Function In Tetralogy Of Fallot Research Articles

Abstract 12897: Automated Assessment of Left Ventricular Function in Tetralogy of Fallot - A Machine Learning Approach

Introduction: Congenital heart disease (CHD) is associated with significant cardiac anatomic and functional variability. This study tests the implementation and validation of a convolutional neural network algorithm (EchoNet-Dynamic) on a pediatric dataset via a transfer learning approach. We compare the echocardiographic systolic function measure, left ventricular ejection fraction (LVEF), with CMR as the gold standard. Methods: Patients ages 1-18 (44% female) who underwent a transthoracic echocardiographic evaluation and CMR for repaired Tetralogy of Fallot (TOF) were divided into 2 groups of EF < and >40%. 406 (2D-A4C views) videos with LVEF calculated using Bullet and Simpson method were identified. MRI EF as a ground truth label was compared with predicted EF data. Inference weights were derived from EchoNet-Dynamic and the weights from re-training the model on pediatric data. Correlation statistics were computed. The metrics included mean absolute error (MAE), root mean squared error (RMSE), and coefficient of determination (R2). Results: The R2 of actual vs predicted was 0.83 (0.71-0.89) with an MAE of 3.55. The predicted EF vs MRI EF resulted in an R2 of 0.48 and an MAE of 6.39 (Figure 1 a-c). Bland-Altman analysis between actual vs predicted EF estimates LVEF (bias = 1.64%) with 95% limits of agreement of -7.80% to 11.09%. MRI EF vs predicted values, the model estimates LVEF (bias = -3.12%) with 95% limits of agreement of -18.71% to 12.48%. The smaller body surface area and ages correlated with better model performance in both groups. Conclusions: EchoNet-Dynamic trained on a pediatric data set can accurately predict EF and this validates the model’s performance on a distinct CHD population. The predicted EF accurately compares with the MRI assessment. EchoNet Dynamic can be employed via a transfer learning method for automated real-time evaluations of cardiac function in CHD patients with compromised ventricular function and complex anatomical phenotypes.

Right Atrial Function Changes in Tetralogy of Fallot

Background: There is limited information on right atrial (RA) function in the congenital heart defects. RA volume and function may give insight into the right ventricle (RV) diastolic function. We sought to assess RA function in tetralogy of Fallot (TOF) patients prior to and after complete surgical repair. Methods: Infants with TOF prior to complete repair were included for retrospective chart review and offline analysis of 2-dimensional echocardiograms (echo) before …

Abstract 17266: Right Atrial Volumes Changes in Tetralogy of Fallot

Introduction & Hypothesis: There is limited information on right atrial (RA) function in the congenital heart defects. RA volume and function may give insight into the right ventricle (RV) diastolic function. We sought to assess RA function in tetralogy of Fallot (TOF) patients prior to and after complete surgical repair. Methods: Infants with TOF prior to complete repair were included for retrospective chart review and offline analysis of 2-dimensional echocardiograms (echo) before and after surgical repair. RA phasic volumes and stroke volumes were calculated. All volumes were indexed to body surface area. Results: There were 40 infants with TOF (45% females), of which 70% had pulmonary stenosis, 30% pulmonary atresia. Roughly 85% and 60% had 3, or more, echo available pre- and postoperatively. Table 1 (attached) shows the patient characteristics and phasic RA volumes. The indexed RA phasic volumes were in normal range in initial echo prior to surgery. We used normal index RA phasic volumes published by European Society of Echocardiography. There was the increasing trend of indexed RA phasic volume on follow up echo immediately before TOF repair. These phasic volumes continued to remain elevated after complete surgical repair (Table 1). Trends in RA stroke volumes for all available echos before and after surgery were modeled using a population-averaged model with an exchangeable within-panel correlation structure (Figure 2), showing no statistically significant difference after surgery. But there was statistical significance noted in RA ejection fraction. Please see attached image for statistical analysis and results of the study. Conclusions: The indexed RA phasic volumes in children with TOF are normal initially and increases before TOF repair and it continued to increase after TOF repair. The increase RA phasic volumes suggest RV diastolic dysfunction similar to the findings of LA phasic volumes and left ventricular diastolic dysfunction. Our findings indicate slow worsening RV diastolic function in patients with TOF after surgical repair. RA volume and function can be the novel marker to diagnose and monitor right ventricular diastolic dysfunction.

