CHD). Cardiovascular magnetic resonance can provide assessments of anatomical connections, biventricular function, myocardial viability, measurements of flow, angiography, and more, without ionizing radiation. It should be regarded as a necessary facility in a centre specializing in the care of adults with CHD. Also, those using CMR to investigate acquired heart disease should be able to recognize and evaluate previously unsuspected CHD such as septal defects, anomalously connected pulmonary veins, or double-chambered right ventricle. To realize its full potential and to avoid pitfalls, however, CMR of CHD requires training and experience. Appropriate pathophysiological understanding is needed to evaluate cardiovascular function after surgery for tetralogy of Fallot, transposition of the great arteries, and after Fontan operations. For these and other complex CHD, CMR should be undertaken by specialists committed to long-term collaboration with the clinicians and surgeons managing the patients. We provide a table of CMR acquisition protocols in relation to CHD categories as a guide towards appropriate use of this uniquely versatile imaging modality.

Long-term pulmonary regurgitation following balloon valvuloplasty for pulmonary stenosis risk factors and relationship to exercise capacity and ventricular volume and function

OBJECTIVES

This study sought to examine the prevalence and predictors of pulmonary regurgitation (PR) following balloon dilation (BD) for pulmonary stenosis (PS) and to investigate its impact on ventricular volume and function, and exercise tolerance.

BACKGROUND

Balloon pulmonary valvuloplasty relieves PS but can cause late PR. The sequelae of isolated PR are not well understood.

METHODS

Patients were at least 7 years of age and 5 years removed from BD, and had no other form of congenital heart disease or significant residual PS. Cardiac magnetic resonance imaging and exercise testing were performed prospectively to quantify PR fraction, ventricular volumes and function, and exercise capacity.

RESULTS

Forty-one patients underwent testing a median of 13.1 years after BD. The median PR fraction was 10%; 14 patients (34%) had PR fraction >15%; 7 (17%) had PR >30%. PR fraction was associated with age at dilation (ln-transformed, R = -0.47, p = 0.002) and balloon:annulus ratio (R = 0.57, p < 0.001). The mean right ventricular (RV) end-diastolic volume z-score was 1.8 +/- 1.9; RV dilation (z-score > or =2) was present in 14/35 patients (40%). PR fraction correlated closely with indexed RV end-diastolic volume (R = 0.79, p < 0.001) and modestly with RV ejection fraction (R = 0.50, p < 0.001). Overall, peak oxygen consumption (Vo(2)) (% predicted) was below average (92 +/- 17%, p = 0.006). Patients with PR fraction >15% had significantly lower peak Vo(2) than those with less PR (85 +/- 17% vs. 96 +/- 16%, p = 0.03).

CONCLUSIONS

Mild PR and RV dilation are common in the long term following BD. A PR fraction >15% is associated with lower peak Vo(2), suggesting that isolated PR and consequent RV dilation are related to impaired exercise cardiopulmonary function.

Reproducibility of MRI measurements of right ventricular size and function in patients with normal and dilated ventricles

PURPOSE

To determine the inter- and intraobserver reproducibility of cardiac magnetic resonance (CMR)-derived measurements of right ventricular (RV) mass, volume, and function in patients with normal and dilated ventricles.

MATERIALS AND METHODS

CMR studies of 60 patients in three groups were studied: a normal RV group (N = 20) and two groups with RV dilation-atrial septal defect (ASD) (N = 20) and repaired tetralogy of Fallot (TOF) (N = 20). Two independent observers analyzed each study on two separate occasions. Inter- and intraobserver reproducibility of biventricular mass, volume, ejection fraction (EF), and stroke volume (SV) measurements were calculated.

RESULTS

High intraclass correlation coefficients (ICC) were found for interobserver (ICC = 0.94-0.99) and intraobserver (ICC = 0.96-0.99) comparisons of RV and left ventricular (LV) mass, volume, and SV measurements. RV and LV EF measurements were less reproducible (ICC = 0.79-0.87). RV mass measurements were significantly less correlated than the respective LV measurements. Small but statistically significant differences in correlation were noted in RV measurements across groups.

CONCLUSION

Except for RV mass, inter- and intraobserver reproducibility of RV size and function measurements is high and generally comparable to that in the LV in patients with both normal and dilated RV.