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Background: The prevalence and determinants of tricuspid regurgitation (TR) in patients with repaired Tetralogy of Fallot (rTOF) remain incompletely understood., Objectives: To explore the prevalence of and factors associated with TR in patients with rTOF, specifically, the relationship of right ventricular (RV) dilatation with TR severity., Methods: Patients (≥17 yrs) with rTOF referred to our service (2000-2019) were identified. Those with severe pulmonary stenosis, significant shunt, or previous tricuspid valve surgery were excluded. Using standard cardiac MRI protocols, RV, right atrial (RA) and tricuspid valve (TV) parameters were measured and compared., Results: 68 consecutively eligible patients with rTOF were included in the study (27 ± 9 yrs., 35% female). Despite substantial RV volume overload (mean RVEDVi 153 mL/m 2 ), the majority of the cohort (78%) had no or only mild TR. RA volumes, tenting height/area and annular diameter were normal (4.9 ± 2.0 mm, 1.1 ± 1.0 cm 2 and 32.4 ± 6.2 mm, respectively). There was no significant correlation of TR fraction with RVEDVi (r = 0.13; p = 0.30), RVEF (r = 0.09; p = 0.44) or tricuspid annular diameter (r = 0.07; p = 0.62). Only RAVi showed a weak but significant correlation with TR fraction (0.29; p = 0.03). In a pooled cohort analysis, including both rTOF patients and adults with a dilated RV from pre-tricuspid shunt lesions, only rTOF was independently associated with higher TR fraction (p = 0.017)., Conclusion: Despite substantial RV dilatation in a cohort with rTOF, there was surprisingly little TR. We found poor correlation between RVEDVi, RA volumes, tricuspid annular dilatation and the presence of significant TR. These findings question commonly held notions regarding the pathophysiology of functional TR in these patients., (Copyright © 2022 Elsevier B.V. All rights reserved.)

Aims: The optimal timing for pulmonary valve replacement in asymptomatic patients with repaired Tetralogy of Fallot (rTOF) and pulmonary regurgitation remains uncertain but is often guided by increases in right ventricular (RV) end-diastolic volume. As cardiopulmonary exercise testing (CPET) performance is a strong prognostic indicator, we assessed which cardiovascular magnetic resonance (CMR) parameters correlate with reductions in exercise capacity to potentially improve identification of high-risk patients., Methods and Results: In all, 163 patients with rTOF (mean age 24.5 ± 10.2 years) who had previously undergone CMR and standardized CPET protocols were included. The indexed right and left ventricular end-diastolic volumes (RVEDVi, LVEDVi), right and left ventricular ejection fractions (RVEF, LVEF), indexed RV stroke volume (RVSVi), and pulmonary regurgitant fraction (PRF) were quantified by CMR and correlated with CPET-determined peak oxygen consumption (VO2) or peak work. On univariable analysis, there was no significant correlation between RVEDVi and PRF with peak VO2 or peak work (% Jones-predicted). In contrast, RVEF and RVSVi had significant correlations with both peak VO2 and peak work that remained significant on multivariable analysis. For a previously established prognostic peak VO2 threshold of <27 mL/kg/min, receiver-operating characteristic curve analysis demonstrated a Harrell's c of 0.70 for RVEF (95% confidence interval 0.61-0.79) with a sensitivity of 88% for RVEF <40%., Conclusion: In rTOF, CMR indices of RV systolic function are better predictors of CPET performance than RV size. An RVEF <40% may be useful to identify prognostically significant reductions in exercise capacity in patients with varying degrees of RV dilatation., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Aims: Pulmonary regurgitation (PR) and right ventricular (RV) dilatation are common in repaired tetralogy of Fallot (rTOF). Left ventricular (LV) dysfunction is an important risk factor in rTOF. The effect of PR/RV dilatation on LV performance and RV-LV interactions in rTOF are incompletely understood. We examined LV responses and exercise capacity in rTOF, both before and after pulmonary valve replacement (PVR)., Methods and Results: Cardiac magnetic resonance imaging scans in 126 rTOF patients (age 17.3 ± 7.6 years) were analysed, comparing subjects with indexed RV end-diastolic volume (RVEDVi) <170 mL/m2 (mild/moderate dilatation, n = 95) and RVEDVi ≥170 mL/m2 (severe dilatation, n = 31). Indexed PR volume (PRVi), RV end-systolic (RVESVi), RV end-diastolic (RVEDVi), RV stroke volume (RVSVi), net pulmonary forward flow (NPFFi), LV end-diastolic (LVEDVi), LV end-systolic (LVESVi), LV stroke volume (LVSVi), RV and LV ejection fraction (EF), and diastolic septal curvature were obtained. Peak aerobic capacity (VO2 max) was measured. In a subset (n = 30), measures were obtained pre-and-post surgical PVR. Compared to those with mild/moderate RV dilatation, patients with severe RV dilation had greater PRVi (38 ± 12 vs. 24 ± 9 mL/m2, P < 0.0001), NPFFi (53 ± 9 vs. 44 ± 11 mL/m2, P < 0.0001), LVEDVi (87 ± 14 vs. 73 ± 13 mL/m2, P < 0.0001), LVESVi (39 ± 12 vs. 30 ± 8 mL/m2, P < 0.0001), and LVSVi (48 ± 7 vs. 43  ±  8 mL/m2, P = 0.002) but lower RV ejection fraction (46 ± 8 vs. 53 ± 7%, P < 0.0001). Septal curvature and VO2 max were similar in both groups. After PVR, there was no change in LVEDVi, LVSVi, septal curvature, or VO2 max., Conclusions: Chronic PR with severe RV dilatation is associated with increased NPFFi, LVEDVi, and LVSVi. This may potentially explain preserved exercise capacity in rTOF with severe PR and RV dilatation., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author(s) 2019. For permissions, please email: journals.permissions@oup.com.)

