Development of quality metrics for ambulatory pediatric cardiology: Transposition of the great arteries after arterial switch operation.

OBJECTIVE: To develop quality metrics (QMs) for the ambulatory care of patients with transposition of the great arteries following arterial switch operation (TGA/ASO). DESIGN: Under the auspices of the American College of Cardiology Adult Congenital and Pediatric Cardiology (ACPC) Steering committee, the TGA/ASO team generated candidate QMs related to TGA/ASO ambulatory care. Candidate QMs were submitted to the ACPC Steering Committee and were reviewed for validity and feasibility using individual expert panel member scoring according to the RAND-UCLA methodology. QMs were then made available for review by the entire ACC ACPC during an "open comment period." Final approval of each QM was provided by a vote of the ACC ACPC Council. PATIENTS: Patients with TGA who had undergone an ASO were included. Patients with complex transposition were excluded. RESULTS: Twelve candidate QMs were generated. Seven metrics passed the RAND-UCLA process. Four passed the "open comment period" and were ultimately approved by the Council. These included: (1) at least 1 echocardiogram performed during the first year of life reporting on the function, aortic dimension, degree of neoaortic valve insufficiency, the patency of the systemic and pulmonary outflows, the patency of the branch pulmonary arteries and coronary arteries, (2) neurodevelopmental (ND) assessment after ASO; (3) lipid profile by age 11 years; and (4) documentation of a transition of care plan to an adult congenital heart disease (CHD) provider by 18 years of age. CONCLUSIONS: Application of the RAND-UCLA methodology and linkage of this methodology to the ACPC approval process led to successful generation of 4 QMs relevant to the care of TGA/ASO pediatric patients in the ambulatory setting. These metrics have now been incorporated into the ACPC Quality Network providing guidance for the care of TGA/ASO patients across 30 CHD centers.

Outcomes in children with Noonan syndrome and hypertrophic cardiomyopathy: a study from the Pediatric Cardiomyopathy Registry.

BACKGROUND: Studies of cardiomyopathy in children with Noonan syndrome (NS) have been primarily small case series or cross-sectional studies with small or no comparison groups. METHODS: We used the Pediatric Cardiomyopathy Registry database to compare the survival experience of children with NS and hypertrophic cardiomyopathy (HCM) with children with idiopathic or familial HCM and to identify clinical and echocardiographic predictors of clinical outcomes. RESULTS: Longitudinal data in 74 children with NS and HCM and 792 children with idiopathic or familial isolated HCM were compared. Children with NS were diagnosed with HCM before 6 months old more often (51%) than children with HCM (28%) and were more likely to present with congestive heart failure (CHF) (24% vs 9%). The NS cohort had lower crude survival than the group with other HCM (P = .03), but survival did not differ after adjustment for CHF and age at diagnosis. Within the NS cohort (1-year survival 78%), a diagnosis of HCM before age 6 months with CHF resulted in 31% 1-year survival. Lower height-for-age z score (hazard ratio 0.26, P = .005) in place of CHF and lower left ventricular fractional shortening z score (hazard ratio 0.79, P = .04) also independently predicted mortality. CONCLUSIONS: Patients with NS with HCM have a worse risk profile at presentation compared with other children with HCM, resulting in significant early mortality (22% at 1 year). Decreased height-for-age and lower, although still supranormal, left ventricular fractional shortening z score are independent predictors of mortality in patients with NS with HCM. Such patients should have an aggressive therapeutic approach including potential listing for cardiac transplantation.

Characteristics and outcomes of cardiomyopathy in children with Duchenne or Becker muscular dystrophy: a comparative study from the Pediatric Cardiomyopathy Registry.

