Pulmonary Regurgitation Volume Research Articles

Impact of Pulmonary Arterial Elastance on Right Ventricular Mechanics and Exercise Capacity in Repaired Tetralogy of Fallot.

Pathophysiological changes of right ventricle (RV) after repair of tetralogy of Fallot (TOF) are coupled with a highly compliant low-pressure pulmonary artery (PA) system. This study aimed to determine whether pulmonary vascular function was associated with RV parameters and exercise capacity, and its impact on RV remodeling after pulmonary valve replacement. In a total of 48 patients over 18 years of age with repaired TOF, pulmonary arterial elastance (Ea), RV volume data, and RV-PA coupling ratio were calculated and analyzed in relation to exercise capacity. Patients with a low Ea showed a more severe pulmonary regurgitation volume index, greater RV end-diastolic volume index, and greater effective RV stroke volume (p=0.039, p=0.013, and p=0.011, respectively). Patients with a high Ea had lower exercise capacity than those with a low Ea (peak oxygen consumption [peak VO2] rate: 25.8±7.7 vs. 34.3±5.5 mL/kg/min, respectively, p=0.003), while peak VO2 was inversely correlated with Ea and mean PA pressure (p=0.004 and p=0.004, respectively). In the univariate analysis, a higher preoperative RV end-diastolic volume index and RV end-systolic volume index, left ventricular end-systolic volume index, and higher RV-PA coupling ratio were risk factors for suboptimal outcomes. Preoperative RV volume and RV-PA coupling ratio reflecting the adaptive PA system response are important factors in optimal postoperative results. We found that PA vascular dysfunction, presenting as elevated Ea in TOF, may contribute to exercise intolerance. However, Ea was inversely correlated with pulmonary regurgitation (PR) severity, which may prevent PR, RV dilatation, and left ventricular dilatation in the absence of significant pulmonary stenosis.

Effect of percutaneous pulmonary valve replacement on ventricular electrophysiological remodeling in a porcine model of repaired tetralogy of Fallot

Tetralogy of Fallot is the most common cyanotic congenital heart disease. Late after corrective surgery, patients are at risk of developing right ventricular (RV) failure due to pulmonary valve regurgitation and arrhythmias related to surgical scars and ventricular electrophysiological remodeling. Pulmonary valve replacement has been identified as an interesting strategy to reduce RV dilatation but its impact on the arrhythmic risk remains uncertain. We sought to determine whether percutaneous pulmonary valve implantation (PPVI) at an early pathological stage leads to benefical effects on right and left ventricular electrophysiological remodeling in a porcine model of repaired tetralogy of Fallot (rTOF). Piglets (<10 kg) underwent pulmonary artery banding, pulmonary valve disruption to induce RV hypertrophy and dilatation and a PTFE patch was sewn across the pulmonary annulus. Two-months later, PPVI was performed in a sub-group of rTOF pigs. At 3 months post-surgery, cardiac function was assessed by MRI in rTOF, rTOF-PPVI and Sham-operated pigs. Animals were euthanized and optical mapping of isolated left and right ventricles electrical activity was performed using the voltage-sensitive dye Di-4-ANEPPS. Expression of selected genes was assessed by quantitative RT-PCR. At 3 months post-surgery, pulmonary artery regurgitation, RV end-diastolic and end-systolic volumes normalized to body surface area were significantly increased in rTOF pigs compared to Sham animals. In rTOF-PPVI animals these parameters were partially reversed and not statistically different from Sham pigs. An action potential prolongation was observed in both the left ventricle and the RV epicardium but not in the endocardium of rTOF pigs. Within the RV epicardium, this prolongation was mainly confined to the anterior side. Interestingly, rTOF-PPVI pigs action potential durations were similar to Sham animals. In line with functional investigations, a large increase in BNP expression was found in rTOF RV compared to Sham pigs (fold change = 34) which was not as pronounced in rTOF-PPVi pigs (fold change = 3) while a lower expression of KCND3 and KCNJ2 was found in rTOF pigs. In our rTOF porcine model, PPVI at an early pathological stage reversed RV dilatation. It also successfully reversed action potential prolongation in the left ventricle and the anterior RV epicardium, and may thus have beneficial effects on the arrhythmic risk.

