What Is the Importance of Electrocardiography in the Routine Screening of Patients with Repaired Tetralogy of Fallot?

Background: In patients following complete repair of the tetralogy of Fallot, the duration of the QRS complex is associated with the size and mechanical function of the right ventricle, which are contemporarily assessed by cardiac magnetic resonance (CMR). Methods: 38 patients aged 18.0–54.9 years (median age 24.9 years) who had undergone complete repair of the tetralogy of Fallot were examined using CMR and concomitant 24 h ambulatory electrocardiography monitoring. We used statistical analysis to investigate the correlations between electrocardiographic parameters (heart rate, HR; PQ interval, PQ; QRS duration, QRS; and corrected QT interval, QTc) and CMR results (right ventricular ejection fraction, RVEF; right ventricular end-diastolic volume index, RVEDVI; and right ventricular end-systolic volume index, RVESVI) for patients after early and late repair. Results: The ECG-based parameters were not correlated with time since repair. There were significant correlations between QRS duration and RVEF (r = −0.61), RVEDVI (r = 0.56), and RVESVI (r = 0.54) for early operated patients but not for late-operated patients. No other substantial correlations were reported. Conclusion: Despite its role in screening for arrhythmias, electrocardiography has a limited role as a predictor of morphology and function of the right ventricle in patients after repair of the tetralogy of Fallot.

870 Surgical Outcomes of Primary and Two-Stage Atrioventricular Septal Defect (AVSD) Repair: A Single Institution Experience

Objective To examine the surgical outcomes of primary and two-stage repair of complete atrioventricular septal defect(AVSD). Method This retrospective study included 74 patients who underwent operation for balanced complete AVSD between January 2015 and December 2018 in National Heart Centre Kuala Lumpur. Patient demographics, types of procedure, post-op complications and follow-up atrioventricular (AV) valve function were analysed. Results Twenty-one patients (median age: 3 months(2.28-4.32months)), weight: 3.10kg( 2.7-3.82kg)) had Pulmonary Artery Banding (PAB) prior to complete AVSD repair. The post-banding weight of patients rose from 3.1kg to 6.4kg prior to complete repair. The rate of ventilator dependence decreased from 19.8 to 4.8%. There was no worsening of post-banding left AV valve insufficiency (5%) before the complete repair. There was no statistically significant difference in the outcomes after complete AVSD repair in both groups (mortality p = 0.133, morbidities p = 0.471). There was a trend towards higher left AV valve insufficiency in the PAB group over time (at discharge, 10 vs 12%; at 3-months, 12 vs 6%; at 1-year, 14 vs 11%). Similarly, the PAB group also demonstrated a trend towards higher rates of major post- operative complications (33 vs 21%) and in-hospital mortality (9.5 vs 1.9%). Conclusions PAB remained as an effective palliative procedure for patients who are not suitable for primary AVSD repair at the time of presentation. However, it is associated with a higher incidence of left AV valve insufficiency at follow up.

Near Complete Repair After Myocardial Infarction in Adult Mice by Altering the Inflammatory Response With Intramyocardial Injection of α-Gal Nanoparticles

Background: Neonatal mice, but not older mice, can regenerate their hearts after myocardial-infarction (MI), a process mediated by pro-reparative macrophages. α-Gal nanoparticles applied to skin wounds in adult-mice bind the anti-Gal antibody, activate the complement cascade and generate complement chemotactic peptides that recruit pro-reparative macrophages which are further activated by these nanoparticles. The recruited macrophages decrease wound healing time by ~50%, restore the normal skin structure and prevent fibrosis and scar formation in mice.Objectives: The objective of this study is to determine if α-gal nanoparticles injected into the reperfused myocardium after MI in adult-mice can induce myocardial repair that restores normal structure, similar to that observed in skin injuries.Methods and Results: MI was induced by occluding the mid-portion of the left anterior descending (LAD) coronary artery for 30 min. Immediately following reperfusion, each mouse received two 10 μl injections of 100 μg α-gal nanoparticles in saline into the LAD territory (n = 20), or saline for controls (n = 10). Myocardial infarct size was measured by planimetry following Trichrome staining and macrophage recruitment by hematoxylin-eosin staining. Left ventricular (LV) function was measured by echocardiography. Control mice displayed peak macrophage infiltration at 4-days, whereas treated mice had a delayed peak macrophage infiltration at 7-days. At 28-days, control mice demonstrated large transmural infarcts with extensive scar formation and poor contractile function. In contrast, mice treated with α-gal nanoparticles demonstrated after 28-days a marked reduction in infarct size (~10-fold smaller), restoration of normal myocardium structure and contractile function.Conclusions: Intramyocardial injection of α-gal nanoparticles post-MI in anti-Gal producing adult-mice results in near complete repair of the infarcted territory, with restoration of normal LV structure and contractile function. The mechanism responsible for this benefit likely involves alteration of the usual inflammatory response post-MI, as previously observed with regeneration of injured hearts in adult zebrafish, salamanders and neonatal mice.