OBJECTIVE: The aim of this study was to determine in pediatric Duchenne (DMD) and Becker muscular dystrophy (BMD) or other dilated cardiomyopathies (ODCM) whether outcomes differ by diagnosis. BACKGROUND: Children with dilated cardiomyopathy are treated as a single undifferentiated group. METHODS: This cohort study of 128 children with DMD, 15 with BMD, and 312 with ODCM uses outcome measures of left ventricular (LV) size and function, death, heart transplant, and death or transplant. RESULTS: At cardiomyopathy diagnosis, the DMD and BMD groups had similar mean ages (14.4 and 14.6 years), prevalence of congestive heart failure (CHF) (30% and 33%), and LV fractional shortening (FS) Z-scores (median, -5.2 for DMD and -6.7 for BMD). The BMD group had more severe mitral regurgitation (P = .05) and a higher mean LV end-diastolic dimension Z-score than the DMD group (2.9 +/- 1.5 vs 1.2 +/- 1.9, P = .002). Duchenne muscular dystrophy group survival was lower than in BMD or ODCM groups (P = .06) at 5 years (57%, 100%, and 71%, respectively). In BMD, 25% received cardiac transplants within 0.4 years of cardiomyopathy diagnosis. The combined DMD and BMD group had less LV dilation and a closer-to-normal LV FS at cardiomyopathy diagnosis than the ODCM group. After 2 years, LV dilation increased, and LV FS did not change in the combined DMD and BMD group; for ODCM patients, LV dilation did not progress, and LV FS improved. CONCLUSIONS: Children with DMD and cardiomyopathy have a higher mortality. Becker muscular dystrophy has a high heart transplantation rate in the 5 years after diagnosis of cardiomyopathy. Serial echocardiography demonstrates a different disease course for DMD and BMD patients compared with ODCM patients.

Autonomic alterations in cocaine-exposed infants.

BACKGROUND: Heart rate variability (HRV) reflects autonomic control of the heart. After intrauterine cocaine exposure, asymptomatic newborn infants within 72 hours of life have decreased HRV. It is unknown whether these alterations are transient (acute effect) or persist in older infants and possibly reflect a teratogenic effect of cocaine. METHODS: This study prospectively evaluated HRV in 2- to 6-month-old infants who were exposed to cocaine in-utero (Group 1, n = 71). Their data were compared to normal controls (Group 3, n = 77) and to newborns exposed to drugs other than cocaine (Group 2, n = 89). Based on our previous study, heavy and light cocaine exposure was also defined a priori as the amount of cocaine used during the pregnancy that was more than or less than the 70th percentile, respectively. RESULTS: At the age of 2 to 6 months, infants with in-utero cocaine exposure had higher vagal tone and higher HRV (total power) than normal controls (no exposure to drugs). Most of this increase in vagal tone occurred in the light-cocaine-exposure group. HRV and vagal tone in the heavy-cocaine-exposure group were similar to the noncocaine-exposed group. CONCLUSIONS: At 2 to 6 months of age, asymptomatic infants exposed to cocaine in-utero have recovered from lower HRV seen within 72 hours of age. Infants exposed to light cocaine recovered by a rebound by increasing their vagal tone to above-normal levels. A similar response was blunted in heavily-cocaine-exposed infants. These alterations noted at follow up suggest a possible teratogenic effect of cocaine on the developing autonomic system.

Diastolic alterations in infants exposed to intrauterine cocaine: a follow-up study by color kinesis.

BACKGROUND: During the first 48 hours of life, newborn infants exposed to cocaine in utero have left ventricular diastolic segmental abnormalities. It is unknown whether these abnormalities are transient because of short-term effects or persist in older infants, possibly reflecting a teratogenic effect of cocaine. METHODS: This study prospectively evaluated global and segmental systolic and diastolic cardiac parameters by color kinesis. The patients were 2- to 6-month-old infants who were exposed to cocaine in utero (N = 56). Their data were compared with normal control patients with no intrauterine drug exposure (N = 60) and newborns exposed to drugs other than cocaine (N = 72). RESULTS: At the age of 2 to 6 months, there was no significant difference in the measured color kinesis parameters among the cocaine-exposed and the 2 control groups (infants prenatally exposed to other drugs and no drugs). Infants exposed to heavy cocaine prenatally, as compared with the noncocaine-exposed group, had a significant (P =.007) increase in septal fractional area change during left ventricular filling. CONCLUSIONS: At 2 to 6 months of age, infants have recovered from initial left ventricular diastolic segmental alterations seen in the first 48 hours of life except for the septal wall in the heavily cocaine-exposed group.

Heart rate variability by triangular index in infants exposed prenatally to cocaine.

