Risk factors for mortality in patients with hypoplastic left heart syndrome after the Norwood procedure.

OBJECTIVES: Several studies have reported mortality risk factors associated with hypoplastic left heart syndrome (HLHS). However, these data are ambiguous and mainly focused on the independent effects of these factors. We examined both the independent and the cumulative effects of preoperative risk factors for poor outcome in patients undergoing the Norwood procedure. Moreover, we studied the risk factors associated with prolonged initial hospital stays in these patients. METHODS: We performed a retrospective national 18-year observational study of preoperative risk factors for 1 year, as well as total follow-up mortality or need for transplant in patients with HLHS (N = 99) born in Finland between 1 January 2004 and 31 December 2021. RESULTS: Overall, one-year survival was 85.6%. In a multivariable analysis, having a major extracardiac anomaly and being small for gestational age were significant predictors of one-year mortality or the need for a transplant. Aortic atresia was a predictor of total follow-up mortality. An analysis of the cumulative effect indicated that the presence of 2 risk factors was associated with higher mortality. CONCLUSIONS: HLHS remains the defect with the highest procedural risks for mortality in paediatric cardiac surgery. From a prognostic point of view, recognition of independent preoperative risk factors as well as the cumulative effect of risk factors for mortality is essential.The results of this study were presented orally at the 55th Annual Meeting of the Association for European Paediatric and Congenital Cardiology, Geneva, Switzerland, 28 May 2022.

Multicenter cohort study on duration of antiarrhythmic medication for supraventricular tachycardia in infants.

Antiarrhythmic medication (AM) is commonly used to prevent supraventricular tachycardia (SVT) recurrence in infants. Our aim was to determine whether a shorter duration of AM is sufficient to prevent atrioventricular reentrant tachycardia (AVRT) recurrence and evaluate risk factors for recurrence of SVT after discontinued AM.This multicenter cohort study included all infants diagnosed with SVT in the five university hospitals in Finland between 2005 and 2017. Those diagnosed between 2005 and 2012 received AM for 12 months (group 1), and those diagnosed between 2013 and 2017 received AM for 6 months (group 2). A total of 278 infants presented with AVRT (group 1, n = 181; group 2, n = 97), and the median AM duration was 12.0 months (interquartile range [IQR] 11.4-13.4) and 7.0 months (IQR 6.0-10.2), respectively. Propranolol was the most frequently used first-line AM (92% and 95%). Recurrence-free survival rates were over 88% until 12 months after AM prophylaxis in both groups, without any statistically significant difference between them. Independent risk factors for recurrence of SVT after discontinuation of AM were need of combination AM (HR 2.2, 95% CI 1.14-4.20), Wolff-Parkinson-White (WPW) syndrome (HR 2.4, 95% CI 1.25-4.59), and age over 1 month at admission (HR 2.2, 95% CI 1.12-4.48).    Conclusion: Shortening AM duration in infants from 12 to 6 months does not seem to lead to more frequent SVT recurrence. The risk factors for recurrence of SVT were WPW syndrome, need of combination AM, and age over 1 month.

Rare Variants in Genes Associated With Cardiomyopathy Are Not Common in Hypoplastic Left Heart Syndrome Patients With Myocardial Dysfunction.

Myocardial dysfunction is a known risk factor for morbidity and mortality in hypoplastic left heart syndrome (HLHS). Variants in some transcription factor and contractility genes, which are known to cause cardiomyopathy, have previously been associated with impaired right ventricular function in some HLHS patients. The care of HLHS patients is resource demanding. Identifying genetic variants associated with myocardial dysfunction would be helpful in tailoring the follow-up and therapeutic strategies. We tested whether a commercial cardiomyopathy gene panel could serve as a diagnostic tool in a Finnish cohort of HLHS patients with impaired right ventricular function to identify potentially pathogenic variants associated with poor prognosis. None of the patients had pathogenic or likely pathogenic variants in the studied cardiomyopathy-associated genes. Thus, our approach of performing a cardiomyopathy gene panel to identify pathogenic variants as directly causal or as modifiers for worse outcomes in hypoplastic left heart syndrome is not useful in clinical practice at the moment.

Initial shunt type at the Norwood operation impacts myocardial function in hypoplastic left heart syndrome.