CMR parameters and CMR-FT in repaired tetralogy of Fallot

BackgroundRepaired tetralogy of Fallot patients develops postoperative complications that are in need for follow-up and re-intervention in some circumstances. CMR myocardial feature tracking is a novel method that allows quantification of bi-atrial and bi-ventricular mechanics of deformation. So our aim is to assess the added value of cardiac magnetic resonance imaging and its advanced feature tracking analysis in evaluation of repaired tetralogy of Fallot patients.ResultsCMR was done with feature tracking post-processing analysis for 56 patients with repaired tetralogy of Fallot and 56 healthy volunteers. The commonest postoperative complications in patients with repaired tetralogy of Fallot are in the following order: pulmonary regurgitation with subsequent right ventricular dilatation and tricuspid regurgitation followed by pulmonary stenosis, right ventricular dysfunction, right ventricular outflow tract dilatation, left ventricular dysfunction, aortic and mitral regurgitation and residual ventricular septal defect. All right ventricular volumes were found to be significantly increased compared to those of the healthy volunteers (p value < 0.001) also left ventricular end-diastolic and end-systolic volumes indexed were found to be increased in those patients compared to healthy volunteers (p value < 0.001). Right and left ventricular function were significantly lower in those patients compared to controls. Bi-ventricular CMR-FT indices and right atrial global longitudinal strain were found to be significantly lower in patients with repaired tetralogy of Fallot compared to controls. Right atrium global longitudinal strain was found to be significantly correlated with right ventricular global longitudinal strain and did not correlate with right ventricular ejection fraction and end-diastolic volume indexed; p value < 0.001, 0.109 and 0.565, respectively. Right ventricular global circumferential strain was found to be significantly increased in patients with right ventricular outflow tract obstruction compared to those without obstruction (− 16.26 ± 4.27% vs. − 12.2 ± 3.78%, respectively). Pulmonary regurgitant volume indexed was found to be significantly related to right ventricle longitudinal strain (p value 0.027).ConclusionBiventricular volumetric measures are increased in patients with repaired tetralogy of Fallot compared to controls; however, feature tracking parameters for both ventricles and right atrium are lower in those patients compared to controls.

Right Ventricular Flow Vorticity Relationships With Biventricular Shape in Adult Tetralogy of Fallot.

Remodeling in adults with repaired tetralogy of Fallot (rToF) may occur due to chronic pulmonary regurgitation, but may also be related to altered flow patterns, including vortices. We aimed to correlate and quantify relationships between vorticity and ventricular shape derived from atlas-based analysis of biventricular shape. Adult rToF (n = 12) patients underwent 4D flow and cine MRI imaging. Vorticity in the RV was computed after noise reduction using a neural network. A biventricular shape atlas built from 95 rToF patients was used to derive principal component modes, which were associated with vorticity and pulmonary regurgitant volume (PRV) using univariate and multivariate linear regression. Univariate analysis showed that indexed PRV correlated with 3 modes (r = −0.55,−0.50, and 0.6, all p < 0.05) associated with RV dilatation and an increase in basal bulging, apical bulging and tricuspid annulus tilting with more severe regurgitation, as well as a smaller LV and paradoxical movement of the septum. RV outflow and inflow vorticity were also correlated with these modes. However, total vorticity over the whole RV was correlated with two different modes (r = −0.62,−0.69, both p < 0.05). Higher vorticity was associated with both RV and LV shape changes including longer ventricular length, a larger bulge beside the tricuspid valve, and distinct tricuspid tilting. RV flow vorticity was associated with changes in biventricular geometry, distinct from associations with PRV. Flow vorticity may provide additional mechanistic information in rToF remodeling. Both LV and RV shapes are important in rToF RV flow patterns.

Le Cœur en Sabot: shape associations with adverse events in repaired tetralogy of Fallot

BackgroundMaladaptive remodelling mechanisms occur in patients with repaired tetralogy of Fallot (rToF) resulting in a cycle of metabolic and structural changes. Biventricular shape analysis may indicate mechanisms associated with adverse events independent of pulmonary regurgitant volume index (PRVI). We aimed to determine novel remodelling patterns associated with adverse events in patients with rToF using shape and function analysis.MethodsBiventricular shape and function were studied in 192 patients with rToF (median time from TOF repair to baseline evaluation 13.5 years). Linear discriminant analysis (LDA) and principal component analysis (PCA) were used to identify shape differences between patients with and without adverse events. Adverse events included death, arrhythmias, and cardiac arrest with median follow-up of 10 years.ResultsLDA and PCA showed that shape characteristics pertaining to adverse events included a more circular left ventricle (LV) (decreased eccentricity), dilated (increased sphericity) LV base, increased right ventricular (RV) apical sphericity, and decreased RV basal sphericity. Multivariate LDA showed that the optimal discriminative model included only RV apical ejection fraction and one PCA mode associated with a more circular and dilated LV base (AUC = 0.77). PRVI did not add value, and shape changes associated with increased PRVI were not predictive of adverse outcomes.ConclusionPathological remodelling patterns in patients with rToF are significantly associated with adverse events, independent of PRVI. Mechanisms related to incident events include LV basal dilation with a reduced RV apical ejection fraction.

