Electrocardiographic effects of desipramine and 2-hydroxydesipramine in children, adolescents, and adults treated with desipramine

Psychotropic drug concentrations and clinical outcomes in children and adolescents: a systematic review

INTRODUCTION

The use of psychotropic drugs in children and adolescents is widespread but associated with suboptimal treatment effects. Therapeutic drug monitoring (TDM) can improve safety of psychotropic drugs in children and adolescents but is not routinely performed. A major reason is that the relationship between drug concentrations and effects is not well known.

AREAS COVERED

This systematic review evaluated studies assessing the relationship between psychotropic drug concentrations and clinical outcomes in children and adolescents, including antipsychotics, psychostimulants, alpha-agonists, antidepressants, and mood-stabilizers. PRISMA guidelines were used and a quality assessment of the retrieved studies was performed. Sixty-seven eligible studies involving 24 psychotropic drugs were identified from 9,298 records. The findings were generally heterogeneous and the majority of all retrieved studies were not of sufficient quality. For 11 psychotropic drugs, a relationship between drug concentrations and side-effects and/or effectiveness was evidenced in reasonably reported and executed studies, but these findings were barely replicated.

EXPERT OPINION

In order to better support routine TDM in child- and adolescent psychiatry, future work must improve in aspects of study design, execution and reporting to demonstrate drug concentration-effect relationships. The quality criteria proposed in this work can guide future TDM research. Systematic review protocol and registration PROSPERO CRD42018084159.

Are one or two dangerous? Tricyclic antidepressant exposure in toddlers

Tricyclic antidepressants (TCA), increasingly prescribed for multiple indications in children and adults, are responsible for many pediatric poisonings. Though the majority of TCA exposures in this age group remain asymptomatic, several reports in the English language literature reveal significant morbidity as well as fatalities in toddlers, primarily from imipramine and desipramine. These few cases indicate that doses of 10-20 mg/kg (one to two pills) have the potential for toxicity and fatalities. More recent studies have focused on the relative safety of small exposures suggesting that with doses less than 5 mg/kg the patient may be safely observed at home. Though further studies are necessary to determine the exact dosing that places the child at risk, the authors recommend a 6-h Emergency Department observation period for children who ingest more than 5 mg/kg of most TCAs, as clinical toxicity becomes evident within this time frame.

Excess fatality from desipramine and dosage recommendations

Higher case fatality rates (CFR) were previously reported from desipramine than for 3 other tricyclic antidepressants (TCAs): amitriptyline, nortriptyline, and imipramine. The database of the American Association of Poison Control Centers (AAPCC) Toxic Exposure Surveillance System (TESS) for the 20 years 1983-2002 was used to evaluate the CFR of desipramine and the other TCAs. The CFR of desipramine was 2.25-, 2.31-, and 2.62-fold the CFR for amitriptyline, nortriptyline, and imipramine, respectively (P < 0.001). Mechanisms of desipramine toxicity and its dosage recommendations are discussed. Desipramine and nortriptyline have higher distribution volumes and erythrocyte/plasma ratios than their parent compounds imipramine and amitriptyline. This implies lower therapeutic plasma levels and reduced doses for desipramine and nortriptyline compared with their parent compounds. Such adjustments have been done for nortriptyline, but not for desipramine. The authors suggest that the high CFR of desipramine might be reduced by lowering its dose, therapeutic plasma level, and maximal pill content.

Attention-deficit/hyperactivity disorder in children and adolescents: interventions for a complex costly clinical conundrum

Management of a child or adolescent with attention-deficit/hyperactivity disorder (ADHD) is reviewed, including psychological and pharmacologic approaches. Psychological treatment includes psychotherapy, cognitive-behavior therapy, support groups, parent training, educator/teacher training, biofeedback, meditation, and social skills training. Medications are reviewed that research has revealed can improve the core symptomatology of a child or adolescent with ADHD. These medications include stimulants, antidepressants, alpha-2 agonists, and a norepinephrine reuptake inhibitor. Management of ADHD should include a multi-modal approach, involving appropriate educational interventions, appropriate psychological management of the patient (child or adolescent), and judicious use of medications. Parents, school officials, and clinicians must work together to help all children and adolescents with ADHD achieve their maximum potential.