BACKGROUND: In adults, heart rate variability triangular index (HRVi) is a highly reproducible measure of heart rate variability (HRV), which makes it more suitable for use in longitudinal studies. Although normative data have been published for newborns, studies in infants with pathological conditions are lacking. METHODS: From 1997 to 2000, within the first 4 days of life, we prospectively evaluated HRVi in cocaine-exposed asymptomatic newborns (N = 97) by Holter monitoring. Their data were compared with infants from two control groups (one with no in utero drug exposure, N = 102; the other with exposure to alcohol, nicotine, or marijuana but no cocaine, N = 111). RESULTS: In assessing concordance between and within operators for HRVi, the intraclass correlations were 0.983 (95% CI: 0.958, 0.994) and 0.997 (95% CI: 0.984, 0.999), respectively. Infants with in utero cocaine exposure had significantly (P < 0.0001) lower HRVi than those exposed to other drugs and to no drugs in utero. If abnormal HRVi is defined as < fifth percentile for the no drug exposed group (HRVi < 8), 10% of the cocaine-exposed newborns, in contrast to 2% in each of the control groups (P = 0.003) had abnormal values. CONCLUSION: HRVi is a reliable measure to study heart rate variability in newborns. Asymptomatic infants with in utero cocaine exposure have lower HRVi. Our study supports the clinical use of an abnormal HRVi as a value < 8 for newborn infants.

Diastolic filling abnormalities by color kinesis in newborns exposed to intrauterine cocaine.

Because cocaine crosses the placenta, we prospectively evaluated global and segmental systolic and diastolic cardiac function by color kinesis in clinically asymptomatic newborns who were exposed to cocaine in utero (group 1, n = 82). Their data were compared with normal controls (group 3, n = 87) and newborns exposed to drugs other than cocaine (group 2, n = 108). During left ventricular filling, newborns exposed to cocaine, compared with groups 2 and 3, had significantly (P <.05) higher global fractional area change (%) (76 +/- 10.3 vs 72 +/- 9.4 and 72 +/- 9.1, respectively), regional fractional area changes (%) for the anterior, septal, inferior, and lateral wall, and in the index of asynchrony (at 50% filling 13.2 +/- 5.8 vs 11.3 +/- 4.1 and 11.6 +/- 4.2, respectively). There were no significant differences in systolic function among the 3 groups. Prenatal cocaine exposure in asymptomatic infants leads to higher global and segmental fractional area changes and asynchrony during diastole. The significance and course of these alterations require further investigation.

Quantification of regional left ventricular wall motion in newborns by color kinesis.

BACKGROUND: Normal values for regional left ventricular wall motion, although documented in adults, have not been reported in healthy newborns. METHODS: This study prospectively evaluated global and segmental systolic and diastolic cardiac function by color kinesis in clinically asymptomatic healthy newborns. RESULTS: Eighty-eight asymptomatic infants who were less than 48 hours old were studied. Systolic and diastolic parameters of global and regional left ventricular function are reported as means +/- SD, medians, 5th and 95th percentiles to establish the normative values for newborns. The reported fractional area changes during systole and diastole are similar to the reported normal values for older subjects. Higher body surface area significantly correlated with an increased peak velocity during systole, and fractional area changes during filling of the lateral wall. CONCLUSIONS: Our report of left ventricular regional wall-motion characteristics of healthy newborns, as evaluated by color kinesis, may help in the objective evaluation and management of newborns suspected to have global or segmental ventricular dysfunction.

Heart rate variability in healthy newborn infants.

In adults and older children, heart rate variability (HRV) is frequently used to study autonomic function noninvasively. Normal values of HRV in newborn infants, however, are not widely available. This problem may be partially attributed to the lack of standardization of different methods. This study assessed HRV in normal newborn infants using 24-hour Holter monitoring. From 1997 to 2000, we prospectively evaluated frequency- (spectral analysis), geometric-, and time-domain indexes of HRV in normal term infants. Ninety-six asymptomatic infants who were <72 hours old were studied. Frequency-domain parameters (power in the high, low, very low, ultra low, and total frequency domains), a geometric parameter (HRV triangular index), and time-domain parameters (SDNN, SDANN, SDNNi, r-MSSD, s-NN50) are reported as means +/- SD, medians, and 5th and 95th percentiles to establish the normative values for newborns. A high degree of correlation (r > or = 0.85, p <0.0001) was noted among the 3 vagal tone dependent parameters, such as high-frequency power (frequency domain), r-MSSD, and s-NN50 (time domain). Our study supports the use of vagal dependent time-domain parameters like r-MSSD and sNN50 as surrogates for high-frequency power in newborns. Because the data are reported as means +/- SD, medians, and 5th and 95th percentiles, their use facilitates the study of parasympathetic and sympathetic activity in comparable populations.