Flow vorticity relationships with right ventricular geometry in adult tetralogy of Fallot

Abstract Background Repaired tetralogy of Fallot adults (rToF) undergo right ventricular (RV) remodeling, in part due to volume overload of residual pulmonary regurgitation volume (PRV). Time-resolved phase-contrast cardiac magnetic resonance imaging (4D Flow MRI) enables the qualitative and quantitative measurement of altered blood flow patterns, including vorticity. Cardiac atlases allow for complex three-dimensional heart shapes to be expressed as morphometric scores. Those scores show the extent of geometrical shift and can help explore uncharted relationships between vorticity and architecture. Purpose We aimed to quantify vorticity, incorporating deep learning to enhance 4D Flow data, and correlate this with global cardiac parameters and morphometric scores. Methods 12 Adult rToF patients and 10 age-matched controls underwent 4D flow MRI and cine imaging. RV interventricular vorticity was calculated for outflow and inflow tracts. EDV, ESV and SV were computed from cines which were also used to build three-dimensional shape models. The biventricular models were projected onto an atlas generated from 95 rToF patients, and twenty-one principal component analysis shape modes were correlated with cardiac metrics and vorticity to identify global shape variations. Association between biventricular shape and vorticity was further analysed using multivariate multiple regression models. Results Strong correlation was found between PRV and the right ventricular outflow tract (RVOT) vorticity. PRV and RVOT vorticity both correlated with the same 3 shape modes (r=−0.55, −0.50 and 0.6 (p&amp;lt;0.05) respectively for PR and r=0.63, −0.82 and 0.60 (p&amp;lt;0.05) respectively for vorticity) i.e., the RV dilates with an increase in basal bulging, apical bulging and tricuspid annulus tilting with more severe regurgitation, as well as a smaller LV, and a paradoxical movement of the septum (Figure 1). However, RV vorticity correlated with 2 modes that did not correlate with PRV, (r=−0.62, −0.69, p&amp;lt;0.05). With higher vorticity the RV was longer, increased tilting of the tricuspid annulus and an increased basal bulge around the tricuspid area. The multivariate analysis model demonstrated that higher vorticity was associated with displacement of the pulmonary valve and change in the RVOT length and direction. A septal displacement towards the left ventricle was observed and increased apical flatness of the RV (Figure 1). Qualitatively, vorticity in rToF group was more heterogeneous than controls (Figure 2). Conclusions Vorticity is a novel marker based on the influence of blood motion providing new insight into early diagnosis and prognosis of cardiac disease. This is the first study to examine the relationships between vorticity and regional RV shape changes in rToF. Mode associations with vorticity were different to associations with PRV. More longitudinal studies are required for standardization of change in vorticity with the disease process. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): The New Zealand heart foundation Mode variations and morphometric modelVorticity visualization and analysis

Right-left ventricular shape variations in tetralogy of Fallot: associations with pulmonary regurgitation

BackgroundRelationships between right ventricular (RV) and left ventricular (LV) shape and function may be useful in determining optimal timing for pulmonary valve replacement in patients with repaired tetralogy of Fallot (rTOF). However, these are multivariate and difficult to quantify. We aimed to quantify variations in biventricular shape associated with pulmonary regurgitant volume (PRV) in rTOF using a biventricular atlas.MethodsIn this cross-sectional retrospective study, a biventricular shape model was customized to cardiovascular magnetic resonance (CMR) images from 88 rTOF patients (median age 16, inter-quartile range 11.8–24.3 years). Morphometric scores quantifying biventricular shape at end-diastole and end-systole were computed using principal component analysis. Multivariate linear regression was used to quantify biventricular shape associations with PRV, corrected for age, sex, height, and weight. Regional associations were confirmed by univariate correlations with distances and angles computed from the models, as well as global systolic strains computed from changes in arc length from end-diastole to end-systole.ResultsPRV was significantly associated with 5 biventricular morphometric scores, independent of covariates, and accounted for 12.3% of total shape variation (p < 0.05). Increasing PRV was associated with RV dilation and basal bulging, in conjunction with decreased LV septal-lateral dimension (LV flattening) and systolic septal motion towards the RV (all p < 0.05). Increased global RV radial, longitudinal, circumferential and LV radial systolic strains were significantly associated with increased PRV (all p < 0.05).ConclusionA biventricular atlas of rTOF patients quantified multivariate relationships between left–right ventricular morphometry and wall motion with pulmonary regurgitation. Regional RV dilation, LV reduction, LV septal-lateral flattening and increased RV strain were all associated with increased pulmonary regurgitant volume. Morphometric scores provide simple metrics linking mechanisms for structural and functional alteration with important clinical indices.