Longitudinal Changes in Right Ventricular Function in Tetralogy of Fallot in the Initial Years after Surgical Repair

Right ventricular (RV) dysfunction is associated with adverse long-term outcomes in patients with tetralogy of Fallot. Little is known about RV function in the first years after surgical repair. The aim of this study was to investigate perioperative changes in myocardial deformation using global longitudinal strain. A retrospective analysis of patients with surgically repaired tetralogy of Fallot was performed. Global longitudinal peak systolic RV strain was measured on early postoperative echocardiograms, two subsequent postoperative echocardiograms through 2years postoperatively, and preoperative echocardiograms, when available. Preoperative and late follow-up strain was compared with strain in 0- to 8-month-old and 1- to 4-year-old control subjects, respectively. Forty-seven patients were included. Compared with postoperative strain (7±7days postoperatively), strain at follow-up 1 (8.3±4months postoperatively) was significantly improved (-12.3±3.3% vs -18.8±2.5%, P<.001), with no additional improvement 23.2±6months postoperatively (-18.8±2.5% vs -19.8±3.1%, P=.12). Postoperative strain was worse than preoperative strain (n=25, -12.5±3.6% vs -18.4±2.9%, P<.001). Compared with control subjects, preoperative strain was similar (-19.3±3.8% vs -18.4±2.9%, P=.30), though late follow-up strain was significantly worse (-27.7±2.8% vs -19.8±3.1%, P<.001). RV global longitudinal strain worsens in the early postoperative period following surgical repair of tetralogy of Fallot but recovers through 2 postoperative years. Despite recovery to preoperative values, the presence of RV dysfunction compared with control subjects suggests that long-term dysfunction may begin early. The trajectory of RV dysfunction through the later years needs further study.

Long-term outcomes following transatrial versus transventricular repair on right ventricular function in tetralogy of Fallot.

Outcomes after repair of tetralogy of Fallot (TOF) are good with either a transventricular (TV) or transatrial (TA) approach. We sought to determine if there is a relationship between the TV or TA approach and right ventricular (RV) function, and the role of residual pulmonary regurgitation (PR) on the long-term outcomes. This was a retrospective cohort multicentric study on survivors after surgical repair of TOF (TA versus TV approach, ±transannular patch) between 1990 and 2004. All patients underwent magnetic resonance imaging to assess RV volume, function, and PR. Patients were matched for length of follow-up and age. Clinical adverse events were retrieved from institutional databases. Seventy-nine patients (TA/TV = 37/42, median age 0.3 and 1.0 yrs, respectively) were included. At a median follow-up of 16.6 years (12.5-20.3), there were no differences in freedom from reintervention (either catheter or surgical), RV volumes, function, and PR between the TA and TV groups. Pulmonary valve (PV) replacement was significantly less frequent in the TA subgroup (P = 0.033) and patients with a preserved PV showed significantly lower RV volumes and less adverse events at follow-up. There is no significant difference in RV volumes and function between the TA and TV. However, the TA approach seems to be protective against PV replacement in the long-term. When PV is not preserved at repair, residual pulmonary regurgitation is a significant cause of late RV dysfunction and dilation, and is associated with a higher rate of late adverse events.

What Echocardiographic Measure Should Be Used to Assess Right Ventricular Function in Tetralogy of Fallot?

What Echocardiographic Measure Should Be Used to Assess Right Ventricular Function in Tetralogy of Fallot?

Mechanism of aortic root dilation and cardiovascular function in tetralogy of Fallot.

The aortic root dilation in tetralogy of Fallot (TOF) is a long-term clinical problem, because a severely dilated aorta can lead to aortic regurgitation, dissection, or rupture, which can be fatal, necessitating surgical intervention. The details of the mechanism of aortic root dilation, however, are unclear. We have shown that aortic stiffness is increased in patients with repaired TOF, and may mirror the histological abnormality of elastic fiber disruption and matrix expansion. This aortic stiffness is related closely to the aortic dilation, indicating that aortic stiffness may be a predictor of outcome of aortic dilation. Furthermore, the aortic volume overload is a very important determinant of aortic diameter in TOF patients before corrective surgery. In addition, a chromosomal abnormality and the transforming growth factor-β signaling pathway, a major contributor to aortic dilation in Marfan syndrome, also affect this mechanism. In this way, aortic dilation in TOF patients is suggested to be a multifactorial disorder. The aim of this review was therefore to clarify the mechanism of aortic dilation in TOF, focusing on recent research findings. Studies linking histopathology, mechanical properties, molecular/cellular physiology, and clinical manifestations of aortic dilation facilitate appropriate treatment intervention and improvement of long-term prognosis of TOF.