An open-label, dose-ranging study of atomoxetine in children with attention deficit hyperactivity disorder

OBJECTIVE

The goal of this study was to evaluate the tolerability and effectiveness of the experimental, noradrenergic specific reuptake inhibitor atomoxetine in the treatment of children with attention deficit hyperactivity disorder (ADHD).

METHODS

This was an open, prospective, dose-ranging study of atomoxetine monotherapy in the treatment of 30 children with ADHD between the ages of 7 and 14 years. Atomoxetine was started at 10-20 mg/day and titrated weekly up to 90 mg over 11 weeks, depending on response and adverse effects. Twenty-two children completed the full 11 weeks. We assessed efficacy with weekly clinician and parent ratings of ADHD and oppositional symptoms and monitored adverse effects, laboratory findings, and cardiovascular parameters.

RESULTS

Treatment with atomoxetine (mean final, total daily dose of 1.9 mg/kg/day) was very well tolerated without meaningful adverse effects. Atomoxetine significantly reduced core symptoms of ADHD (ADHD-Rating Scale-IV; 38.6% decrease vs. baseline, p < 0.001) with significant improvement (p < 0.05) in all but 1 of the 18 individual items in the ADHD-Rating Scale-IV. More than 75% of subjects who completed 10 weeks of treatment showed > 25% decrease in ADHD symptoms.

CONCLUSIONS

These findings extend to children the positive results previously reported in adults diagnosed with ADHD who were treated with atomoxetine. These results support additional controlled trials of atomoxetine in cases of pediatric ADHD.

Sudden death related to selected tricyclic antidepressants in children: epidemiology, mechanisms and clinical implications

The association between tricyclic antidepressant (TCA) use in children and increased risk of sudden death is unclear, but still possible. There are suitable alternatives to TCAs for all of the indications in which they have shown efficacy. A prudent practice model for the utilisation of TCAs has been developed. This includes initial utilisation of alternative agents, with TCAs as secondary or tertiary choices; informed consent from patient and family, including mention of the possible relationship of TCA with sudden death; vigilance of the emerging literature; and finally, systematic monitoring of patients, including electrocardiograms, drug serum concentrations and vital signs. This protocol needs to be validated with regard to utility and the degree of assistance it provides in the management of children treated with TCAs.

Serum levels and cardiovascular effects of tricyclic antidepressants and selective serotonin reuptake inhibitors in depressed patients

Tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs) are used to treat depression. Whereas cardiovascular effects have occasionally been reported during controlled studies with SSRIs, TCA treatment poses a well-known problem in this respect. To investigate the putative correlation between antidepressant dose or serum levels and adverse effects, the authors devised a naturalistic study to evaluate the tricyclic antidepressants' and SSRIs' effect on the cardiovascular system. The authors also compared antidepressant serum levels to adverse effects. Inpatients treated with TCAs or SSRIs were included; an electrocardiogram (ECG) and a Schellong test were carried out on the day patients entered the hospital and during steady-state treatment with antidepressant drugs when blood was drawn for therapeutic drug monitoring. The patient population consisted of 114 acutely depressed patients; 81 patients were treated with TCAs and 33 with SSRIs. The TCAs comprised amitriptyline (n = 43), clomipramine (n = 11), doxepin (n = 19) and imipramine (n = 8); the SSRIs comprised fluvoxamine (n = 14) and paroxetine (n = 19). In TCA-treated patients, the authors observed the same type of abnormalities in conduction and orthostatic hypotension as had been observed earlier. The authors also observed cases of first-degree atrioventricular block, prolonged QTc interval, and orthostatic hypotension in SSRI-treated patients. Thus SSRIs also appear to affect the cardiovascular system, which might pose a problem for patients with preexisting conduction disease. The authors observed a strong correlation between the decrease in systolic pressure and antidepressant serum concentration (except for clomipramine and paroxetine), suggesting that antidepressant serum level is a better correlate than dose.

Selected tricyclic antidepressant ingestions involving children 6 years old or less

OBJECTIVE

According to the annual report of the American Association of Poison Control Centers, tricyclic antidepressant (TCA) ingestions accounted for 15,708 exposures in 1998, of which 70% (all age groups) were treated at health care facilities (HCFs), with an estimated 2,022 children less than 6 years of age exposed. The study objective was to evaluate the manifestations, referral patterns, HCF management, and medical outcomes in pediatric patients 6 years old or less with TCA ingestions reported to a regional poison control center.