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

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

Pulmonary Insufficiency: Advantage of Pulmonary Regurgitation Volume Versus Pulmonary Regurgitation Fraction in a Congenital Heart Disease Mixed Population.

The objective of this study was to compare the use of pulmonary regurgitation volume (PRV) or indexed PRV (PRVi) with that of pulmonary regurgitation fraction (PRF) in the assessment of patients with pulmonary regurgitation (PR) undergoing cardiac magnetic resonance (CMR) imaging. CMR of 176 patients with PR were retrospectively evaluated. Their right ventricular diastolic (end-diastolic volume index [EDVi]) and systolic (end-systolic volume index) volume indexes, stroke volume, and ejection fraction were obtained from cine CMR sequences, whereas phase-contrast flow sequences were analyzed to obtain PRV, PRVi, and PRF. Patients were divided into subgroups, according to underlying pathology and according to PR severity. Correlations between PRV or PRF and RV parameters were studied through Spearman ρ, both in the main group and subgroups. Follow-up examinations were analyzed, and correlations between PRV or PRF from the first CMR examination and volume data from the second were calculated. Tetralogy of Fallot was the main setting of PR (98/179). Overall, EDVi strongly correlates with PRV (ρ=0.592, P<0.001) than with PRF (ρ=0.522, P<0.001), and end-systolic volume index strongly correlates with PRV (ρ=0.454, P<0.001) and PRF (ρ=0.406, P <0.001). As regards subgroup analysis, in moderate or severe PR patients, EDVi strongly correlates (P=0.043) with PRV (ρ=0.499, P<0.001) than with PRF (ρ=0.317, P<0.001). Follow-up EDVi correlates with PRV (ρ=0.450, P=0.031), but not with PRF. Especially when assessing moderate to severe PR, PRV and PRVi may be better indicators of right ventricular dysfunction than PRF. Moreover, PRV may be a predictor of worsening RV dilation.

Severe pulmonary regurgitation in adolescents with tetralogy of Fallot leads to increased longitudinal strain

ObjectivesPostoperative patients with tetralogy of Fallot (TOF) are often compromised by chronic pulmonary regurgitation and chronic right ventricular volume load. We sought to determine whether pulmonary regurgitation (PR) would affect right and left ventricle (RV and LV) strain.Materials and methodsThis cross-sectional analysis included 40 patients who had TOF with surgical repair, with an average follow-up period of 11.8 ± 3.0 years. Altogether, 44 healthy volunteers with similar age and gender distribution were recruited. A cardiovascular magnetic resonance imaging study with feature tracking analysis was performed on all patients and controls.ResultsRV peak longitudinal strain was increased in TOF patients with PR > 30 ml/m2 when compared to those with PR < 30 ml/m2 (− 22.5% ± 2.7% vs − 19.7% ± 3.5%, p = 0.018) and controls (p = 0.007). PR volume correlated with peak RV longitudinal strain (R = − 0.37, p = 0.030) and peak RV longitudinal strain rate (systolic: R = 0.37, p = 0.03; diastolic: R = 0.39, p = 0.021). The peak RV circumferential strain, from base to apex, increased more than in healthy controls (apex-base difference 7.6% ± 4.2% vs 3.3% ± 2.4%, p < 0.0001).ConclusionsPediatric patients with TOF and a severe pulmonary regurgitation show an enhanced longitudinal strain when compared to patients with milder regurgitation or to control subjects. In addition, mean RV circumferential strain of the patients is significantly enhanced compared to healthy individuals.