Background: Quantification of right ventricular (RV) volumes is challenging owing to variable reproducibility and is especially so in congenital heart disease. Cardiac magnetic resonance (CMR) has the ability to more comprehensively survey the entire right ventricle and is currently considered the gold standard., Aims: We aimed to determine the inter-observer reproducibility of CMR-derived RV volumes generated by two independent and experienced (SCMR Level III) observers in Tetralogy of Fallot (ToF) patients with varying degrees of RV dilatation., Methods: We performed a retrospective analysis of 120 consecutive patients with repaired ToF who underwent CMR. Two blinded observers calculated RV volumes in each oblique short axis slice independently. Bland-Altman analysis and inter-observer correlation coefficients (ICC) were assessed., Results: The coefficients of variation for RV parameters were: 2.9%, 8% and 3.4% for right ventricular end diastolic volume (RVEDV), right ventricular end systolic volume (RVESV) and right ventricular ejection fraction (RVEF) respectively. For RVEDV the interobserver correlation was 0.992 demonstrating excellent volumetric correlation between observers. The mean difference between the observers for right ventricular end diastolic volume index (RVEDVi) was 2.5ml/m 2 (95% limits of agreement -7.3 to 12.2ml/m 2 ). For patients with mild-moderate RV dilatation (RVEDVi <150ml/m 2 ) the mean difference of RVEDVi was 1.8ml/m 2 (95% limits of agreement -5.7 to 9.3ml/m 2 ). For patients with severe RV dilatation (RVEDVi≥150ml/m 2 ) the mean difference was -3.4ml/m 2 (95% limits of agreement -8.6 to 15.4ml/m 2 )., Conclusions: In patients with repaired ToF and variable degrees of RV dilatation, CMR assessment of RV volumes and function has high inter-observer reproducibility. This allows for optimal timing of pulmonary valve replacement, based on progression of RV dilatation over time., (Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