OBJECTIVES: We investigated the impact of initial shunt type, a Blalock-Taussig (BT) shunt versus a right ventricle to pulmonary artery conduit (RV-PA) on myocardial function at different stages of surgical palliation in patients with hypoplastic left heart syndrome (HLHS). METHODS: A population-based cohort of 63 Finnish children with HLHS (BT n = 23, RV-PA n = 40) born between 2003 and 2010 were studied retrospectively by echocardiography prior to Stages 1, 2 and 3 palliation and 0.5-3 years after Stage 3. For comparison of systolic myocardial function, we evaluated the RV fractional area change (FAC), strain, strain rate and mechanical synchrony from the apical 4-chamber view by velocity vector imaging. RESULTS: There were no intergroup differences in demographics during the study period. At baseline, no intergroup differences were detected in RV systolic myocardial function. Before Stage 2, RV FAC was higher ( P = 0.03) in the RV-PA conduit group. At Stage 3, an increase in all systolic myocardial functional parameters was observed in the BT shunt group. After Stage 3, the BT shunt group had better RV systolic function. In multiple regression analysis, the shunt type and the stage of palliation had an impact on myocardial function. CONCLUSIONS: Although patients with HLHS initially palliated with a BT shunt demonstrate lower RV FAC after Stage I, RV FAC improves after Stage 2 with better systolic performance after Stage 3 compared with those initially palliated with an RV-PA conduit.

Right ventricular systolic function in hypoplastic left heart syndrome: A comparison of manual and automated software to measure fractional area change.

BACKGROUND: Quantitative echocardiographic assessment of right ventricular function is important in children with hypoplastic left heart syndrome (HLHS). The aim of this study was to examine the repeatability of different echocardiographic techniques, both manual and automated, to measure fractional area change (FAC) in patients with HLHS and to correlate these measurements with magnetic resonance imaging (MRI)-derived ejection fraction (EF). METHODS: Fifty-one children with HLHS underwent transthoracic echocardiography and cardiac MRI under the same general anesthetic as part of routine inter-stage assessment. FAC was measured from the apical four-chamber view using three different techniques: velocity vector imaging (VVI) (Syngo USWP 3.0; Siemens Healthineers), QLAB (Q-lab R 10.0; Philips Healthcare), and manual endocardial contour tracing (Xcelera, Philips Healthcare). Intra- and inter-observer variability was calculated using intra-class correlation coefficient (ICC). FAC was correlated with MRI EF calculated using a single standard method. RESULTS: Fractional area change had a good correlation with MRI-derived EF with an R value for VVI, QLAB, and manual methods of .7, .6, and .4, respectively. Intra- and inter-observer variability for FAC was good for automated echocardiographic methods (ICC>.85) but worse for manual method particularly inter-observer variability of FAC and end-systolic area. Both automated techniques tended to produce higher FAC values compared with manual measurements (P<.001). CONCLUSION: Automation improves the repeatability of FAC in HLHS. There are some differences between automated software in terms of correlation with MRI-derived EF. Measurement bias and wide limits of agreement mean that the same echocardiographic technique should be used during the follow-up of individual patients.

Right ventricular systolic function in hypoplastic left heart syndrome: a comparison of velocity vector imaging and magnetic resonance imaging.

AIMS: Velocity vector imaging (VVI) is an echocardiographic technique based on speckle tracking, which has been validated for the left ventricle (LV). It has not been validated to assess the systemic right ventricle (RV) in patients with hypoplastic left heart syndrome (HLHS). The aim of this study was to evaluate whether VVI measurements reliably reflect RV systolic function in patients with HLHS when compared with RV ejection fraction (EF) calculated using magnetic resonance imaging (MRI). METHODS AND RESULTS: In this prospective study, 49 children with HLHS underwent transthoracic echocardiography and cardiac MRI under the same general anaesthetic as a part of routine assessment between the different stages of palliative surgery. Global RV fractional area change (FAC-VVI), strain (S), strain rate (SR), and peak systolic velocity (V) were analysed from the apical four-chamber view using the VVI technique. MRI-derived EF was calculated from a short-axis cine stack of images. Intra- and interobserver reproducibility was excellent for all VVI parameters (intraclass correlation coefficient >0.9). All VVI-derived parameters, except myocardial velocity, correlated with MRI-derived EF (FAC-VVI: R = 0.7, P < 0.001; S: R = -0.5, P < 0.001; SR: R = 0.5, P = 0.001, and V: R = 0.1, P = 0.4). CONCLUSIONS: All VVI-derived parameters, except V, correlate with MRI-derived EF, with FAC being the best predictor of it. Reproducibility of all VVI parameters is excellent. VVI provides a useful tool for the follow-up of RV function during the staged treatment protocol for HLHS.