TRICUSPID VALVE (TV) LEAFLET EXPANSION IS THE MAIN ADAPTIVE CHANGE TO MAINTAIN COMPETENCY: A THREE-DIMENSIONAL ECHOCARDIOGRAPHY (3DE) STUDY IN A NOVEL CHRONIC RIGHT VENTRICULAR (RV) PRESSURE AND VOLUME LOADED PIGLET MODEL

Tricuspid valve regurgitation (TR) develops in 25-35% of children with hypoplastic left heart syndrome (HLHS), a risk factor for morbidity and mortality. Surgical strategies for TR in HLHS are modest in success and durability, therefore warrants improved understanding and innovation. We developed a novel piglet model simulating infant HLHS RV physiology to study TV adaptation to chronic increased preload and afterload. We hypothesize that TV competency is maintained by adaptive rapid leaflet expansion despite annular dilation. Sixteen piglets at 4-5weeks of age (maturity equivalent to infants) underwent left thoracotomy. Intervention piglets (IP, n=8) had their pulmonary valve torn to produce moderate to severe pulmonary regurgitation (volume loading) and pulmonary artery band placed to increase RV pressure. Control piglets (CP, n=8), age and gender matched, had sham surgery. Following a 4-week recovery, all piglets underwent hemodynamic assessment and 3DE of TV. We assessed TV annulus and leaflet geometry in mid-systole using a custom 3DE software (MATLAB). Ex-vivo TV total leaflet area was measured. Comparisons between IP and CP were made using Student t-test with significance at p < 0.05. Values were expressed as mean (standard deviation). IP had significant pulmonary regurgitation (mean PR reverse/forward velocity time integral ratio 0.68 (0.09)) and mean RV systolic pressure 77.9% of systemic pressure, reflected in thicker RV free wall and anterior papillary muscle, consistent with an effective model. IP and CP were similar in weight and TR grade. IP TV annulus were larger (p=0.02), more circular (p=0.03) and leaflets more tethered (p=0.02) with 43% larger total leaflet area (p=0.01) [see Table]. Greatest expansion was seen in the posterior leaflet (p=0.01). 3DE TV total leaflet area correlated with ex-vivo TV pathologic specimen area (r=0.63, p=0.02). Following chronic exposure to increased RV preload and afterload, there is TV annular dilation and likely unchanged sub-valve apparatus, resulting in leaflet tethering. In-vivo 3DE identified rapid leaflet expansion as the main adaptive change to maintain competency from detrimental remodeling. Further research into modulation of TV leaflet growth may be important for understanding TV failure in HLHS.

Assessment of Disease Progression in Patients with Repaired Tetralogy of Fallot Using Cardiac Magnetic Resonance Imaging

Background: Tetralogy of Fallot (ToF) is the commonest cyanotic congenital heart disease with a long term survival of over 85%, making adult survivors an ever growing population. Late pulmonary outflow tract and pulmonary valve post-operative complications are frequent, leading to risk of right ventricular (RV) failure and arrhythmias related sudden death. Timing of pulmonary valve intervention remains challenging, with early intervention being balanced against the risk with the number of interventions over a patient's life time. Imaging frequency for correct timing of intervention is unclear, largely based around estimation of rate of RV dilatation. Aim: To perform a systematic review of the use of cardiac magnetic resonance imaging (CMR) to predict disease progression (RV dilatation, dysfunction, or adverse clinical event) in patients with repaired tetralogy of Fallot (rToF), and use the information to determine the optimal interval for follow-up CMR. Methods: PubMed searched from inception until 30th April 2018 for relevant articles. Results: 25 studies identified. Right and left ventricular volumes and function have proven significance in predicting timing for intervention. Severity of pulmonary valve regurgitation has also been shown to predict progression of RV dilatation, with pulmonary valve regurgitant volume appearing more predictive than regurgitant fraction. Optimal frequency of clinical and imaging review in adult patients with rToF remains uncertain. Conclusion: The optimal timing of repeat cardiac imaging in rToF remains controversial, with a three year schedule for repeat CMR appearing reasonable in asymptomatic patients. Large prospective studies will provide important information to guide clinical decision in this area.

4D flow CMR analysis in repaired tetralogy of Fallot: Where we are and where we are going