METHODS

All TCA (amitriptyline, clomipramine, desipramine, doxepin, imipramine, nortriptyline) ingestions from January 1, 1993, to December 31, 1997, involving patients aged 6 years or less managed by the poison control center were evaluated for dose, symptoms, treatments, disposition, and outcome.

RESULTS

Forty-four of 48 patients (92%) were asymptomatic. All were single-drug exposures. Forty-three patients (90%) ingested a TCA dose that was less than the normally prescribed pediatric dose (5 mg/kg). Of the five children ingesting >5 mg/kg (range 5-9.4 mg/kg), only one (5.3 mg/kg) was mildly symptomatic (drowsy) prior to admission. Thirty-one of the 48 (65%) were sent to the emergency department (dose range 0.59-9.4 mg/kg). Fourteen of the 31 were admitted for 12-24-hour observation and none subsequently developed symptoms. Twenty-three (74%) received activated charcoal (AC). There was no difference in outcome between the children who did and did not receive AC.

CONCLUSIONS

No case of significant toxicity occurred in the children who experienced unintentional TCA ingestions in this study population. None of the children in the study had toxicity at doses <5 mg/kg. Further study is necessary to develop clinical guidelines for the appropriate referral of unintentional ingestions of TCA involving children.

A nationwide survey of the management of unintentional-low dose tricyclic antidepressant ingestions involving asymptomatic children: implications for the development of an evidence-based clinical guideline

BACKGROUND

The triage of unintentional tricyclic and cyclic antidepressant ingestions involving children <6 years seems based on single cases or small studies. Walsh, in describing 2 cases involving 15-20 mg/kg ingestions, recommended hospitalizing all children ingesting tricyclic and cyclic antidepressants.

OBJECTIVE

To evaluate the patterns of triage for pediatric tricyclic and cyclic antidepressants practiced by regional poison control centers nationwide, and to determine the amount ingested (mg/kg) that resulted in referral to the emergency department, including the recommended duration of observation time for asymptomatic children. Second, to analyze the cost implications, as well as the need for a practice guideline based on severity stratification.

METHODS

We sent a survey to 44 major regional poison control centers. We reviewed Health Care Financing Administration's tricyclic and cyclic antidepressants management related costs.

RESULTS

Thirty centers responded (68%). Eighty-seven percent of all centers send children, regardless of dose ingested, to the emergency department. Four out of the 30 recommended observation based on dose in mg/ kg ingested (range >1.5-5). Recommended observation times in the emergency department varied between 6-24 hours. Twenty-seven (90%) Poison Control Centers recommended 6 hours (although one recommended doing so only after administering activated charcoal). One recommended 6-12 hours of observation and 2 Poison Control Centers recommended 24-hour observation. Only 1 center recommended obtaining tricyclic and cyclic antidepressant plasma levels.

DISCUSSION

In our review of the literature, the lowest toxic dose reported was 6.7 mg/kg. This is consistent with our Poison Control Center data over the past 5 years where no child was toxic at doses <5 mg/kg. While only 13% of the centers surveyed utilize a stratification strategy to triage pediatric tricyclic and cyclic antidepressant ingestions, the current referral patterns support evaluation based on pharmacokinetics, not worst case incidents.

CONCLUSION

This survey demonstrates that most children with tricyclic and cyclic antidepressant ingestions will be sent to the emergency department, regardless of the amount ingested. A prospective study is needed to determine the probable dose of tricyclic and cyclic antidepressant ingestions that requires observation at a health care facility.

Alternative (nonstimulant) medications in the treatment of attention-deficit/hyperactivity disorder in children

Medication to treat ADHD must be seen as part of a multimodal approach that includes education, counseling, behavioral management, and family work along with the medication. If in addition to ADHD the patient has other psychiatric disorders, they also must be treated. The stimulant medications are still the first choice in treating ADHD. Should there be reasons why they cannot be used, the TCAs become the second line of treatment. Other alternative medications such as buproprion, clonidine, and guanfacine also can be considered. This article provides information and guidelines for the use of the alternative, nonstimulant medications to treat ADHD. These medications can be used separately or in combination to reduce the primary behaviors of ADHD and comorbid conditions. The reader is encouraged to refer to reviews of the pharmaceutical company literature and the Physician's Desk Reference before initiating treatment with any of these medications.

