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Background: Pulmonary valve replacement (PVR) is recommended for severe pulmonary regurgitation in repaired tetralogy of Fallot (rTOF)., Objective: The purpose of this study was to investigate the event rate and effectiveness of PVR., Methods: A retrospective study of tetralogy of Fallot patients who survived total repair from 1970 to 2020 was conducted., Results: We identified 1744 rTOF patients; 86.6% with classic rTOF, 11.5% with pulmonary atresia, 0.8% with endocardial cushion defect, and 1.1% with absent pulmonary valve. Annual risks of tachyarrhythmia/sudden cardiac arrest (SCA) increased to 0.295% and 1.338% in patients aged 10-30 and 30-60 years, respectively, without sex predominance. PVR (223 surgical and 39 percutaneous) event rate was 34.7% ± 2.1% by 30 years after repair (annual risk: 1.57% between 10 and 30 years after repair). The second PVR rate was 9.9% ± 4.1% by 20 years after the first PVR. Tachyarrhythmia/SCA risk was higher in PVR patients than in No PVR patients and was reduced in PVR patients without tachyarrhythmia/SCA before PVR. However, survival in patients with ventricular tachyarrhythmia/SCA still was better after PVR. At PVR, 13% of patients had tachyarrhythmia/SCA, which was the major predictor of events after PVR. Before PVR, although the ventricular tachyarrhythmia/SCA risks included QRS duration >160 ms and New York Heart Association functional class III or IV, supraventricular tachyarrhythmia was associated with PVR age ≥28 years and N-terminal pro-brain natriuretic peptide >450 pg/mL., Conclusion: Tachyarrhythmia/SCA occurrence and the need for PVR increased with age during young adulthood. PVR reduced subsequent arrhythmias only in those patients without arrhythmias before PVR., (Copyright © 2022 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Ventricular tachycardia (VT), which is related to haemodynamic and electrophysiological alterations, is an important complication in repaired tetralogy of Fallot (rTOF) patients. We defined the role of implantable cardioverter defibrillator (ICD) therapy after pulmonary valve replacement (PVR) and the implications of coexisting long QT gene mutations/polymorphisms., Methods: From 2003 to 2016, rTOF patients with VT who received ICD implantation were enrolled. rTOF patients without VT served as a control group. We performed long QT gene mutation analysis through the direct sequencing method., Results: In total, 12 (male/female, 8/4) patients with VT received ICD implantation. The mean age at TOF repair and ICD implantation was 4.4±4.5years and 27.1±11.5years, respectively. All but one patient received PVR for severe pulmonary regurgitation or repair for a residual ventricular septal defect. After 5.4±4.0years of follow-up, six patients (50%) had at least one episode of appropriate shock: two had received PVR with intraoperative arrhythmia ablation and two had received PVR only. Compared with 121 patients without VT, the ICD patients had a higher frequency of long QT gene mutation/polymorphisms (10/12 vs. 54/121, p=0.014), especially in the hERG and SCN5A genes. The mechanism of VT in rTOF was discussed thoroughly., Conclusion: In rTOF patients who received ICD as secondary prevention, the appropriate shock rate remained high despite PVR and intraoperative arrhythmia ablation. Coexisting long QT gene mutations/polymorphisms may be associated with ventricular arrhythmia., (Copyright © 2017. Published by Elsevier B.V.)

Parameters from cardiopulmonary exercise test (CPET) are useful prognostic factors for patients with repaired tetralogy of fallot (TOF). Its application in exercise prescription remains unclear. This study sought to define its role. We made current exercise recommendations in repaired TOF patients according to European Society of Cardiology (ESC) guideline, which were based on ventricular function, pressure/volume load, pulmonary artery pressure, hypoxemia and arrhythmic burden both at rest and during exercise. CPET parameters (peak oxygen consumption, oxygen uptake efficiency plateau, and E/CO 2 slope), along with cardiothoracic ratio, ventricular arrhythmia, QRS duration and NYHA functional status, were used to calculate "score to exercise". 112 repaired TOF adolescent and adult aged 32.6 ± 10.8 (14.05- to 56.99-year-old, median 30.1) years received exercise recommendations by ESC guideline, which suggested high, moderate and low intensity sports for 45 (40.2 %), 45 (40.2 %), and 22 (19.6 %) patients, respectively. The optimal cut-off values were 67 and 77 % for peak VO 2 , 86 and 100 % for OUEP, 22 and 28 for E/CO 2 slope to correlate to the exercise intensity recommendation. But, individual CPET parameter had low consistency (41-46 %) in making decisions of exercise intensity compared to ESC recommendations. Using the "score to exercise", the consistency rate could be increased to 74.1 %. With "score to exercise" recommended exercise intensity, follow-up result revealed no adverse event related to sports. Individual CPET parameter did not correlate well to the exercise recommendation from ESC. We proposed a scoring system, "score to exercise", which incorporates three CPET parameters with cardiothoracic ratio, ventricular arrhythmia, QRS duration and NYHA functional status. Score to exercise is easy to be assessed and provides useful information for exercise recommendation in patients with repaired TOF.