The relationship between exercise capacity and right ventricular (RV) structure and function in adult repaired tetralogy of Fallot (TOF) is poorly understood. We therefore aimed to examine the relationships between cardiac MRI and cardiopulmonary exercise test variables in adult repaired TOF patients. In particular, we sought to determine the role of RV mass in determining exercise capacity. Eighty-two adult repaired TOF patients (age at evaluation 26 ± 10 years; mean age at repair 2.5 ± 2.8 years; 23.3 ± 7.9 years since repair; 53 males) (including nine patients with tetralogy-type pulmonary atresia with ventricular septal defect) were prospectively recruited to undergo cardiac MRI and cardiopulmonary exercise testing. As expected, these repaired TOF patients had RV dilatation (indexed RV end-diastolic volume: 153 ± 43.9 mL/m(2)), moderate-severe pulmonary regurgitation (pulmonary regurgitant fraction: 33 ± 14 %) and preserved left (LV ejection fraction: 59 ± 8 %) and RV systolic function (RV ejection fraction: 51 ± 7 %). Exercise capacity was near-normal (peak work: 88 ± 17 % predicted; peak oxygen consumption: 84 ± 17 % predicted). Peak work exhibited a significant positive correlation with RV mass in univariate analysis (r = 0.45, p < 0.001) and (independent of other cardiac MRI variables) in multivariate analyses. For each 10 g higher RV mass, peak work was 8 W higher. Peak work exhibits a significant positive correlation with RV mass, independent of other cardiac MRI variables. RV mass measured on cardiac MRI may provide a novel marker of clinical progress in adult patients with repaired TOF.

Background: The mechanisms whereby cardiac output is augmented with exercise in adult repaired tetralogy of Fallot (TOF) are poorly characterised., Methods: 16 repaired TOF patients (25 ± 7 years of age) and 8 age and sex matched controls (25 ± 4 years of age) underwent cardiopulmonary exercise testing and then real-time cardiac MRI (1.5 T) at rest and whilst exercising within the scanner, aiming for 30% heart rate reserve (Level 1) and 60% heart rate reserve (Level 2), using a custom-built MRI compatible foot pedal device., Results: At rest, TOF patients had severely dilated RVs (indexed RV end-diastolic volume: 149 ± 37 mL/m(2)), moderate-severe PR (regurgitant fraction 35 ± 12%), normal RV fractional area change (FAC) (52 ± 7%) and very mildly impaired exercise capacity (83 ± 15% of predicted maximal work rate). Heart rate and RV FAC increased significantly in TOF patients (75 ± 10 vs 123 ± 17 beats per minute, p<0.001; 44 ± 7 vs 51 ± 10%, p=0.025), and similarly in control subjects (70 ± 11 vs 127 ± 12 beats per minute, p<0.001; 49 ± 7 vs 61 ± 9%, p=0.003), when rest was compared to Level 2. PR fraction decreased significantly but only modestly, from rest to Level 2 in TOF patients (37 ± 15 to 31 ± 15%, p=0.002). Pulmonary artery net forward flow was maintained and did not significantly increase from rest to Level 2 in TOF patients (70 ± 19 vs 69 ± 12 mL/beat, p=0.854) or controls (93 ± 9 vs 95 ± 21 mL/beat, p=0.648)., Conclusions: During exercise in repaired TOF subjects with dilated RV and free PR, increased total RV output per minute was facilitated by an increase in heart rate, an increase in RV FAC and a decrease in PR fraction., (Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.)

Background: Pulmonary valve replacement (PVR) is commonly performed late after Tetralogy of Fallot (TOF) repair. We examined the effects of PVR on cardiac structure, function and exercise capacity in adults with repaired TOF., Methods: Eighteen adult patients with repaired TOF and severe pulmonary regurgitation (PR) with right ventricular (RV) dilatation requiring PVR for clinical reasons (age; 25±8 years) were recruited to undergo cardiac MRI (1.5T) and cardiopulmonary exercise testing before and 14±3 months after PVR., Results: Reduced indexed RV end-diastolic volume (RVEDVi; 186±32mL/m(2) pre-op vs 114±20mL/m(2) post-op, p<0.001) was observed after PVR. "Normalisation" of RVEDVi (≤108mL/m(2)) was achieved in only seven of 18 patients. Pre-PVR RVEDVi correlated with post-operative change in RVEDVi (change=-72.1±20.4mL/m(2), r=-0.815, p<0.001). Exercise capacity remained high-normal post-PVR (% predicted maximal workload: 93±16% vs 91±12%, p=0.5). Regional RV volumes were assessed; RV outflow tract (RVOT) volumes were compared to the RV muscular corpus. Large pre-PVR RVOT volumes correlated negatively with post-surgical RV ejection fraction, peak VO2 and delta VO2 at anaerobic threshold (p<0.05 for all)., Conclusions: Normalisation of RV volume is unlikely to be achieved above a pre-PVR RVEDVi of 165mL/m(2) or more. In particular, an enlarged RVOT prior to PVR predicts suboptimal structural and functional outcomes., (Crown Copyright © 2013. Published by Elsevier B.V. All rights reserved.)

