Impaired cardiac adrenergic innervation assessed by MIBG imaging as a predictor of treatment response in childhood dilated cardiomyopathy

Symptoms of dysautonomia, sleep disturbance, and abnormal cognition in pediatric heart failure

Sleep disorders, autonomic dysfunction, and abnormal cognition are important comorbidities in adult patients with heart failure and are associated with disease progression, morbidity, and mortality. The clinical incidence of these conditions is unknown in children with heart failure. We sought to determine the incidence of symptoms that may be attributable to autonomic dysfunction among children with dilated cardiomyopathy and heart failure. We performed a retrospective chart review of patients with dilated cardiomyopathy seen at our institution between 1999 and 2005. We reviewed charts for symptoms of dysautonomia, sleep problems, or abnormal cognition. From the records of 204 pediatric patients, we identified 69 patients aged 7-18 years with severe dilated cardiomyopathy. Of these, 55 (80%) had symptoms attributable to dysautonomia, 20 (29%) had evidence of sleep disturbance, and 3 (4%) had abnormal cognition. Dysautonomia and sleep disturbances are prevalent in children with heart failure, congruent with studies of adult patients. Based on our data, it is not possible to draw conclusions about any cognitive deficits in this population. Because relatively few subjects' charts explored symptoms of sleep disturbance, we speculate that sleep symptoms may be underappreciated.

Idiopathic dilated cardiomyopathy in children; Natural history and predictors of prognosis

Dilated cardiomyopathy is the most common type of heart muscle disease in children with idiopathic etiology in the majority of cases. Idiopathic dilated cardiomyopathy (IDCM) is a severe illness which carries a high mortality rate in the pediatric population. In order to characterize IDCM evolution and identify prognostic predictors in our pediatric cardiology center in the western province of Saudi Arabia, 55 patients with IDCM were evaluated clinically and by echocardiography. They were followed for a minimum of one year and a maximum of four and a half years. Patients less than two years of age represented 69% of the cohort. Gender distribution revealed 65.5% female and 35.5% male. Outcomes were divided into four groups: 25 patients (45.5%) improved (Group I), 17 patients (31%) had a stationary course (Group II), 13 patients (23.6%) deteriorated (Group III), and eventually 11 patients (from Group III) died. Survival rate was 80% with a mean follow-up period of 36.2 ± 22.1 months. The older the age at presentation, the worse the prognosis, with P value= 0.029. In this study, we found a significant correlation of prognosis with end diastolic volume (EDV) (P=0.05) as well as stroke volume (SV) (P=0.04) on presentation. However, fractional shortening of ejection fraction on presentation could not be correlated statistically to the prognosis. Also results suggested that higher z-score of intraventricular septum & Left ventricular posterior wall dimensions in diastole significantly correlated to favorable outcomes and higher z-score of Left ventricular end diastolic dimension (LVEDD) was significantly related to unfavorable outcome. We concluded that further multi-center studies are necessary to verify predictors of outcome in IDCM patients. Identification of markers affecting early myocardial function is essential to achieving improvements in treatments and consequently outcomes in this pediatric population.

Outcome Predictors for Pediatric Dilated Cardiomyopathy: A Systematic Review

Dilated cardiomyopathy comprises the largest group of pediatric cardiomyopathy functional types and is the most common indication for heart transplant in children over 5 years old. Prognostic factors for this condition have long been sought by many researchers. In a systematic review of these factors, we found 32 relevant articles published since 1976. Four studies report finding no predictive factors. In the remaining 28 studies, several factors indicating better prognosis stand out across multiple articles: younger age at diagnosis, higher left-ventricular fractional shortening and ejection fraction, and the presence of myocarditis. Results for other factors conflict across studies: severe mitral regurgitation, arrhythmias, and a family history of cardiomyopathy. Elevated left-ventricular end diastolic pressure was statistically significant in two studies, but it may be of limited utility as a result of its invasiveness. Although most children have congestive heart failure at presentation, only two studies found it to be a significant predictor of mortality. The largest study of this factor qualified the increased risk to 1 year after presentation. Other significant predictors that have not been analyzed or reported by more than one study group, are right ventricular failure and impaired cardiac adrenergic innervation, as detected by radiolabeled meta-iodobenzylguanidine imaging. Although 1- and 5-year survival rates have steadily improved, as more children with DCM receive cardiac transplants, event-free survival rates (the absence of "heart death" resulting in death or transplant) are similar to those from decades ago. A unified risk algorithm may assist in clinical decision-making but requires more studies. Other studies are needed to assess the post-transplant survival experience.

Echocardiographic predictors of adverse clinical events in children with dilated cardiomyopathy: a prospective clinical study

OBJECTIVES

To compare tissue Doppler (TD) velocities between patients with dilated cardiomyopathy (DCM) and normal controls and to determine whether TD velocities, Tei index, right ventricular fractional area change, and left ventricular ejection fraction (LVEF) predict adverse clinical outcomes in children with DCM.

METHODS

Prospective evaluation of children with DCM.

RESULTS

54 children with DCM and 54 age and sex matched control group participants were studied. Mitral inflow velocities were similar for both groups except for decreased mitral deceleration time in patients with DCM. Systolic and diastolic TD velocities at the mitral annulus (septal and lateral sides) and tricuspid annulus were significantly reduced in children with DCM compared with controls (p < 0.001 for each). By multivariate analysis, after adjustment for Tei index and right ventricular fractional area change, decreased LVEF and tricuspid velocity during early diastole (Ea) were predictors of the primary end point (PEP), a composite end point consisting of need for hospitalisation or the outcome transplantation or death. Tricuspid Ea velocity < 8.5 cm/s had 87% specificity and 60% sensitivity for reaching the PEP. LVEF < 30% had 68% specificity and 74% sensitivity for the PEP. Combined LVEF < 30% and tricuspid Ea < 11.5 cm/s had 100% specificity and 44% sensitivity for the PEP.

CONCLUSIONS

Children with DCM have significantly lower TD velocities than normal controls. In such cases, lower LVEF (< 30%) is more sensitive but less specific than lower tricuspid Ea velocities (< 8.5 cm/s) in predicting which patients are at risk of hospitalisation, transplantation, or death.