Background: Right ventricular (RV) outflow tract obstruction (RVOTO) might protect the RV from adverse remodeling caused by significant pulmonary regurgitation (PR) in patients with repaired tetralogy of Fallot (rTOF), but the underlying mechanisms and influences on exercise tolerance remain unclear. This study sought to investigate the impacts from mild RVOTO on ventricular remodeling and exercise capacity in rTOF., Methods: Eighty-five rTOF patients with a PR fraction ≥20% were assessed with cardiac magnetic resonance, cardiopulmonary exercise test, and echocardiography. Patients with a peak RVOT pressure gradient 20-50 mmHg were considered to have mild RVOTO (n = 29), while those with a gradient <20 mmHg had isolated PR (n = 56)., Results: Comparing to patients with isolated PR, patients with combined PR and mild RVOTO had smaller RV and RVOT dimension, better RV and left ventricular (LV) ejection fraction (EF), and superior exercise capacity. PR severity and RV mass/volume ratio were similar between these 2 groups. LVEF coupled with RVEF only in patients with isolated PR. In multivariate analysis, smaller RVOT dimension was independently related to smaller RV dimension (P < .001) and higher RVEF (P = .005). Furthermore, mild RVOTO was independently associated with higher peak oxygen consumption (P = .014) and oxygen uptake efficiency slope (P = .005)., Conclusions: Patients with combined PR and mild RVOTO had better RV remodeling and exercise capacity compared to those with isolated PR. Our findings confirm the benefits from mild residual RVOTO support a policy of conservative RVOTO relief at repair., (Copyright © 2014 Mosby, Inc. All rights reserved.)

Background: Right ventricular (RV) fibrosis is common in patients with repaired tetralogy of Fallot (rTOF). Although accumulating evidence indicates the role of circulating biomarkers of collagen metabolism in left ventricular fibrosis, rTOF data are lacking. This study examined the expression profile and clinical relevance of circulating biomarkers of collagen type I metabolism in rTOF patients., Methods: Serum biomarkers of collagen type I synthesis (carboxy-terminal propeptide of procollagen type I, PICP), degradation (carboxy-terminal telopeptide of collagen type I, CITP), and enzymes regulating collagen degradation (matrix metalloproteinases, and type I tissue inhibitor, TIMP-1) were measured in 70 rTOF and 91 control adults. All patients had complete clinical data and received cardiovascular magnetic resonance scans with late gadolinium enhancement (LGE)., Results: Compared to the controls, rTOF patients had higher PICP levels (p<0.001), PICP:CITP ratios (p<0.001), and TIMP-1 concentrations (p<0.001). Increasing PICP levels correlated with higher RV LGE scores (r=0.427, p<0.001), lower VO2max (r=-0.428, p=0.002), and larger RV volumes. Furthermore, stepwise multivariate linear regression analysis identified RV end-diastolic volume index >150mL/m(2) (β=40.52, p=0.016), RV LGE score (β=3.94, p=0.008), and age (β=-1.77, p=0.011) as independent correlates of circulating PICP levels., Conclusions: Patients with rTOF exhibited a profibrotic state with excessive collagen type I synthesis and dysregulated degradation. Elevated circulating PICP levels might reflect RV fibrosis, and link to adverse markers of clinical outcome., (Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.)

Background: Microvolt T wave alternans (MTWA) is an indicator of repolarization heterogeneity and a predictor of ventricular arrhythmia in adults with ischemic or dilated cardiomyopathy. Its implication in patients with repaired tetralogy of Fallot (TOF) is still unclear. This study sought to define the changes and the clinical implication of MTWA in these patients., Methods: Treadmill examination with modified moving average beat analysis (MMA) for MTWA was performed in 101 repaired TOF patients (60.4% male). Data from 103 age- and sex-matched subjects with normal hearts served as controls., Results: The age at latest follow-up was 20.0 ± 10.6 years. Total repair (60.4% received a transannular right ventricular outflow patch) was performed at a mean age of 4.8(± 5.8) years. After excluding 11 patients with indeterminate data, the MTWA data in 90 TOF patients revealed higher values than those in the control (25.1 ± 14.0 vs. 17.6 ± 9.2 μV, p<0.001). The values were best correlated to the presence of severe pulmonary regurgitation (p=0.006). Ten (9.9%) patients experienced late ventricular arrhythmic events. They tended to have higher MTWA values than those without (34.0 ± 16.5 vs. 24.2 ± 13.5 and p=0.053). Although the MTWA per se would not predict the late arrhythmia events better than QRS duration alone, the positive and negative predictive values increased slightly after adding the MTWA to QRS duration., Conclusions: MTWA, as measured by MMA, increased in repaired TOF patients particularly in those with severe pulmonary regurgitation and late arrhythmia events. To predict late ventricular arrhythmia, MTWA however was not superior to QRS duration alone., (Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.)