Pharmacological treatment of depression in children and adolescents

Major depression is a common disorder during childhood and adolescence. Over the past decade, many new antidepressants have been marketed in the US. In adults, these newer agents have been shown to be as effective as the prototypic tricyclic antidepressants (TCAs). Further, when compared with the TCAs these medications are better tolerated and are safer in overdose. Although TCAs are effective in the treatment of depressed adults, controlled clinical trials have not demonstrated their efficacy in either children or adolescents. In addition, concerns about the safety of TCAs and the monoamine oxidase inhibitors has left disappointingly few pharmacological treatment options available for depressed children and adolescents. For this reason, clinicians have begun to prescribe the newer agents for this population, despite the fact that relatively little is known about their disposition, safety or effectiveness in the young. Investigators have begun to examine whether the use of newer antidepressant medications such as fluoxetine, sertraline, paroxetine, fluvoxamine, nefazodone, and venlafaxine is truly indicated for children and adolescents with major depression. Pharmacokinetic studies of sertraline, paroxetine and nefazodone have been performed in depressed youths. The results of these studies have provided data for rational administration strategies for these agents. They have also provided evidence that these agents may be well tolerated in children and adolescents. Further evidence that these agents are often well tolerated when prescribed to depressed youths has been obtained from both open-label and double-blind studies. Published studies have generally shown that open-label treatment with these newer agents often leads to symptom amelioration in paediatric patients with major depression. Since high rates of placebo response are often seen in depressed children and adolescents, results from these studies cannot be interpreted to suggest that these medications have true antidepressant efficacy in this population. At present, the results of only two such studies have been published. The results of one of these trials are difficult to interpret because of methodological considerations. The other study reported that treatment with fluoxetine was superior to placebo. This paper critically reviews what has been published about the pharmacological treatment of depressed paediatric patients and provides some guidance to the use of antidepressants in this patient population, paying particular attention to what is known about the newer antidepressants as well as considering directions for future research.

Metabolism of tricyclic antidepressants

1. Despite the considerable advances in the treatments available for mood disorders over the past generation, tricyclic antidepressants (TCAs) remain an important option for the pharmacotherapy of depression. 2. The pharmacokinetics of TCAs are characterized by substantial presystemic first-pass metabolism, a large volume of distribution, extensive protein binding, and an elimination half-life averaging about 1 day (up to 3 days for protriptyline). 3. Clearance of tricyclics is dependent primarily on hepatic cytochrome P450 (CYP) oxidative enzymes. Although the activities of some P450 isoenzymes are largely under genetic control, they may be influenced by external factors, such as the concomitant use of other medications or substances. Patient variables, such as ethnicity and age, also affect TCA metabolism. The impact of gender and related reproductive issues is coming under increased scrutiny. 4. Metabolism of TCAs, especially their hydroxylation, results in the formation of active metabolites, which contribute to both the therapeutic and the adverse effects of these compounds. 5. Renal clearance of the polar metabolites of TCAs is reduced by normal aging, accounting for much of the increased risk of toxicity in older patients. 6. Knowledge of factors affecting the metabolism of TCAs can further the development and understanding of newer antidepressant medications.

Desipramine clearance in children and adolescents: absence of effect of development and gender

OBJECTIVE

To examine the influence of development and gender on the pharmacokinetics of desipramine (DMI) in the pediatric population.

METHOD

DMI pharmacokinetic parameters were calculated from 407 routinely drawn, dose- and weight-normalized serum concentrations in 173 youths receiving DMI (90 children, 83 adolescents; 29 were female, 144 were male).

RESULTS

Mean pharmacokinetic parameters for the entire population included dose (3.78 +/- 1.51 mg/kg), weight- and dose-normalized serum concentration (45.41 +/- 47.39 [micrograms/L]/[mg/kg]), and DMI clearance (0.68 +/- 1.51 [L/kg]/hr). No between-group differences for children and adolescents were detected in dose (child, adolescent) (3.73 +/- 1.40 mg/kg, 3.83 +/- 1.68 mg/kg), weight- and dose-normalized serum concentrations (44.52 +/- 39.6 [micrograms/L]/[mg/kg], 46.34 +/- 34.89 [micrograms/L]/[mg/kg]; p = .62), and clearance (0.680 +/- 0.890 [L/kg]/hr, 0.695 +/- 1.05 [L/kg]/hr; p = .103). No between-group gender differences were detected in dose (male, female) (3.83 +/- 1.55 mg, 3.39 +/- 1.84 mg), weight- and dose-normalized serum concentrations (45.15 +/- 37.76 [micrograms/L]/[mg/kg], 47.14 +/- 34.96 [micrograms/L]/mg/kg]; p = .720), and clearance (0.699 +/- 0.89 [L/kg]/hr, 0.606 +/- 0.535 [L/kg]/hr; p = .390).

