Search

Background: Genetic defects in the RAS/mitogen-activated protein kinase pathway are an important cause of hypertrophic cardiomyopathy (RAS-HCM). Unlike primary HCM (P-HCM), the risk of sudden cardiac death (SCD) and long-term survival in RAS-HCM are poorly understood., Objectives: The study's objective was to compare transplant-free survival, incidence of SCD, and implantable cardioverter-defibrillator (ICD) use between RAS-HCM and P-HCM patients., Methods: In an international, 21-center cohort study, we analyzed phenotype-positive pediatric RAS-HCM (n = 188) and P-HCM (n = 567) patients. The between-group differences in cumulative incidence of all outcomes from first evaluation were compared using Gray's tests, and age-related hazard of all-cause mortality was determined., Results: RAS-HCM patients had a lower median age at diagnosis compared to P-HCM (0.9 years [IQR: 0.2-5.0 years] vs 9.8 years [IQR: 2.0-13.9 years], respectively) (P < 0.001). The 10-year cumulative incidence of SCD from first evaluation was not different between RAS-HCM and P-HCM (4.7% vs 4.2%, respectively; P = 0.59). The 10-year cumulative incidence of nonarrhythmic deaths or transplant was higher in RAS-HCM compared with P-HCM (11.0% vs 5.4%, respectively; P = 0.011). The 10-year cumulative incidence of ICD insertions, however, was 5-fold lower in RAS-HCM compared with P-HCM (6.9% vs 36.6%; P < 0.001). Nonarrhythmic deaths occurred primarily in infancy and SCD primarily in adolescence., Conclusions: RAS-HCM was associated with a higher incidence of nonarrhythmic death or transplant but similar incidence of SCD as P-HCM. However, ICDs were used less frequently in RAS-HCM compared to P-HCM. In addition to monitoring for heart failure and timely consideration of advanced heart failure therapies, better risk stratification is needed to guide ICD practices in RAS-HCM., Competing Interests: Funding Support and Author Disclosures The project was supported through funding from the Ted Rogers Centre for Heart Research, the Heart and Stroke Foundation/Robert M Freedom Chair, and the Canadian Institutes of Health Research to Dr Mital. Dr Lynch is supported by a Heart Failure Research Fellowship from Bristol Myers Squibb, Mitacs, and Myant. Dr Mital has served as a consultant for Bristol Myers Squibb and Tenaya Therapeutics; and has received unrestricted education funding from Bristol Myers Squibb. Dr Conway has served as a medical monitor for the PumpKIN trial; and has received unrestricted education funding from Abbott. Dr Rossano has served as a consultant for Merck, Bayer, Myokardia, and Cytokinetics. Dr Kantor has served as a consultant for Novartis and AstraZeneca. Dr Balaji has served as a consultant for Milestone Pharmaceuticals and Janssen Pharmaceuticals; and has received a research support grant from the Medtronic External Research Program. Dr Godown has served as a consultant for Daiichi-Sankyo. Dr Aziz has served on the Medical Advisory Board for Medtronic. Dr Jeewa has served as a medical monitor for the PumpKIN trial; and has served as a consultant for Abbott. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Studies of children with dilated cardiomyopathy (DCM) have suggested that improved survival has been primarily due to utilization of heart transplantation., Objectives: This study sought to determine transplant-free survival for these children over 20 years and identify the clinical characteristics at diagnosis that predicted death., Methods: Children <18 years of age with some type of DCM enrolled in the Pediatric Cardiomyopathy Registry were divided by year of diagnosis into an early cohort (1990 to 1999) and a late cohort (2000 to 2009). Competing risks and multivariable modeling were used to estimate the cumulative incidence of death, transplant, and echocardiographic normalization by cohort and to identify the factors associated with death., Results: Of 1,953 children, 1,199 were in the early cohort and 754 were in the late cohort. Most children in both cohorts had idiopathic DCM (64% vs. 63%, respectively). Median age (1.6 vs. 1.7 years), left ventricular end-diastolic z-scores (+4.2 vs. +4.2), and left ventricular fractional shortening (16% vs. 17%) at diagnosis were similar between cohorts. Although the rates of echocardiographic normalization (30% and 27%) and heart transplantation (24% and 24%) were similar, the death rate was higher in the early cohort than in the late cohort (18% vs. 9%; p = 0.04). Being in the early cohort (hazard ratio: 1.4; 95% confidence interval: 1.04 to 1.9; p = 0.03) independently predicted death., Conclusions: Children with DCM have improved survival in the more recent era. This appears to be associated with factors other than heart transplantation, which was equally prevalent in both eras. (Pediatric Cardiomyopathy Registry [PCMR]; NCT00005391)., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to determine the incidence and predictors of recovery of normal echocardiographic function among children with idiopathic dilated cardiomyopathy (DCM)., Background: Most children with idiopathic DCM have poor outcomes; however, some improve., Methods: We studied children <18 years of age from the Pediatric Cardiomyopathy Registry who had both depressed left ventricular (LV) function (fractional shortening or ejection fraction z-score <-2) and LV dilation (end-diastolic dimension [LVEDD] z-score >2) at diagnosis and who had at least 1 follow-up echocardiogram 30 days to 2 years from the initial echocardiogram. We estimated the cumulative incidence and predictors of normalization., Results: Among 868 children who met the inclusion criteria, 741 (85%) had both echocardiograms. At 2 years, 22% had recovered normal LV function and size; 51% had died or undergone heart transplantation (median, 3.2 months), and 27% had persistently abnormal echocardiograms. Younger age (hazard ratio [HR]: 0.92; 95% confidence interval [CI]: 0.88 to 0.97) and lower LVEDD z-score (HR: 0.78; 95% CI: 0.70 to 0.87) independently predicted normalization. Nine children (9%) with normal LV function and size within 2 years of diagnosis later underwent heart transplantation or died., Conclusions: Despite marked LV dilation and depressed