Coexisting long QT gene mutations/polymorphisms in Tetralogy of Fallot (TOF) patients may aggravate the repolarization abnormality from cardiac repair. We investigated the impact of these genes on the risk of life-threatening events. Genetic variants of the three common long QT genes were identified from patients with repaired TOF. Life-threatening events were defined as sudden cardiac death and hemodynamic unstable ventricular arrhythmia. Biophysical characterization of the alleles of the genetic variants was performed using a whole-cell voltage clamp with expression in Xenopus oocytes. A total of 84 patients (56.0 % male with 1,215 patients-year follow-up) were enrolled. Six rare variants and six non-synonymous single nucleotide polymorphisms (SNPs) were found in 40 (47.6 %) patients. Life-threatening events occurred in five patients; four received implantable cardioverter defibrillator and one died of sudden cardiac death. Life-threatening events occurred more often in those with genetic variants than those without (5/40 vs. 0/44, P = 0.021); particularly, the hERG or SCN5A gene mutations/polymorphisms (2/5 vs. 3/79, P = 0.027 and 5/27 vs. 0/57, P = 0.003, respectively). Among the five patients with life-threatening events, three had compound variants (hERG p.M645R/SCN5A p.R1193Q, hERG p.K897T/SCN5A p.H558R, and KVLQT1 p.G645S/SCN5A p.P1090L), that also increased the risk of events. Their QTc and JTc were all prolonged. Functional study of the novel variant (hERG gene p.M645R) from patients with life-threatening events revealed a dominant negative effect. In conclusion, in repaired TOF patients, coexisting long QT mutations/polymorphisms might have additive effects on the repolarization abnormality from surgery and thereby increase the risks of life-threatening events.

Unlabelled: Our aim was to evaluate the feasibility of using computed tomography (CT) to define the pulmonary artery anatomy in patients with tetralogy of Fallot and pulmonary atresia (TOF-PA). We retrospectively reviewed 110 patients with TOF-PA between 1995 and 2008. Those who received cardiac catheterization and surgery within 3 months of their CT examinations were enrolled. Based on Dr. Somerville's classification, the pulmonary arterial pattern was determined, including identifiable pulmonary trunk (type I), the presence of both left and right pulmonary arteries without trunk (II), only left or right pulmonary artery present (III), and absent intrapericardial pulmonary arteries (IV). The accuracy of both imaging modalities was evaluated with operation findings as the golden standard. The effective radiation doses and adverse events were also recorded. In the 64 eligible patients (median age, 23 months), CT and catheterization demonstrated accurate pulmonary arterial morphology in 60 (60/64) and 53 (53/64) TOF-PA patients, respectively. Thirty-two of 35 type I patients were correctly identified by CT, whereas 26 were correctly identified by catheterization (p = 0.03). Of the 20 type II TOF-PA patients, 19 were diagnosed by CT, whereas 18 were diagnosed by catheterization. CT and catheterization both successfully defined six type III and three type IV patients. The median calculated radiation doses caused by CT and catheterization were 4.5 and 5.6 mSv, respectively (p > 0.05)., Conclusions: For patients with TOF-PA, CT could accurately delineate pulmonary arterial morphology with the same level of accuracy as cardiac catheterization. Therefore, CT can be considered a reasonable diagnostic alternative for such patients.

Surgical repair of tetralogy of Fallot (TOF) in countries with sound medical care systems is seldom delayed until adolescence. This study investigated the clinical profile and the surgical outcomes in such a population from Taiwan. Between 1970 and 2009, 179 TOF patients (56% male) received total repair at 19.2 ± 8.3 (10-49) years of age. We reviewed the medical records and interviewed the patients concerning their current status. The survival was ascertained in all by a link to our national health database. Major morbidities before cardiac repair included atrial arrhythmia (1.1%), ventricular arrhythmia (3.9%), infective endocarditis (6.7%), brain abscess (4.6%) and pulmonary tuberculosis (3.3%). Ventricular arrhythmia and pulmonary tuberculosis occurred mainly after 20 years of age. Thirty patients (16.8%) received a palliative shunt. The preoperative QRS duration increment was 0.6 ms/year. Early mortality occurred in 4 (2.2%) and was related to previous shunt surgery (OR = 16.5, p < 0.05) and coronary artery crossing RVOT (OR 17.6, p < 0.05). After repair, the functional class improved in all patients. The median age at latest follow-up was 31.8 (32.8 ± 12.3) years. The survival was 92.7 and 89.3% at 20 and 30 years after operation, respectively. Late cardiovascular death could be predicted by the length of postoperative intensive care unit stay (OR = 1.3, p < 0.001). The freedom from ventricular arrhythmia 30 years after repair was 84.1% and was associated with a final QRS longer than 160 ms. Unrepaired TOF patients were at high risk of infective endocarditis, brain abscess, pulmonary tuberculosis and arrhythmias during their adolescence and adulthood. Cardiac repair in this age group was still safe and effective.