Association of Pulmonary Valve Morphology Differences With Outcomes in Tetralogy of Fallot Repair With Right Ventricular Outflow Tract Incision

Background: Current observational studies may not have large samples to investigate the relationship between pulmonary valve (PV) morphology differences and outcomes after complete repair for tetralogy of Fallot (TOF) by right ventricular outflow tract (RVOT) incision. This study aimed to assess the impact of PV morphology differences on outcomes after complete repair for TOF.Methods: This is a retrospective cohort study. Consecutive patients who underwent TOF repair with RVOT incision at Fuwai Hospital from January 2012 to December 2017 were included and compared according to PV morphology differences (unicuspid or bicuspid was abnormal morphology, while the tricuspid valve was normal morphology). The primary outcome was defined as a composite of death, or reintervention, or significant annular peak gradient (APG), or significant pulmonary regurgitation (PR), whichever occurred first. Multivariable Cox model analysis was used to assess the relationships between PV morphology differences and outcomes. Subgroup analysis and Propensity-score analysis were performed as sensitivity analyses to assess the robustness of our results.Results: The cohort included a total of 1,861 patients with primary diagnosis of TOF, with 1,688 undergoing CR-TOF with RVOT incision. The median age was 318 days [interquartile range (IQR): 223–534 days], a median weight of 8.9 kg (IQR: 7.6–10.5 kg) and 60.0% (1,011) were male. Complete follow-up data were available for 1,673 CR-TOF patients with a median follow-up duration of 49 months. Adjusted risks for the primary outcome and significant APG were lower for patients with normal PV morphology at follow up [adjusted hazard ratio (HR): 0.68; 95% CI: 0.46–0.98; adjusted HR: 0.22; 95% CI: 0.07–0.71, respectively]. The trend for the primary outcome during follow-up remained unchanged, even in subgroups and propensity score matching analyses.Conclusions: In this analysis of data from a large TOF cohort, patients with normal tricuspid PVs were associated with a decreased risk of the primary outcome and a lower risk of significant APG, as compared with patients with abnormal unicuspid or bicuspid PVs.

Beta-blocker use after complete repair of tetralogy of Fallot: an analysis of a national database

Introduction: In patients with right ventricular diastolic dysfunction after complete repair of tetralogy of Fallot, some employ the use of beta-blockade. The theoretical benefit of this therapy is felt to be one of the two: 1) reduction in heart rate with subsequent increase in diastolic filling time and stroke volume; 2) halting or reversal of right ventricular remodelling. This study aimed to characterise the use of beta-blockade in paediatric admissions with complete repair of tetralogy of Fallot and characterise the effects of beta-blockade on admission characteristics. Methods: Admissions from 2004 to 2015 in the Pediatric Health Information System database with complete repair of tetralogy of Fallot were identified. Characteristics between admissions with and without beta-blockade were compared by univariate analysis. Next, regression analyses were conducted to determine the independent association of beta-blockade on length of admission, billed charges, cardiac arrest, and inpatient mortality while controlling for demographic variables and comorbidities. Results: A total of 3594 admissions were included in the final analyses. Of these, 371 employed beta-blockade. Admissions with beta-blockade were more likely to have heart failure and tachyarrhythmias. These admissions also tended to be longer by univariate analysis. Regression analyses demonstrated that beta-blockade was independently associated with a 2.8-day increase in length of stay and no statistically significant change in billed charges, cardiac arrest, or inpatient mortality. Conclusions: Beta-blockade after complete repair of tetralogy of Fallot is associated with a longer length of stay but did not statistically significantly impact billed charges, cardiac arrest, or inpatient mortality.

Outcomes After Repair of Pulmonary Atresia With Ventricular Septal Defect and Major Aortopulmonary Collateral Arteries: A Tailored Approach in a Developing Setting

Objectives: Pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries (PA/VSD/MAPCAs) is complex and diverse that has led to a variety of treatment strategies. Experience has been largely obtained in the advanced countries. The clinical diversity is greater in China. We evaluated our surgical approaches and outcomes of these patients.Methods: We reviewed 127 patients undergoing varied surgeries in our center in 2010–2019.Results: Thirty patients underwent single-stage complete repair by unifocalizing MAPCAs and VSD closure (aged 3.9–131.4 months, median 22) with 3 (10%) early deaths. Ninety-seven underwent the first-stage rehabilitation strategy including systemic-to-pulmonary shunt in 29 (aged 0.5–144 month, median 8), and palliative RV-PA conduit in 68 (aged 2.2–209.6 months, median 14) with 5 (5.2%) early deaths. Eight-one patients (63.8%) eventually achieved complete repair with a median right/left ventricular (RV/LV) pressure ratio of 0.7 (ranged 0.4–1.0). Fourteen patients (11.0%) accepted palliation as final destination. Survival for the entire cohort was 89.5, 85.2, and 76.1% at 1, 5, and 10 years, respectively. Survival for those undergoing complete repair was 88.2 and 76.6% at 1 and 5 year, respectively. RV/LV pressure ratio ≥0.8 was risk factor for mortality (HR10.3, p = 0.003).Conclusions: Our cohort, the largest from China, had distinctive clinical features with substantially wider age range and higher RV/LV pressure ratio. Using the combined approaches tailored to individual patients, complete repair was achieved in 64% of patients. The early and intermediate outcomes are acceptable compared to many of the previous reports.