Reexamining the emperor's new clothes: ambiguities in current cardiac screening recommendations for youth with attention deficit hyperactivity disorder

Ventricular arrhythmias in children with attention deficit disorder--a symptom of autonomic imbalance?

OBJECTIVES

Potential side effects of stimulants for attention deficit disorder are in the focus of scientific discussions, intensified by the higher number of prescriptions. Children with known arrhythmias or other severe cardiac problems should not receive stimulants because of their sympathomimetic effects.

METHODS

This is a retrospective analysis of 24-hour Holter electrocardiograms from 100 consecutive children with attention deficit disorder from January, 2006 to April, 2012.

RESULTS

In all, nine children had significant ventricular arrhythmia (mean age 11.4 ± 3.1 years, 77% male, 77% received methylphenidate). All these children had ventricular parasystole - four of them with an accelerated idioventricular rhythm. A significant circadian rhythm of premature ventricular contractions in seven children and the effect of standing and exercise clearly indicate the influence of the autonomic nervous system. In these children, hourly analysis of circadian rhythm within a 24-hour period showed a highly significant correlation between premature ventricular contractions and the vagal tone indicated by the heart rate variability parameter RMSSD (r = -0.83; p < 0.001). Ventricular arrhythmia was unaffected in seven children who received methylphenidate before diagnosis and decreased during metoprolol treatment in two children.

CONCLUSION

By Holter electrocardiogram analysis, we observed a remarkably high incidence of ventricular parasystole and accelerated idioventricular rhythm in nine of 100 children with attention deficit disorder, which depends on autonomic imbalance and not on stimulant treatment.

Sudden unexplained cardiac arrest in apparently healthy children: a single-center experience

This study aimed to determine the causes of sudden cardiac arrest (SCA) in apparently healthy children at a single center in the era of primary prevention (screening questionnaire [SQ]) and secondary prevention (automated external defibrillator [AED] and the automated implantable cardioverter defibrillator [AICD]). Any child 0 to 18 years of age without prior known disease, except for attention deficit disorder, who underwent out-of-the hospital cardiopulmonary resuscitation was included in the study as a SCA subject. A retrospective chart review was used to evaluate the efficacy of the SQ, electrocardiogram (ECG), chest roentgenogram (CXR), and echocardiogram. The findings showed that for 44 of 6,656 children admitted to intensive care with SCA, an AED was used for 39%, an AICD was placed in 18%,and survival to hospital discharge was 50%. The etiology for SCA was identified in 57% of the cases, mostly in those older than 1 year, and the majority of these had a cardiac etiology (50%), whereas 7% had rupture of an arteriovenous malformation. Stimulant medication use was seen in 11% of the SCA subjects. In the best-case scenario of hypothesized primary prevention, a prior SQ, CXR, ECG, or echocardiogram may have detected respectively 18, 9, 23 and 16% of the at-risk cases, and 32% of the cases may have been detected with ECG and SQ together. Based on a historical control cohort, a positive ECG was significantly higher in the children with SCA (p = 0.014). An ECG together with a screening SQ may be more effective in identifying children potentially at risk for SCA than an SQ alone.

How to predict the impact of methylphenidate on cardiovascular risk in children with attention deficit disorder: methylphenidate improves autonomic dysfunction in children with ADHD

Background. Although stimulants have long been touted as treatments for attention deficit disorder with or without hyperactivity (ADHD), in recent years, increasing concerns have been raised about the cardiovascular safety of these medications. We aimed to prove if measurements of autonomic function with time domain analysis of heart rate variability (HRV) in 24-hour Holter ECG are useful to predict the risk of sudden cardiac death in ADHD children and adolescents. Methods. We analysed HRV obtained from children with the diagnosis of ADHD prior to (N = 12) or during medical therapy (N = 19) with methylphenidate (MPH), aged 10.8 ± 2.0 years (mean ± SD), who were referred to our outpatient Paediatric Cardiology Clinic to rule out heart defect. As a control group, we compared the HRV data of 19 age-matched healthy children without heart defect. Results. Average HRV parameters from 24-hour ECG in the ADHD children prior to MPH showed significant lower values compared to healthy children with respect to rMSSD (26 ± 4 ms versus 44 ± 10 ms, P ≤ 0.0001) and pNN50 (6.5 ± 2.7% versus 21.5 ± 9.0%, P ≤ 0.0001). These values improved in MPH-treated children with ADHD (RMSSD: 36 ± 8 ms; pNN50: 14.2 ± 6.9%). Conclusion. Children who suffer from ADHD show significant changes in HRV that predominantly reflects diminished vagal tone, a well-known risk factor of sudden cardiac death in adults. In our pilot study, MPH treatment improved HRV.

Cardiac screening prior to stimulant treatment of ADHD: a survey of US-based pediatricians

OBJECTIVES

To determine pediatricians' attitudes, barriers, and practices regarding cardiac screening before initiating treatment with stimulants for attention-deficit/hyperactivity disorder.