Objectives: To assess if exercise capacity and resting stroke volume are different in tetralogy of Fallot (TOF) repair survivors with indexed RV (right ventricle) end-diastolic volume (RVEDVi) more versus less than 150 ml/m(2), a currently suggested threshold for pulmonary valve replacement (PVR)., Design: Cross-sectional study., Setting: Single-centre adult congenital heart disease unit., Patients: 55 consecutively eligible patients with repaired TOF (age at repair 2.3±1.9 years; age at evaluation 26.2±8.8 years; NYHA Class I or II)., Interventions: Cardiovascular MRI (1.5T) and cardiopulmonary exercise test., Main Outcome Measures: Biventricular volumes and function; exercise capacity., Results: 20 patients had RVEDVi below, and 35 had RVEDVi above 150 ml/m(2), at time of referral. In the >150 ml/m(2) group, fractional pulmonary regurgitation was higher (41±8 vs 31±8%, p<0.001). Although RV ejection fraction (EF) was lower (47±7 vs 54±6%, p=0.007), indexed RV stroke volume was higher (87±14 vs 64±10 ml/m(2), p<0.001) in the >150 ml/m(2) group. There were no significant differences in LVEF, indexed LV stroke volume or exercise capacity (% predicted peak work: 90±17 vs 89±11% and; % predicted VO(2) peak: 84±17 vs 87±12%)., Conclusions: Exercise capacity and stroke volume are maintained with RVEDVi above compared with below a commonly used cut-off for PVR surgery. Optimal timing for PVR, thus, remains unclear.

Objective: Chronic pulmonary regurgitation (PR) has deleterious effects on right ventricular (RV) function in repaired tetralogy of Fallot (ToF). However, there are little data regarding right ventricular outflow tract (RVOT) contractile dysfunction in response to chronic PR and on both RV and LV volumes and function., Methods: We retrospectively identified consecutive patients with PR who were referred for magnetic resonance imaging quantification of "free PR" detected on echocardiography between 2003 and 2008. Patients had ToF and a transannular patch procedure (n = 30, 25.1 ± 1.2 years) or PR resulting from valvar pulmonary stenosis treated with surgical or percutaneous valvotomy (n = 30, 26.6 ± 1.8 years)., Results: The ToF and the PS groups were well matched for age at scan, age at repair surgery in ToF or initial valvotomy in PS, duration of exposure to PR, body surface area, heart rate, PR fraction, net forward pulmonary artery flow, and main and branch pulmonary artery dimensions. Severe PR fractions were identified in both groups (ToF: 40% ± 1% vs PS: 37% ± 2%, P = .2). Indexed RV and LV end-diastolic volumes were similar for both ToF and PS groups (RV end-diastolic volume index: 137 ± 6 mL/m(2) vs 128 ± 5 mL/m(2), P = .2, and LV end-diastolic volume index: 72 ± 2 mL/m(2) vs 67 ± 2 mL/m(2), P = .1, respectively). RV mass was also similar between groups (95 ± 5 g vs 81 ± 6 g, respectively, P = .08). However, indexed RV and LV end-systolic volumes were consistently higher in ToF when compared with PS (RV end-systolic volume index: 70 ± 5 mL/m(2) vs 54 ± 3 mL/m(2), P < .01, and LV end-systolic volume index: 29 ± 1 mL/m(2) vs 22 ± 1 mL/m(2), P < .01, respectively). These changes were reflected in lower biventricular systolic function in patients with ToF when compared with PS (RV ejection fraction: 52% ± 1.5% vs 59% ± 1%, P < .001, and LV ejection fraction: 61% ± 1% vs 67 ± 1%, P < .001, respectively). Although RV transannular plane systolic excursion was not significantly different between the groups (P = .86), the RV outflow tract was considered contractile in only 50% of patients with ToF compared with 93% of patients with PS (P = .0004). RV volumes and function were similar when only patients with contractile RV outflow tracts were compared., Conclusions: RV outflow tract patch dysfunction in repaired ToF is responsible for higher end-systolic volumes and thus lower global measures of ventricular systolic function. These findings were not evident in cases of PS treated with valvotomy with comparable amount of PR. These observations highlight the importance of the initial repair surgery in ToF for late outcomes., (Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.)