Three-dimensional changes in regional right ventricular curvature and function in tetralogy of fallot

Background Many patients with Tetralogy of Fallot (TOF) have residual pulmonic stenosis and/or regurgitation after surgical repair, leading to maladaptive right ventricular (RV) remodeling. Cardiovascular magnetic resonance (CMR) is currently the gold standard for evaluating RV size and function. Analysis of regional volume and three-dimensional (3D) curvature of the RV from CMR images may provide new insights into the remodeling process. The aim of this study is to describe RV remodeling by characterizing regional endocardial surface curvature and function in patients with TOF. Methods CMR (1.5T Philips Achieva) was performed in subjects with repaired TOF (N=17, age range 9-53 years) and healthy volunteers (N=10, age range 23-43 years). The RV end-diastolic and end-systolic endocardial surfaces were manually segmented from a contiguous stack of short axis cine slices to construct a 3D model using custom software (figure). This model was used to measure regional volume and ejection fraction for the RV inflow, outflow, and trabecular regions. Local endocardial surface curvature was displayed on a color map of the 3D volume surface and regional curvature was calculated for the RV inflow, outflow, trabecular, free wall, and septal segments. The values for curvature were indexed to volume to remove the influence of volume between regions. The parameters from individuals with TOF were compared to those acquired from the healthy volunteers. Results As shown in the table, individuals with TOF had larger global RV volume and reduced ejection fraction when compared to controls. The trabecular region had relatively preserved ejection fraction, despite exhibiting the most enlargement. Conversely, the outflow and inflow regions had greater reductions in ejection fraction but only mild enlargement. The Trabecular region enlargement coincided with increased regional curvature, which was not as striking in the inflow and outflow regions. Those with TOF had higher overall free wall curvature. Septal curvature in TOF patients was higher (slightly convex) compared to controls (slightly concave). Global curvature, combining all septal and free wall regions, was higher in TOF patients. Conclusions Using analysis of RV 3D regional curvature and volumes from CMR images, we show that individuals with repaired TOF have regional variation in RV remodeling and function. Further evaluation is required to understand the clinical implications of this variable remodeling.

Quantifying Regional Right Ventricular Function in Tetralogy of Fallot

Right ventricular (RV) function is notoriously difficult to quantify. Patients with tetralogy of Fallot (TOF) have decreased systolic performance. We measure regional RV performance using MRI with 1-dimensional myocardial tissue tagging. By tagging cine-MRI in two views, we measured regional shortening in 12 regions throughout the RV. We image 32 pediatric patients: 21 normal patients and 11 patients with repaired TOF. We establish a normal range for each RV region. TOF patients have decreased shortening on a region-by-region basis. We conclude that regional RV performance can be measured using this technique, and that decreased performance can be demonstrated in TOF patients.

Quantification of regional right and left ventricular function by ultrasonic strain rate and strain indexes after surgical repair of tetralogy of fallot

The quantification of regional myocardial function in tetralogy of Fallot (TOF) by conventional M-mode and 2-dimensional echocardiography is difficult because of the complex right ventricular (RV) and altered left ventricular (LV) geometry. In 30 asymptomatic postoperative TOF patients (aged 4 to 16 years) with a low pressure in the right ventricle and with varying degrees of pulmonary regurgitation and in 30 aged-matched healthy children, the ultrasonic-derived regional deformation parameters peak systolic strain rate (SR) and systolic strain (ϵ) were acquired from ventricles and compared. In TOF RV free walls, SR, and ϵ were reduced in the basal, mid-, and apical segments and averaged –1.5 ± 0.6 second−1 for SR and –22 ± 8% for ϵ, respectively (p <0.001 vs normals). Peak systolic SR of the basal RV free wall correlated significantly with the QRS duration of the electrocardiogram (r = 0.81, p <0.0001). Abnormalities in RV deformation were more marked in patients with transannular patches versus infundibular patches. In the septum there was a homogenous reduction in SR and ϵ in the basal, mid-, and apical segments. These averaged –1.4 ± 0.3 second−1 for SR and –19 ± 4% for ϵ, respectively (p <0.01 vs normals). Longitudinal SR and ϵ values of the 3 LV lateral wall segments (averaged SR = −1.6 ± 0.4 second−1, averaged ϵ = −20 ± 5%; p <0.05 vs normals), and radial SR and ϵ of the LV posterior wall (SR = 3.3 ± 0.9 second−1; ϵ = 51 ± 14%; p <0.05 vs normals) were significantly reduced. Thus, abnormalities in regional RV and LV systolic myocardial function in asymptomatic postoperative TOF patients were quantified by the deformation parameters SR and ϵ. RV deformation abnormalities are associated with electrical depolarization abnormalities.

ファロー四徴症根治手術後急性期および遠隔期における両心室機能の検討

ファロー四徴症根治手術後急性期および遠隔期における両心室機能の検討

Age-related changes in right and left ventricular function in tetralogy of Fallot.