function initially, children with idiopathic DCM can recover normal LV size and function, particularly those younger and with less LV dilation at diagnosis. Investigations related to predictors of recovery, such as genetic associations, serum markers, and the impact of medical therapy or ventricular unloading with assist devices are important next steps. Longer follow-up after normalization is warranted as cardiac failure can recur. (Pediatric Cardiomyopathy Registry; NCT00005391)., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: The purpose of this study was to establish the incidence of and risk factors for sudden cardiac death (SCD) in pediatric dilated cardiomyopathy (DCM)., Background: The incidence of SCD in children with DCM is unknown. The ability to predict patients at high risk of SCD will help to define who may benefit most from implantable cardioverter-defibrillators., Methods: The cohort was 1,803 children in the PCMR (Pediatric Cardiomyopathy Registry) with a diagnosis of DCM from 1990 to 2009. Cumulative incidence competing-risks event rates were estimated. We achieved risk stratification using Classification and Regression Tree methodology., Results: The 5-year incidence rates were 29% for heart transplantation, 12.1% non-SCD, 4.0% death from unknown cause, and 2.4% for SCD. Of 280 deaths, 35 were SCD, and the cause was unknown for 56. The 5-year incidence rate for SCD incorporating a subset of the unknown deaths is 3%. Patients receiving antiarrhythmic medication were at higher risk of SCD (hazard ratio: 3.0, 95% confidence interval: 1.1 to 8.3, p = 0.025). A risk stratification model based on most recent echocardiographic values had 86% sensitivity and 57% specificity. Thirty of 35 SCDs occurred in patients who met all these criteria: left ventricular (LV) end-systolic dimension z-score >2.6, age at diagnosis younger than 14.3 years, and the LV posterior wall thickness to end-diastolic dimension ratio <0.14. Sex, ethnicity, cause of DCM, and family history were not associated with SCD., Conclusions: The 5-year incidence rate of SCD in children with DCM is 3%. A risk stratification rule (86% sensitivity) included age at diagnosis younger than 14.3 years, LV dilation, and LV posterior wall thinning. Patients who consistently meet these criteria should be considered for implantable cardioverter-defibrillator placement., (Copyright © 2012 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to evaluate the outcome and prevalence of viral endomyocardial infection after cardiac transplantation., Background: Viral myocardial infection causes heart failure, but its role after cardiac transplantation is unclear. We hypothesized that viral infection of the cardiac allograft reduces graft survival., Methods: Between June 1999 and November 2004, 94 pediatric cardiac transplant patients were screened for the presence of viral genome in serial endomyocardial biopsies (EMBs) using polymerase chain reaction (PCR) assays. Graft loss, advanced transplant coronary artery disease (TCAD), and acute rejection (AR) were compared in the PCR-positive (n = 37) and PCR-negative (n = 57) groups, using time-dependent Kaplan-Meier and Cox regression analyses. From November 2002 to November 2004, intravenous immunoglobulin therapy (IVIG) was administered to patients with PCR-positive EMBs. The outcomes of the IVIG-treated, PCR-positive patients (n = 20) were compared with IVIG-untreated, PCR-positive patients (n = 17)., Results: Viral genomes were detected in EMBs from 37 (39%) patients; parvovirus B19, adenovirus, and Epstein-Barr virus (EBV) were the most common. The PCR-positive group (n = 37, 25% graft loss at 2.4 years) had decreased graft survival (p < 0.001) compared with the PCR-negative group (n = 57, 25% graft loss at 8.7 years) and developed advanced TCAD prematurely (p = 0.001). The number of AR episodes was similar in both groups. On multivariate analysis, presence of viral genome was an independent risk factor for graft loss (relative risk: 4.2, p = 0.015). The time to advanced TCAD after becoming PCR-positive was longer in the IVIG-treated patients (p = 0.03) with a trend toward improved graft survival (p = 0.06)., Conclusions: Viral endomyocardial infection is an independent predictor of graft loss in pediatric cardiac transplant recipients. This effect appears to be mediated through premature development of advanced TCAD. IVIG therapy in this subgroup may improve survival and merits further investigation., (Copyright (c) 2010 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study was designed to review outcomes of pediatric isolated hypertrophic cardiomyopathy (HCM) managed uniformly at a single institution and assess whether reported adult risk factors for sudden death are predictive in pediatric HCM., Background: Cardiac death in HCM occurs suddenly (SCD) or may be nonsudden (non-SCD). Little data exists on non-SCD in children. Risk factors for SCD in adult HCM are characterized and consensus management strategies detailed. Their application to children is uncertain and treatment strategies vary., Methods: A retrospective cohort study of children with HCM was performed. Primary end points were cardiac death and transplantation. Frequency and outcomes of known adult risk factors were assessed. Outcomes analysis was performed using Kaplan-Meier curves and Cox regression analysis., Results: Ninety-six patients were included. The average age at diagnosis was 10.6 +/- 5.4 years, and mean follow-up was 6.4 +/- 5.2 years. Primary end points occurred in 11 patients over the 20-year follow-up (11%), 4 underwent cardiac transplant and 7 died (3 suddenly). Extreme left ventricular hypertrophy (z-score: >6) and an abnormal blood pressure response to exercise were predictive of non-SCD (p < 0.02 and p < 0.03, respectively). Kaplan-Meier survival analysis predicts an 82% survival over a 20-year period., Conclusions: In children with isolated HCM managed primarily with exercise restriction and medication, cardiac death occurred infrequently. Non-SCD or transplant was at least as common as SCD. Extreme left ventricular hypertrophy and blunted blood pressure response to exercise were associated with an increased risk of non-SCD.