CONCLUSIONS

These results suggest that age and gender do not significantly influence DMI clearance or dose-normalized serum concentrations in the pediatric population.

Laboratory and diagnostic testing in child and adolescent psychiatry: a review of the past 10 years

OBJECTIVE

To review in a critical fashion the literature of the past decade covering diagnostic and laboratory testing in the field of child and adolescent psychiatry.

METHOD

A computerized search of articles published during the past decade was made, and selected articles are presented. Because of the paucity of articles specifically relating to minors, selected articles from adult psychiatry are cited.

RESULTS

With a few notable exceptions, few controlled studies on the specificity and sensitivity of any laboratory test for any specific disorder of behavior presenting in children have been conducted in children and adolescents. A high index of suspicion will remain the clinician's best ally in utilizing laboratory measures in the assessment of psychopathology. Nonetheless, studies have appeared that will guide the clinician as to what tests are not clinically useful.

CONCLUSION

Indications and the lack of indications for specific laboratory studies are an integral part of the knowledge base that child psychiatrists must have. Much more empirical data will need to be collected prospectively to inform the field and to move the judicious use of the laboratory from an art to a science.

Tricyclic antidepressants and cardiac autonomic control in children and adolescents

OBJECTIVE

To elucidate the effects of tricyclic antidepressants on sympathetic and vagal modulation of heart rate variability.

METHOD

Seventy-five children and adolescents (mean age 10.5 years, SD 2.0) from therapeutic and regular schools underwent challenges of paced breathing and orthostatic postural change, while heart rate was continuously recorded. Teachers completed dimensional ratings of behavior to quantity anxiety and conduct disorder. Spectral analysis of heart rate variability was utilized to decompose the postural (sympathetic) and respiratory (vagal) contributions to beat-to-beat variations in heart rate.

RESULTS

Under conditions in which cardiac vagal effects were expected to predominate, subjects medicated with tricyclic antidepressants (n = 13) showed significantly reduced vagal modulation of heart rate variability (F[5,69] = 5.23, p < .003), higher heart rates (F[5,69] = 5.54, p < .002), and higher relative sympathovagal balance (F[5,69] = 5.51, p < .002) than nonmedicated (n = 42) and medicated comparison groups (n = 20), even after controlling for the effects of age and psychopathology.

CONCLUSIONS

The relative loss of cardiac vagal control in young subjects medicated with tricyclic antidepressants, considered in the context of factors known to be associated with the development of tachyarrhythmias, presents as yet another risk, especially when coupled with factors such as maturational effects and psychopathology.

Case study: two additional sudden deaths with tricyclic antidepressants

Since 1990, there have been five reported cases of sudden death in children treated with desipramine. This case study describes the sudden deaths of two additional children treated with tricyclic antidepressants, one with desipramine, 3.3 mg/kg per day, the other with imipramine, 6 mg/kg per day and thioridazine, 1 mg/kg per day. The reports add to concerns about the use of tricyclics in children.

Cardiovascular effects of therapeutic doses of tricyclic antidepressants in children and adolescents

OBJECTIVE

Tricyclic antidepressants (TCAs) play an important role in the treatment of pediatric psychiatric disorders. Despite widespread clinical use, concerns about their possible cardiovascular risk have arisen following several published reports of sudden death associated with their use in children. Accordingly, available evidence concerning TCA-associated cardiovascular effects in children and adolescents was surveyed.

METHOD

A systematic literature search from 1967 to 1996 identified relevant pediatric studies that evaluated cardiovascular effects of TCAs.

RESULTS

Twenty-four studies involving 730 children and adolescents given imipramine, amitriptyline, desipramine, or nortriptyline were found. TCA treatment was associated with minor increases in systolic and diastolic blood pressure, in heart rate, and in the electrocardiographic (ECG) conduction parameters, PR, QRS, and QTc. Holter ECG monitoring and exercise testing also revealed minor treatment effects. Some ECG changes related to specific TCAs emerged. Few age-related ECG differences in TCA-treated children, adolescents, or adults were detected. Associations of ECG abnormalities and relatively higher serum TCA levels were found.