4D flow cardiovascular magnetic resonance (4D flow CMR) enable time-varying and multidirectional comprehensive retrospective analysis. However, this imaging modality must prove its relevance. After tetralogy of Fallot surgical repair, pulmonary valve function and right ventricle (RV) volumes are carefully followed. We investigate reliability of 4D flow CMR to measure these parameters compared to gold-standard 2D CMR. Twenty patients with rTOF and 5 healthy controls (mean age 29 ± 13 years, mean height 169 ± 7 cm, mean weight 66.2 ± 13.4 kg) underwent RV volumes and pulmonary regurgitation analysis by 2D CMR and 4D flow CMR using a clinical 1.5 T MRI scanner (GE; GE Healthcare, Milwaukee, WI, USA). Mean 4D flow acquisition time was 8.0 ± 1.8 min, whereas conventional 2D CMR was 39 ± 7.2 min ( P < 0.0001). Linear regression analysis shows a good correlation between 2D CMR and 4D flow CMR for RV stroke volume (SV) (r 2 = 0.89, P < 0.0001), end-diastolic RV volume (r 2 = 0.93, P < 0.0001), pulmonary regurgitation volume (r 2 = 0.94, P < 0.0001) and pulmonary regurgitation fraction (r 2 = 0.89, P < 0.0001). Mean bias [−1.96SD; +1.96SD] was 17.5 mL [4.75; 30.15] for RVSV, −8.4 mL [−17.04; 0.16] for end diastolic RV volume, 1.5 mL [−2.17; 5.23] for pulmonary regurgitation volume and 0.7% [−0.8; 2.2] for pulmonary regurgitation fraction by Bland–Altman analysis. Using 4D flow CMR, linear regression analysis showed a good correlation between RV SV and pulmonary valve systolic ejection volume (r 2 = 0.55, P < 0.0001), and between systemic and pulmonary flow (r 2 = 0.90, P < 0.0001). Mean bias was 22.7 mL [6.4; 39.0] for SV, and −0.06 mL [−0.18; 0.06] for systemic and pulmonary flow by Bland–Altman analysis. Vortex in the pulmonary artery trunk were observed in all cases of rTOF patients and limited analysis of pulmonary artery regurgitation flow. 4D flow imaging may be a clinically relevant alternative to 2D CMR in rTOF, providing faster and reliable data.

Long-term follow-up in adults after tetralogy of Fallot repair

BackgroundTetralogy of Fallot (ToF) is the most common cyanotic congenital heart disease and the population of ToF repair survivors is growing rapidly. Adults with repaired ToF develop late complications. The aim of this study was to describe and analyze long-term follow-up of patients with repaired ToF.MethodsThis is a retrospective cohort study. Consecutive 83 patients with repaired ToF who did not undergo pulmonary valve replacement were included. Mean age of all patients was 30.5 ± 10.7. There were 49 (59%) male. Patients were divided into two groups according to the time since the repair (< 25 years and ≥ 25 years). The electrocardiographic (ECG), cardiopulmonary exercise testing (CPET), echocardiographic and cardiac magnetic resonance (CMR) data were reviewed retrospectively.ResultsIn CPET values were not significantly different in the two groups. In CMR volumes of left and right ventricles were not significantly different in the two groups. There were no differences between the groups in ventricular ejection fraction, mass of ventricles, or pulmonary regurgitation fraction. Among all the patients, ejection fraction and left and right ventricle mass, indexed pulmonary regurgitation volume measured by CMR did not correlate with the time since repair. In ECG among all the patients, ejection fraction of the RV, measured in CMR, negatively correlated with QRS duration (r = − 0.43; p < 0.001). There was a positive correlation between QRS duration and end diastolic volume of the RV (r = 0.30; p < 0.02), indexed end diastolic volume of the RV (r = 0.29; p = 0.04), RV mass (r = 0.36; p < 0.001) and left ventricle mass (r = 0.26; p = 0.04).ConclusionLong-term survival and clinical condition after surgical correction of ToF in infancy is generally good and the late functional status in ToF – operated patients could be excellent up to 25 years after the repair. QRS duration could be an utility and easy factor to assessment of right ventricular function.Trial registrationThe study protocol was approved by the local Ethics Committee. Each participant provided informed consent to participate in the study (license number 122.6120.88.2016 from 28.04.2016).

Importance of Non-invasive Right and Left VentricularVariables on Exercise Capacity in Patients with Tetralogy of Fallot Hemodynamics.

Good quality of life correlates with a good exercise capacity in daily life in patients with tetralogy of Fallot (ToF). Patients after correction of ToF usually develop residual defects such as pulmonary regurgitation or stenosis of variable severity. However, the importance of different hemodynamic parameters and their impact on exercise capacity is unclear. We investigated several hemodynamic parameters measured by cardiovascular magnetic resonance (CMR) and echocardiography and evaluated which parameter has the most pronounced effect on maximal exercise capacity determined by cardiopulmonary exercise testing (CPET). 132 patients with ToF-like hemodynamics were tested during routine follow-up with CMR, echocardiography and CPET. Right and left ventricular volume data, ventricular ejection fraction and pulmonary regurgitation were evaluated by CMR. Echocardiographic pressure gradients in the right ventricular outflow tract and through the tricuspid valve were measured. All data were classified and correlated with the results of CPET evaluations of these patients. The analysis was performed using the Random Forest model. In this way, we calculated the importance of the different hemodynamic variables related to the maximal oxygen uptake in CPET (VO2%predicted). Right ventricular pressure showed the most important influence on maximal oxygen uptake, whereas pulmonary regurgitation and right ventricular enddiastolic volume were not important hemodynamic variables to predict maximal oxygen uptake in CPET. Maximal exercise capacity was only very weakly influenced by right ventricular enddiastolic volume and not at all by pulmonary regurgitation in patients with ToF. The variable with the most pronounced influence was the right ventricular pressure.