Age-related changes in right (RV) and left (LV) ventricular myocardium in tetralogy of Fallot (TF) are analyzed with regard to pre- and postoperative ventricular function. In RV, preoperative function was better in patients under 4 years of age in terms of ejection fraction and compliance, but no significant change was seen in LV function. Postoperatively, patients who underwent corrective surgery at age less than 4 years showed no significant difference compared to those at operative age above 4 years in terms of RV and LV functions at rest. However, stress tests for RV by isoproterenol and LV using methoxamine revealed some masked ventricular dysfunction in both ventricles in the older groups. The relationships between these functional abnormalities and previously described histological changes of right and left ventricular myocardium in TF are discussed.

Factors affecting left ventricular function after correction of tetralogy of Fallot.

To investigate the possible causes of left ventricular dysfunction after total correction of tetralogy of Fallot, 84 patients, aged 1 1/2 to 16 years, were studied by left ventricular cineangiography both before and a mean of 4.6 months after operation. Left ventricular ejection fraction and mean velocity of circumferential fibre shortening were calculated; using multivariate analysis the results were correlated with age at operation, the degree of hypoxia and polycythaemia before operation, occurrence of hypoxic spells, and the duration of operative procedures (cardiopulmonary bypass and aortic cross clamping). The postoperative left ventricular ejection fraction was decreased slightly or moderately in 46% of patients. The variable most significantly associated with altered left ventricular function was a history of hypoxic spells. Age, the degree of chronic hypoxia, and polycythaemia did not correlate significantly with left ventricular function indices. Although no correlation was found between the duration of cardiopulmonary bypass and left ventricular ejection fraction, bypass times exceeding 120 minutes were associated with decreased ejection fractions; this was statistically significant and independent of the variable "hypoxic spells". Thus repeated episodes of acute hypoxia and long operative procedures appear to have a deleterious effect on left ventricular function in tetralogy of Fallot.

Lung function in tetralogy of Fallot after intracardiac repair

Earlier studies have shown significant restrictive lung volume patterns in virtually all patients after shunt palliation and/or subsequent intracardiac repair (ICR) of tetralogy of Fallot. We have studied lung volumes and capacities, maximum voluntary ventilation (MVV), and maximum mid-expiratory flow (MEF[25-75]) at least 1 year after ICR in 123 patients, 91 males and 32 females, which included 54 who underwent primary ICR. All were evaluated by stress testing and 61 were studied serially from two to eight times at 12 to 18 months intervals. In contrast to the previous studies, we found a lower incidence and lesser degrees of restrictive lung volume patterns. Lung volumes may be entirely normal particularly after primary ICR but also when ICR is preceded by shunt palliation. After reoperation for ICR normal lung volumes are uncommon. These is a high correlation between abnormal lung volumes and poor surgical results of ICR as manifested by residual cardiac disease, notably pulmonic valve insufficiency and increased heart size. In primary repair we found no correlation between the presence of abnormal lung volumes and the age at ICR (range 1.87 to 15.4 years). Abnormal lung volumes correlate with reduced exercise performance, but the latter is limited by cardiovascular rather than pulmonary factors. Serial studies show stable lung volume patterns with time, and we found no evidence that the increased level of physical activity usually present after ICR results in increases of lung volumes in excess of those predicted from somatic growth. We conclude that an excellent surgical repair of tetralogy is the best guarantee against a significant restrictive lung volume pattern after repair.

The effect of natural and surgically constructed aortopulmonary shunts on hemodynamic function in tetralogy of fallot: A. T. Look, Jr. and T. R. Bates, Jr. Ann Thorac Surg 20: 571–580 (November), 1975

The effect of natural and surgically constructed aortopulmonary shunts on hemodynamic function in tetralogy of fallot: A. T. Look, Jr. and T. R. Bates, Jr. Ann Thorac Surg 20: 571–580 (November), 1975

The Effect of Natural and Surgically Constructed Aortopulmonary Shunts on Hemodynamic Function in Tetralogy of Fallot

A hemodynamic model has been developed for the patient with tetralogy of Fallot. Equations representing the circulatory flow pattern and oxygen balance in this disease were incorporated into a computer program. With the computer model it is possible to simulate the effect of natural and surgically constructed aortopulmonary shunt flow on hemodynamic function in tetralogy of Fallot. Graphic representations of the computer output are presented which show how aortopulmonary shunt flow influences the physiology of exercise and hypoxic episodes. An explanation is advanced for the lack of correlation between resting arterial oxygen saturation and the incidence of hypoxic episodes. The model demonstrates the effect of surgical aortopulmonary shunts in eliminating hypoxic spells.