Incomplete RV Remodeling After Transcatheter ASD Closure in Pediatric Age

Disease severity, arrhythmogenesis, and fibrosis are related to longer action potentials in tetralogy of Fallot

BACKGROUND

Arrhythmias may originate from surgically unaffected right ventricular (RV) regions in patients with tetralogy of Fallot (TOF). We aimed to investigate action potential (AP) remodelling and arrhythmia susceptibility in RV myocardium of patients with repaired and with unrepaired TOF, identify possible correlations with clinical phenotype and myocardial fibrosis, and compare findings with data from patients with atrial septal defect (ASD), a less severe congenital heart disease.

METHODS

Intracellular AP were recorded ex vivo in RV outflow tract samples from 22 TOF and three ASD patients. Arrhythmias were provoked by superfusion with solutions containing reduced potassium and barium chloride, or isoprenaline. Myocardial fibrosis was quantified histologically and associations between clinical phenotype, AP shape, tissue arrhythmia propensity, and fibrosis were examined.

RESULTS

Electrophysiological abnormalities (arrhythmias, AP duration [APD] alternans, impaired APD shortening at increased stimulation frequencies) were generally present in TOF tissue, even from infants, but rare or absent in ASD samples. More severely diseased and acyanotic patients, pronounced tissue susceptibility to arrhythmogenesis, and greater fibrosis extent were associated with longer APD. In contrast, APD was shorter in tissue from patients with pre-operative cyanosis. Increased fibrosis and repaired-TOF status were linked to tissue arrhythmia inducibility.

CONCLUSIONS

Functional and structural tissue remodelling may explain arrhythmic activity in TOF patients, even at a very young age. Surprisingly, clinical acyanosis appears to be associated with more severe arrhythmogenic remodelling. Further research into the clinical drivers of structural and electrical myocardial alterations, and the relation between them, is needed to identify predictive factors for patients at risk.

The immediate haemodynamic response and right and left cardiac remodelling after percutaneous transcatheter closure of secundum atrial septal defect in children: a longitudinal cohort study

OBJECTIVE

We aimed to assess the immediate haemodynamic response and the timing of cardiac remodelling in paediatric secundum atrial septal defect patients who underwent percutaneous transcatheter closure.

METHODS

In this longitudinal cohort study with 41 paediatric secundum ASD patients who underwent PTC with Amplatzer Occluder device were assessed for immediate post-interventional haemodynamic response measured by catheterisation and was evaluated for right and left cardiac remodelling during a follow-up period of 12 months by transthoracic echocardiography. SPSS 20.0 was used for statistical analyses of pre- and post-interventional invasive haemodynamic parameters of the patients, and pre- and post-interventional TTE data compared with the values of the control group consisted of 39 healthy children.

RESULTS

The mean diameter of ASD was 13.9 ± 4.7 mm. PTC intervention in all patients completed with 100% success and 0% complication rates. All invasive haemodynamic data, except the ratio of pulmonary resistance to systemic resistance, significantly reduced after PTC (p < 0.05). TTE and PW Doppler revealed that right and left cardiac remodelling started as soon as the post-interventional 24th hour and completed in the 12th month.

CONCLUSIONS

This study with a very high interventional success rate can be counted as the first example of research on the haemodynamic response and timing of cardiac remodelling after PTC of secundum ASD in children. We suggest that future multicentric studies with larger cohorts and a comprehensive methodology like ours with longer follow-up periods would better serve to further assess the cardiac remodelling in children after PTC of secundum ASD.

Left and right ventricular speckle tracking study before and after percutaneous atrial septal defect closure in children

Objectives

To analyze the acute and short-term deformation changes of both right (RV) and left (LV) ventricular wall before and after transcatheter closure of atrial septal defect (ASD) secundum in children.

Outcome measures

To determine the feasibility of tissue Doppler and myocardial deformation imaging for evaluating RV and LV functions in children undergoing transcatheter ASD closure.

Patients and methods

A prospective study was performed for 32 children with hemodynamic significant ASD secundum before and 6 months after percutaneous ASD closure in the Pediatric Cardiology Division of Specialized Pediatric Hospital, Cairo University. Speckle tracking echocardiography (STE) of LV and RV global analysis (longitudinal and circumferential strain) before and after ASD transcatheter closure was performed.

Results

The mean age of the patients was 6.01 ± 3.19 (range: 3–9) years with a female to male ratio of 1.3:1. There was an improvement in the RV and LV myocardial performance index (MPI) 6 months post-ASD closure (RVMPI = 0.46 ± 0.069 vs. 0.38 ± 0.05, p < 0.0001; LVMPI = 0.49 ± 0.12 vs. 0.38 ± 0.08, p < 0.0001, respectively). By 2D STE, there was a significant improvement in the RV global longitudinal strain (GLS) 6 months post-ASD closure (−20.17 ± 3.14% vs. −25.86 ± 5.02%, p < 0.0001). There was a significant increase in the LV end-diastolic volume (EDV) and LV end-systolic volume (ESV) using 4D STE after device closure (LVEDV = 32.96 ± 10.99 mL vs. 44.024 ± 14.9017 mL, p < 0.0001; LVESV = 15.16 ± 6.08 mL vs. 21.76 ± 8.34 mL, p < 0.0001, respectively). Additionally, there was a significant improvement in the LV GLS after device occlusion (−19.17 ± 3.67% vs. −22.36 ± 4.72%, p = 0.009) using 4D TomTec software. There was a significant decrease in the RVEDV (54.65 ± 10.05 mL vs. 15.73 ± 8.67 mL) and RV stroke volume (25.15 ± 6.36 vs. 20.06 ± 7.2) after device occlusion using 4D TomTec software.

Conclusion

By using 4D STE, the LV GLS was significantly improved; in contrast, by 2D STE, the RV volume overload decreased and the RV GLS was improved on short term after transcatheter ASD secundum closure in children.

Biventricular reverse remodeling and relationship with mitral valve prolapse after transcatheter closure of ASD secundum, a 3D echocardiographic study

Introduction: Mitral valve prolapse (MVP) is the most common anomaly of the mitral valve. Several studies have shown prevalence of MVP in atrial septal defect (ASD) especially secundum types (II). The aims of this study is to show the potential role of 3D echocardiography in improving the diagnosis of MVP and to depict the relationship between reverse remodeling of the right and left ventricles (RV, LV) and MVP after transcatheter closure of ASD II.

Methods: Sixty patients underwent transcatheter closure of ASD II and completed follow up by 2D and 3D echocardiography in Cairo University Children Hospital before the procedure and at 24 hours, 1 and 6 months after the procedure.

Results: 3D echocardiography was more accurate than 2D echocardiography in detecting MVP frequency in ASD II patients (75% vs. 50%). Maximum statistically significant remodeling was detected by 3D echocardiography 1 month after the procedure (RV: LV ratio by 3D echocardiography 1.9±0.03 24 hours after the procedure vs. 1.6±0.03 1 months after the procedure, P <0.01) while 2D echocardiography was delayed in detecting biventricular reverse remodeling. 3D derived RV: LV ratio was accurate in detecting MVP status with a sensitivity of 88%.

Conclusion: MVP in ASD II may be related to Biventricular remodeling; 3D echocardiography is accurate in the detection of reverse remodeling as well as MVP in ASD II patients before and after device closure.