METHODS

A survey of 1600 randomly selected, practicing US pediatricians with American Academy of Pediatrics membership was conducted. Multivariate models were created for 3 screening practices: (1) performing an in-depth cardiac history and physical (H & P) examination, (2) discussing potential stimulant-related cardiac risks, and (3) ordering an electrocardiogram (ECG).

RESULTS

Of 817 respondents (51%), 525 (64%) met eligibility criteria. Regarding attitudes, pediatricians agreed that both the risk for sudden cardiac death (SCD) (24%) and legal liability (30%) were sufficiently high to warrant cardiac assessment; 75% agreed that physicians were responsible for informing families about SCD risk. When identifying cardiac disorders, few (18%) recognized performing an in-depth cardiac H & P as a barrier; in contrast, 71% recognized interpreting a pediatric ECG as a barrier. When asked about cardiac screening practices before initiating stimulant treatment for a recent patient, 93% completed a routine H & P, 48% completed an in-depth cardiac H & P, and 15% ordered an ECG. Almost half (46%) reported discussing stimulant-related cardiac risks. Multivariate modeling indicated that ≥1 of these screening practices were associated with physicians' attitudes about SCD risk, legal liability, their responsibility to inform about risk, their ability to perform an in-depth cardiac H & P, and family concerns about risk.

CONCLUSIONS

Variable pediatrician attitudes and cardiac screening practices reflect the limited evidence base and conflicting guidelines regarding cardiac screening. Barriers to identifying cardiac disorders influence practice.

Pharmacotherapy for child and adolescent attention-deficit hyperactivity disorder

Research in the past 2 decades showed that attention-deficit/hyperactivity disorder (ADHD) is a frequently occurring psychiatric disorder that causes considerable suffering to patients and their families. This article outlines current pharmacologic ADHD treatment options and focuses on their safety profile and efficacy. In addition, it addresses treatment selection, guidelines for monitoring treatment, and recent controversies in the field.

Cardiovascular safety of stimulant medications for pediatric attention-deficit hyperactivity disorder

Attention-deficit hyperactivity disorder (ADHD) is a common neurobehavioral disorder that is often treated with stimulants such as methylphenidate and mixed amphetamine salts. Despite their efficacy and long history of use, there is concern about their potential for adverse cardiovascular effects in children and adolescents. Data from placebo-controlled and open-label extension trials published after 2000 were reviewed, and cardiovascular adverse event data were compared. Both placebo-controlled and open-label extension trials have repeatedly shown stimulant-induced increases in mean blood pressure, heart rate, and QT interval in children, adolescents, and adults. Although these increases seem relatively minor, their existence raises questions regarding whether stimulants could influence the likelihood of sudden death or other serious cardiovascular consequences, especially in patients with underlying heart problems. Moreover, questions have been raised regarding the necessity of screening patients for occult or unrecognized heart problems that are felt to be adversely affected by stimulant use. Obtaining a baseline electrocardiogram for any patient starting stimulant treatment is reasonable if access to such screening is readily available and not too costly.

Cost-effectiveness of preparticipation screening for prevention of sudden cardiac death in young athletes

BACKGROUND

Inclusion of 12-lead electrocardiography (ECG) in preparticipation screening of young athletes is controversial because of concerns about cost-effectiveness.

OBJECTIVE

To evaluate the cost-effectiveness of ECG plus cardiovascular-focused history and physical examination compared with cardiovascular-focused history and physical examination alone for preparticipation screening.

DESIGN

Decision-analysis, cost-effectiveness model.

DATA SOURCES

Published epidemiologic and preparticipation screening data, vital statistics, and other publicly available data.

TARGET POPULATION

Competitive athletes in high school and college aged 14 to 22 years.

TIME HORIZON

Lifetime.

PERSPECTIVE

Societal.

INTERVENTION

Nonparticipation in competitive athletic activity and disease-specific treatment for identified athletes with heart disease.

OUTCOME MEASURE

Incremental health care cost per life-year gained.

RESULTS OF BASE-CASE ANALYSIS

Addition of ECG to preparticipation screening saves 2.06 life-years per 1000 athletes at an incremental total cost of $89 per athlete and yields a cost-effectiveness ratio of $42 900 per life-year saved (95% CI, $21 200 to $71 300 per life-year saved) compared with cardiovascular-focused history and physical examination alone. Compared with no screening, ECG plus cardiovascular-focused history and physical examination saves 2.6 life-years per 1000 athletes screened and costs $199 per athlete, yielding a cost-effectiveness ratio of $76 100 per life-year saved ($62 400 to $130 000).

RESULTS OF SENSITIVITY ANALYSIS

Results are sensitive to the relative risk reduction associated with nonparticipation and the cost of initial screening.

LIMITATIONS

Effectiveness data are derived from 1 major European study. Patterns of causes of sudden death may vary among countries.

CONCLUSION

Screening young athletes with 12-lead ECG plus cardiovascular-focused history and physical examination may be cost-effective.

PRIMARY FUNDING SOURCE

Stanford Cardiovascular Institute and the Breetwor Foundation.