CONCLUSION

TCA treatment in children and adolescents, like that in adults, is associated with cardiovascular changes of uncertain, but probably minor, clinical significance. More information is needed on the contribution of other physiological conditions on the cardiovascular system during exposure to TCAs. Guidelines for using TCAs in children and adolescents are presented.

Electrocardiographic changes during desipramine and clomipramine treatment in children and adolescents

OBJECTIVE

With the increased use of tricyclic antidepressants in children, and several reports of several sudden deaths associated with desipramine (DMI) treatment, systematic study of their cardiac effects is indicated. In the present study, DMI's and clomipramine's (CMI) short-term effects on the electrocardiogram (ECG) were compared, as well as the long-term effects of CMI.

METHOD

The ECGs of 47 children and adolescents in treatment trials were examined at baseline, after 5 weeks of CMI and of DMI treatment, and during CMI maintenance (mean duration 24.6 months).

RESULTS

At 5 weeks of CMI and of DMI treatment, the heart rate, PR, QRS, and QT-corrected (QTc) intervals on ECG were significantly increased from baseline (p < .05); DMI increased PR and QRS intervals more than CMI (p < .05), and CMI increased QTc more (p < .05). Tachycardia was the most common change (36%). More patients experienced an incomplete intraventricular conduction delay during DMI treatment (23%, 9/39) than during CMI (2%, 1/47) (p < .05). Four patients (9%) acutely developed a prolonged QTc during either DMI or CMI. Long-term maintenance ECGs during CMI treatment (n = 25) were not significantly different from that at week 5, although some individuals developed or resolved specific ECG changes.

CONCLUSION

CMI and DMI both produced ECG changes typically reported for tricyclic antidepressants, and they differed on specific ECG changes. Changes in ECG measures for individuals from short to long term suggest that continued monitoring is required.

Psychopharmacology in child and adolescent psychiatry: a review of the past seven years. Part I

OBJECTIVE

To present a critical overview of the literature published in the past 7 years on the efficacy and safety of psychoactive agents in mental retardation with associated psychiatric disorders, autistic disorder, Tourett's disorder, and attention-deficit/hyperactivity disorder.

METHOD

Double-blind and placebo-controlled clinical trials and open studies were reviewed and selected reports presented.

RESULTS

The literature review reveals that progress has been made in the psychopharmacological treatment of the above conditions. This is partly because more studies use larger sample sizes and a narrower age range of diagnostically homogeneous patients and use a more sophisticated methodology than in previous years. Greater attention is being paid to a critical assessment of psychoactive agents and to their safety, to the efficacy as well as to the effectiveness of drugs. The 5-year National Plan for Research on Child and Adolescent Mental Disorders (1991) based on the Institute of Medicine Report (1989) already has had a significant impact on psychophamacology research.

CONCLUSIONS

Advances in methodology, initiatives of the National Institute of Mental Health, and the advent of DSM-IV should continue to enhance research and improve pharmacotherapy in clinical practice.

A naturalistic study of 24-hour electrocardiographic recordings and echocardiographic findings in children and adolescents treated with desipramine

OBJECTIVE

Recent studies assessing cardiovascular effects of desipramine (DMI) in pediatric patients consistently have found small, clinically benign, but statistically significant, increases in heart rate and electrocardiographic (ECG) conduction parameters. However, single, routine ECG recordings cannot fully assess potential infrequent rhythm disturbances.

METHOD

We analyzed data from 24-hour ECG monitoring, two-dimensional Doppler echocardiography, and expert clinical cardiac examination of DMI-treated patients. Subjects were 71 children (N = 35) and adolescents (N = 36) receiving long-term treatment (means +/- SD = 1.5 +/- 1.2 years, median = 1.0 year) with DMI (means +/- SD = 3.5 +/- 1.6 mg/kg).

RESULTS

Compared with previous observations in untreated healthy children. DMI-treated patients had significantly lower rates of sinus pauses and junctional rhythm, but significantly higher rates of single or paired premature atrial contractions and runs of supraventricular tachycardia. There was an association between DMI serum levels and paired premature atrial contractions, but no other associations were detected.

CONCLUSIONS

These findings support the impression from previous ECG studies that DMI-associated cardiac effects in pediatric patients are quite benign. Nevertheless, it remains to be ascertained whether even minor cardiac abnormalities may predict later, evidently rare, adverse cardiovascular effects that may include sudden death.