Initial Management of Pediatric Tachycardia at 250 bpm
B. Electrocardiogram is the initial step for a child presenting with palpitations and a heart rate of 250 bpm. 1
Immediate Diagnostic Approach
Obtain a 12-lead ECG immediately to document the rhythm, evaluate QRS duration, assess P-wave morphology and relationship to QRS complexes, and distinguish between supraventricular tachycardia (SVT), sinus tachycardia, atrial flutter, or ventricular tachycardia. 1 This is the critical first step before any intervention, as the ECG findings will determine the entire management pathway.
Why ECG Takes Priority Over Echocardiogram
A 12-lead ECG during tachycardia is crucial for definitive diagnosis and should be obtained before any treatment that terminates the rhythm. 1 At 250 bpm, this heart rate far exceeds physiologic sinus tachycardia (upper limit ~220 minus age), making a primary arrhythmia highly likely. 1
The ECG will immediately reveal whether this is narrow-complex SVT (most common in children), wide-complex tachycardia (requiring different management), or another mechanism. 1, 2
Echocardiography is recommended to exclude structural heart disease, but this comes after the initial ECG diagnosis and is part of the comprehensive workup, not the immediate first step. 1
Clinical Context for This Heart Rate
At 250 bpm, this child most likely has supraventricular tachycardia (SVT), which is the most common symptomatic arrhythmia in children. 2, 3 The typical heart rate range for SVT is 150-250 bpm. 4
Re-entry tachycardias are the most common form in pediatrics, with tachycardia mediated by accessory pathways representing >70% of SVT in infants and approximately 55% in adolescents. 5
The age at presentation matters significantly: if SVT starts in the first months of life, it disappears in 80% of cases within the first year; if it starts later, spontaneous remission occurs in only 15-20% of patients. 2
Simultaneous Assessment While Obtaining ECG
While preparing for and obtaining the ECG, you should simultaneously:
Determine hemodynamic stability first, as this dictates the entire management pathway. 1 Look for signs of shock, altered mental status, chest pain, or respiratory distress.
Attach a cardiac monitor, evaluate blood pressure, provide supplementary oxygen if needed, and establish IV access if the patient is stable. 1
If the patient shows signs of hemodynamic instability, proceed immediately to synchronized cardioversion (starting at 50-100 J for SVT) without delaying for the full diagnostic workup. 1
Critical Pitfall to Avoid
Do not administer digoxin or verapamil for treatment of sustained tachycardia in infants when ventricular tachycardia has not been excluded as a potential diagnosis. 5 This is why the ECG must come first—to definitively characterize the rhythm before any pharmacologic intervention.
Next Steps After ECG
Once the ECG confirms the diagnosis (likely SVT given the rate):
For stable patients with regular narrow-complex SVT, adenosine may be considered (initial doses of 150-250 mcg/kg in children, which is higher than adult dosing). 5
Echocardiography should then be performed to exclude structural heart disease including hypertrophic cardiomyopathy, dilated cardiomyopathy, valvular abnormalities, and coronary artery anomalies. 1
Immediate cardiology referral is required for documented sustained SVT, wide complex tachycardia of unknown origin, syncope during tachycardia, or pre-excitation (Wolff-Parkinson-White syndrome) on ECG. 1