Background: Tetralogy of Fallot (TOF) is the most common cyanotic congenital heart disease in Taiwan. This study investigates the long-term survival and risks of TOF in an Asian cohort., Methods and Results: This study enrolled 819 consecutive patients with TOF (61.1% male), who received total correction between 1970 and 2002, as participants. Patient medical records were reviewed, and the survival status of those out of contact was confirmed by death records retrieved from the National Health database. The mean (±SD) patient age at cardiac repair was 6.5±7.6 years, and a prior shunt operation was performed in 119 (14.5%) of the patients. At cardiac repair, a transannular patch for right ventricle outlet reconstruction was required in 444 (54.2%) of the patients. After 13,808 patient-years of follow-up, the 30-year survival rate was 90.5%. The annual mortality rate increased from 0.123% in the initial 15 years after repair to 0.395% thereafter (P<0.05). The presence of major aortopulmonary collateral arteries, older operative age, and previous shunt operation are independent risks of late cardiac deaths. Secondary to cardiac mortality, unnatural deaths (accident and suicide) accounted for 27.6% of late deaths, significantly higher compared with that of the general population (odds ratio, 2.18; P=0.028)., Conclusions: In this Asian TOF cohort, except for a late decrease after 15 years, long-term survival after cardiac repair was satisfactory. Although cardiac death was the most common cause of late death, accidents or suicide may also be associated with late mortality, suggesting a potential role for psychosocial support.

Pulmonary regurgitation and prolonged QRS duration of right bundle branch (RBB) block are common in repaired tetralogy of Fallot (TOF) and increase the risk of sudden death. We sought to establish an animal model to reflect both abnormalities. Twenty-one canines: group I (n = 7) received a surgical right ventricular outflow tract (RVOT) transannular patch plus pulmonary valve destruction; group II (n = 5) received RBB ablation and sham operation; and group III (n = 9) received combined interventions. Serial electrophysiological data were obtained up to 1 y. Procedure mortality was 27.6%. At 1 y, although severe pulmonary regurgitation was documented in most dogs in groups I (71%) and III (100%), progressive RVOT dilatation was noted in group III. RBB block was present in all dogs in groups II and III. However, the increments of QRS duration, QTc, JTc, and QT dispersion progression between 1 mo and 1 y were all greatest in group III. Ventricular arrhythmia events were frequent in group III (median 3.3/mo) but uncommon in groups I and II (median 1/mo). We have created a novel animal model that adequately reflects both the hemodynamic and electrophysiological characteristics of repaired TOF patients and can be applied to examine the risk of ventricular arrhythmias.

Background/purpose: Pediatric cardiac computed tomography (CT) is a noninvasive imaging modality used to clearly demonstrate the anatomical detail of congenital heart diseases. We investigated the impact of cardiac CT on the utilization of cardiac catheterization among children with congenital heart disease.Methods: The study sample consisted of 2648 cardiac CT and 3814 cardiac catheterization from 1999 to 2009 for congenital heart diseases. Diagnoses were categorized into 11 disease groups. The numbers of examination, according to the different modalities, were compared using temporal trend analyses. The estimated effective radiation doses (mSv) of CT and catheterization were calculated and compared.Results: The number of CT scans and interventional catheterizations had a slight annual increase of 1.2% and 2.7%, respectively, whereas that of diagnostic catheterization decreased by 6.2% per year. Disease groups fell into two categories according to utilization trend differences between CT and diagnostic catheterization. The increased use of CT reduces the need for diagnostic catheterization in patients with atrioventricular connection disorder, coronary arterial disorder, great vessel disorder, septal disorder, tetralogy of Fallot, and ventriculoarterial connection disorder. Clinicians choose either catheterization or CT, or both examinations, depending on clinical conditions, in patients with semilunar valvular disorder, heterotaxy, myocardial disorder, pericardial disorder, and pulmonary vein disorder. The radiation dose of CT was lower than that of diagnostic cardiac catheterization in all age groups.Conclusion: The use of noninvasive CT in children with selected heart conditions might reduce the use of diagnostic cardiac catheterization. This may release time and facilities within the catheterization laboratory to meet the increasing demand for cardiac interventions. [ABSTRACT FROM AUTHOR]