Outcomes in Pediatric Dilated Cardiomyopathy

Non-Cardiac Cause of Death in Selected Group Children with Cardiac Pathology: A Retrospective Single Institute Study

Background: Pediatricians and pediatric surgeons often face children with cardiomegaly and dilatative or hypertrophic cardiomyopathies presenting with or without symptoms. Some of these patients have already been diagnosed and received medication, and some present with completely unrelated pathologies. Methods: We performed a 4-year retrospective study on the causes and mechanisms of death of children with cardiac pathology who died outside the cardiology clinic of our hospital by studying the hospital charts and necropsy reports. All children who were in this situation in our hospital were included. Results: Most children in our study group were infants (81.82%), most were boys (81.82%), and in most cases, the cause or mechanism of death was unrelated to their heart condition, whether it had already been diagnosed or not (one case probably died as a result of a malignant ventricular arrhythmia). Additionally, 27.27% of children died as a consequence of bronchopneumonia, the same percentage died as a consequence of an acquired non-pulmonary disease or after surgery, and 18.18% died as a consequence of congenital malformations. Conclusions: Cardiac disease needs to be thoroughly investigated using multiple tools for all children presenting with heart failure symptoms, those with heart murmurs, and children scheduled for surgery of any type. The intensive care specialist and surgeon need to be aware of any heart pathology before non-cardiac surgical interventions.

Development of Cardiac Events and Functional Recovery Prediction Models for Pediatric Dilated Cardiomyopathy

Background: Since both the risk of death and the probability of spontaneous functional recovery (FR) coexist in association with pediatric dilated cardiomyopathy (DCMP), management should be based on individualized outcome predictions. Methods: A single-center retrospective review of 105 pediatric patients (age at presentation ≤ 18 years) with DCMP, managed between 1994 and 2017, was performed. Logistic regression was conducted to identify variables associated with FR and cardiac events (CEs), i.e., death or heart transplantation (HTPL), within 2 years after initial presentation. Two outcome prediction models were formulated using these variables. Results: Twenty-six (24.8%) and 51 patients (48.6%) experienced FR and CE, respectively, within 2 years after initial presentation. Predictors of mortality without HTPL were earlier era at presentation (HR: 4.13; 95% CI: 1.88-9.06; p < 0.001) and significant TR (≥moderate; HR: 4.31; 95% CI: 1.26-14.77; p = 0.020) in multivariable Cox regression model. Predictors of FR were recent era (HR: 4.49; 95% CI: 1.40-14.44; p = 0.0012), younger age at initial presentation (HR: 0.98 per 1 month increase; 95% CI: 0.97-0.99, p < 0.001), post-myocarditis DCMP (HR: 4.29; 95% CI: 1.32-13.93; p = 0.015), and arrhythmia-mediated DCMP (HR: 26.88; 95% CI: 2.61-276.70; p = 0.006). Risk factors for CEs was idiopathic DCMP (HR: 2.95; 95% CI: 1.32-6.56, p = 0.008). The low-risk group who had higher probability of FR than CE in prediction model had a slightly higher overall survival rate (71.4 vs. 52.2% at 10 years after presentation; log-rank p = 0.09) and a significantly higher HTPL-free survival rate (67.5 vs. 24.9% at 10 years after presentation; log-rank p < 0.001) than the high-risk group. Conclusions: Prognostication and management strategies for pediatric DCMP may be enhanced by risk stratification using outcome prediction modeling.

Whole-Exome Sequencing Reveals Novel Genetic Variation for Dilated Cardiomyopathy in Pediatric Chinese Patients

Dilated cardiomyopathy (DCM) is characterized by left or bilateral ventricular dilation and systolic dysfunction without rational conditions, which can lead to progressive heart failure and sudden cardiac death. Most of the pathogenic genes have been reported in adult population by locus mapping in familial cases and animal model studies. However, it still remains challenging to decipher the role of genetics in the etiology of pediatric DCM. We applied whole-exome sequencing (WES) for 30 sporadic pediatric DCM subjects and 100 non-DCM local controls. We identified the pathogenic mutations using bioinformatics tools based on genomic strategies synergistically and confirmed mutations by Sanger sequencing. We identified compound heterozygous nonsense mutations in DSP (c.3799C > T, p.R1267X; c.4444G > T, p.E1482X). In sporadic cases, the two heterozygous mutations in XIRP2 were identified. Then we performed an exome-wide association study with 30 case and 100 control subjects. Interestingly, we could not identify TTN truncating variants in all cases. Collectively, we observed a significant risk signal between carriers of TTN deleterious missense variants and DCM risk (odds ratio 4.0, 95% confidence interval 1.1-22.2, p = 3.12 × 10^-2). Our observations expanded the spectrum of mutations and were valuable in the pre- and postnatal screening and genetic diagnosis for DCM.