Impact of residual right ventricular outflow tract obstruction on biventricular strain and synchrony in patients after repair of tetralogy of Fallot: a cardiac magnetic resonance feature tracking study.

Residual right ventricular outflow tract (RVOT) obstruction (RVOTO) is considered beneficial in patients after repair of tetralogy of Fallot (TOF) although underlying mechanisms are unknown. We sought to elucidate differences in myocardial strain and dyssynchrony parameters in patients after TOF repair with and without residual RVOTO using cardiovascular magnetic resonance (CMR) feature-tracking (CMR-FT) analysis. Fifty-four patients (mean age 16.4 ± 8.4 years) were assessed by CMR 14.2 ± 7.3 years after repair of TOF. Residual RVOTO on echocardiography was defined as a peak systolic RVOT gradient >25 mmHg and was present in 27 patients (no RVOTO in n = 27 patients). Right ventricular (RV) and left ventricular (LV) strain measurements were performed using CMR-FT software. The two groups were well matched for age at CMR scan, time and type of surgical repair. There was no difference in the degree of pulmonary regurgitation (PR) and RV end-diastolic volume. Patients with RVOTO showed significant higher RV circumferential strain (CS) (P = 0.02) and RV radial strain (RS) (P = 0.02) values, whereas RV longitudinal strain (LS) did not differ between the two groups (P = 0.39). The degree of RVOTO showed a significant correlation with RV-CS (r = 0.37; P = 0.006) and RV-RS (r = 0.30; P = 0.03) while RV-LS was unrelated to RVOTO (r = 0.06; P = 0.68). Significant relationships between RV and LV strain parameters were only found in the RVOTO group. Interventricular dyssynchrony was significantly higher in the group without RVOTO (P = 0.03) while LV-LS (P = 0.03) and LV intraventricular synchrony (P = 0.05) were impaired in the RVOTO group. In patients after TOF repair, residual RVOTO seems to preserve RV strain and results in stronger RV-LV interactions and less interventricular dyssynchrony and may therefore possess an early protective effect on RV remodelling. However, the potential negative impact of residual pulmonary stenosis on LV strain and intraventricular synchrony needs further investigation.

Mechanisms of right ventricular electromechanical dyssynchrony and mechanical inefficiency in children after repair of tetralogy of fallot.

Right bundle branch block and right ventricular (RV) dysfunction are common after tetralogy of Fallot repair (rTOF). We hypothesized that right bundle branch block is associated with specific RV mechanical dyssynchrony and inefficient contraction. We studied rTOF children and age-matched controls. QRS duration and morphology were assessed. RV mechanical dyssynchrony, indicated by early septal activation (right-sided septal flash), RV lateral wall prestretch/late contraction, postsystolic shortening, and intraventricular delay were analyzed using 2-dimensional strain echocardiography. Peak oxygen consumption reflected exercise capacity. Pulmonary regurgitation and RV volumes were assessed by MRI. Forty-six rTOF patients and 46 controls were studied. Ninety-three percent of rTOF patients demonstrated a right-sided septal flash with simultaneous RV basal lateral wall prestretch/late activation. The RV basal segment was the most delayed in onset (115 [0-194] versus 35 [0-96] ms) and termination (462 [369-706] versus 412 [325-529] ms) of longitudinal shortening, with postsystolic shortening. QRS duration correlated with RV basal time to onset and peak shortening (P<0.05). Intra-RV delay was higher in rTOF (P<0.05) in association with RV dilatation (r=0.33; P=0.04). In rTOF, RV mechanics were inefficient, with prestretch and postsystolic shortening comprising 15±11% and 16±9% of total shortening, respectively. A composite parameter of electric and mechanical dyssynchrony correlated with RV end-diastolic volume (r=0.39; P=0.03). Typical electromechanical dyssynchrony associated with mechanical inefficiency, regional dysfunction, and RV dilatation is common in rTOF children, possibly contributing to progressive RV dysfunction. The potential of cardiac resynchronization in appropriate patients requires further study.

