Calcium channel blockers and beta blockers in pediatric supraventricular tachycardia.

INTRODUCTION: Supraventricular tachycardia (SVT) is a common pediatric arrhythmia. Beta blockers (BBs) and calcium channel blockers (CCBs) are used for treatment despite little data examining their use. We describe the prescriptive tendencies, efficacy, and tolerability of BBs and CCBs used in the treatment of pediatric SVT. METHODS AND RESULTS: This is a multicenter retrospective cohort study from three academic children's hospitals. Individuals aged 1-21 years at time of SVT diagnosis initiated on a BB or a CCB between 01/01/2010 and 12/31/2020 were included. Exclusion criteria were pre-excitation, ectopic atrial tachycardia, and hemodynamically significant heart disease. Demographic, comorbidity, symptomatology, and medication data were collected. Treatment success was defined using a composite data abstraction tool. Of 164 patients, 151 received a BB and 13 received a CCB. The success rate on the initial dosage was 46% for both BB and CCB; the success rate following dosage adjustments was also comparable for BBs (98/151, 65%) and CCBs (9/13, 69%). While 27 (18%) BB patients experienced intolerable side effects, no CCB patient did. CONCLUSION: Treatment with a BB or CCB was successful in half of patients. BBs were prescribed more frequently than CCBs but were associated with more side effects.

Outcomes of Infant Supraventricular Tachycardia Management Without Medication.

Most infants presenting with supraventricular tachycardia (SVT) are treated with an antiarrhythmic, primarily to prevent unrecognized future episodes that could lead to tachycardia-induced cardiomyopathy. A common practice at our institution is to not treat after the first presentation of infant SVT and instead educate parents on heart rate monitoring and reasons to present to care. The goal of this study was to evaluate the outcomes of non-pharmacologic treatment of infant SVT at first presentation and compare to outcomes of infants treated with an antiarrhythmic. This was a retrospective single center study of all infants presenting with a first episode of SVT from 2014 to 2021. Excluded were patients with a non-reentry type tachyarrhythmia, atrial flutter, long-RP tachycardia, congenital heart disease, or abnormal ventricular function. Sixty-four infants were included in the study. Thirty-six were managed without an antiarrhythmic. SVT recurred in 28% of the non-treatment group vs 50% in those treated with antiarrhythmics, p = 0.12. Of the patients admitted to the hospital, those in the non-treatment group had a shorter length of stay, 1(IQR 1-1) vs 3(IQR 2-4) days, p < 0.01. Non-treated patients were less likely to present to the emergency department for recurrent SVT, 6% vs 32%, p < 0.01. Neither group had a patient develop tachycardia-induced cardiomyopathy. For infants with structurally and functionally normal hearts, non-treatment combined with parental education after the first episode of SVT does not lead to worse outcomes. This approach avoids the burden of medication administration in an infant and may have the added benefit of empowering parents to feel comfortable managing clinically insignificant tachycardia at home.

Effect of treadmill exercise stress testing on troponin levels in children and adolescents.

BACKGROUND: Chest pain is a common complaint among paediatric patients and cardiac troponin (cTn) level is often part of the initial emergency department evaluation. It is well known that after intense endurance exercise cTn levels can be elevated in patients with otherwise healthy hearts, however the effect shorter duration exercise has on cTn levels in this population is not known. OBJECTIVE: Determine the behaviour of cTn levels in healthy children and adolescent patients after short burst, high-intensity aerobic exercise. METHODS: Patients without haemodynamically significant heart disease referred for a treadmill exercise stress test (EST) were recruited over a 6-month period. cTn levels were measured prior to exercise and 4 hours after exercise. RESULTS: Thirteen patients enrolled. Indications for EST were exertional syncope (six), chest pain (four), and long QT syndrome (three). The median exercise time was 12.9 (9.9-13.7) minutes with an average endurance at the fiftieth percentile for age and maximum heart rate rose to an average of 92 (74-98)% of the predicted peak for age. cTn levels prior to exercise were undetectable in all patients. There was no cTn rise in any patient after exercise. There were no ischaemic changes or arrhythmias on exercise electrocardiograms. CONCLUSION: Serum cTn levels do not rise significantly in healthy children after short duration, high-intensity aerobic exercise. Physicians evaluating paediatric patients with an elevated cTn level after less than prolonged strenuous activity likely cannot attribute this lab value solely to exercise and may need to undertake further cardiac investigation.

Electrocardiogram changes in pediatric patients with myocarditis.

BACKGROUND: It is traditionally taught that pediatric patients with myocarditis almost always have an abnormal electrocardiogram (ECG) at presentation. However, there has never been a study to objectively evaluate ECG changes in pediatric myocarditis patients compared to healthy controls or explore if specific ECG changes correlate with clinical outcomes. METHODS: Pediatric patients diagnosed with acute myocarditis were age and sex matched 1:2 with healthy controls in this retrospective case-control study spanning a seven-year period. ECGs from presentation through discharge were interpreted by electrophysiologists blinded to the patients' diagnoses. RESULTS: Thirty-nine patients with myocarditis were identified. Twenty-eight (72%) had an abnormal ECG at presentation, 11 (28%) had a completely normal ECG. In this second group, six patients had an abnormal ECG at some point during their hospital course for a total of 34 (88%). Myocarditis patients who had an abnormal ECG at presentation spent more time in the hospital, 5 (2-19) versus 2 ((1-3) days (p < 0.01), and in the ICU, 1 (0-6) versus 0 (0-1) days (p < 0.01). Myocarditis patients were more likely to have ST elevation on their ECG compared to control patients (41% versus 17%, p < 0.01). Patients with ST elevation at presentation had a higher peak troponin level, 18.4 (5.8-31.0) versus 7.7 (0-19.1) ng/ml, (p < 0.01). CONCLUSIONS: Over a quarter of patients with myocarditis had a normal ECG at presentation to the emergency department. Patients with an abnormal ECG at presentation spent more time in the hospital. The presenting ECG, particularly the presence of ST elevation, may correlate with other clinical markers and help direct early management decisions.