Atrial Mechanics after Surgical Repair of Tetralogy of Fallot

Ventricular diastolic dysfunction in patients with repaired tetralogy of Fallot (TOF) may affect atrial mechanics. This study aimed to explore right atrial (RA) and left atrial (LA) mechanics in repaired TOF patients and their relationship with ventricular diastolic function. Fifty-four patients (36 males), aged 17.8 ± 8.3 years, who had undergone TOF repair at 3.9 ± 3.3 years and 40 healthy subjects aged 16.9 ± 6.3 years (P = 0.57) were studied. Right and LA peak positive, peak negative, and total strain, strain rate at ventricular systole (SRs ), early diastole (SRed ), and atrial contraction (SRac ), and electromechanical delay were determined using speckle tracking echocardiography (STE). Ventricular diastolic function was assessed by tissue Doppler imaging and STE. Ventricular volumes and pulmonary regurgitant volume were derived from 3D echocardiography. Compared with controls, patients had significantly lower RA and LA peak positive and total strain, SRs , SRed , and SRac (all P < 0.001). The timing of RA (178 ± 33 msec vs. 152 ± 17 msec, P < 0.001) and LA (170 ± 32 msec vs. 152 ± 24 msec, P = 0.006) electromechanical coupling (EMC) was significantly longer in patients than in controls. The RA total strain, SRs , SRed , SRac , and EMC correlated positively with corresponding LA parameters (all P < 0.001). The RA and LA total strain and SRed were associated positively with diastolic annular velocities and strain rates of respective ventricles (all P < 0.05). The LA SRed correlated negatively with pulmonary regurgitant volume (r = -0.33, P = 0.016) and RV end-diastolic volume (r = -0.33, P = 0.015). Mechanics of both atria are impaired in patients after repair of TOF and are associated with diastolic performance of the respective ventricles.

The relationship between longitudinal, lateral, and septal contribution to stroke volume in patients with pulmonary regurgitation and healthy volunteers

Septal systolic motion is towards the left ventricle (LV) in healthy hearts. Patients with pulmonary regurgitation (PR) and right ventricular (RV) volume overload have systolic septal motion toward the RV. This may affect the longitudinal contribution from atrioventricular plane displacement (AVPD) and septal and lateral contribution to stroke volume (SV). The study aimed to quantify these contributions to SV in patients with PR. Cardiac magnetic resonance imaging was used for assessment of cardiac volumes. Patients (n = 30; age 9-59 yr) with PR due to surgically corrected tetralogy of Fallot and 54 healthy controls (age 10-66 yr) were studied. Longitudinal contribution to RVSV was 47 ± 2% (means ± SE) in patients with PR and 79 ± 1% in controls (P < 0.001). Lateral contribution to RVSV and LVSV was 40 ± 1 and 62 ± 2% in patients and 31 ± 1 and 36 ± 1% in controls (P < 0.001 for both). Septal motion contributed to RVSV by 8 ± 1% in patients and by 7 ± 1% to LVSV in controls (P < 0.001). PR patients have decreased longitudinal contribution to RVSV and increased lateral pumping, resulting in larger outer volume changes and septal motion towards the RV. The changes in RV pumping physiology may be explained by RV remodeling resulting in lower systolic inflow of blood into the right atrium in relation to SV. This avoids the development of pendulum volume between the caval veins and right atrium, which would occur in PR patients if longitudinal contribution to SV was preserved. Decreased AVPD suggests that tricuspid annular excursion, a marker of RV function, is less valid in these patients.

Determinants of right heart size and function in repaired Tetralogy of Fallot

Results RV EDV was positively associated with pulmonary regurgitant (PR) volume (b 0.59, p < 1e), tricuspid regurgitant (TR) volume (b 0.24, p < 1e), body surface area (b 0.08, p < 1e), and age (b 0.20, p < 1e). Significant residual outflow tract stenosis (b -0.10, p = 0.01), branch pulmonary artery stenosis (b -0.09, p = 0.02) and RV EF (b -0.38, p < 1e) were negatively associated with RV EDV (Model, R = 0.81). Initial palliation with a Blalock-Taussig Shunt (b -0.234, p = 0.0001) was associated with lower RV EF. TR volume was associated with higher RV EF (b -0.13, p = 0.03), (Model, R = 0.26); residual outflow tract obstruction was not associated with RV EF. RV ESV had similar associations to RV EDV, except residual outflow tract obstruction and branch PA stenosis were not associated, and RVEF was the most influential covariate (Model, R = 0.83).