What is the best course of action for a child with tachycardia (rapid heart rate) and substernal chest pain lasting two weeks?

Urgent Cardiology Evaluation and ECG Required for Suspected Supraventricular Tachycardia

A child presenting with tachycardia and substernal chest pain lasting two weeks requires immediate pediatric cardiology consultation, 12-lead ECG, and echocardiography to rule out supraventricular tachycardia (SVT) or other serious cardiac arrhythmias. 1, 2

Immediate Assessment

The two-week duration of symptoms suggests a persistent or recurrent arrhythmia rather than an acute emergency, but cardiac causes must be excluded urgently:

• Obtain a 12-lead ECG immediately to differentiate sinus tachycardia from SVT or other arrhythmias 1
• Assess hemodynamic stability: Check for signs of poor perfusion, altered mental status, hypotension, or acute heart failure 1
• Measure vital signs carefully: Heart rates >150 bpm in children are more likely to represent true arrhythmia rather than physiologic sinus tachycardia 1

Key Diagnostic Considerations

The combination of tachycardia and chest pain in children most commonly indicates an arrhythmia when cardiac disease is present 2:

• Supraventricular tachycardia (SVT) is the most common arrhythmia causing chest pain in children 2, 3
• Ventricular tachycardia, though less common, can present with chest pain and carries higher mortality risk 2
• Pericarditis should be considered, especially if pain is positional (worse lying down, relieved sitting forward) 4
• Anomalous coronary arteries are rare but life-threatening causes 5

Essential Workup

Beyond the immediate ECG, the following are required 2, 5:

• Echocardiography to assess cardiac structure, function, and rule out pericardial effusion 5, 4
• 24-hour Holter monitoring if initial ECG is normal but symptoms persist, to capture paroxysmal arrhythmias 2
• Exercise stress testing may be indicated if symptoms are exertional 2
• Inflammatory markers (CRP, ESR) if pericarditis is suspected 4

Management Based on Findings

If SVT is Confirmed:

• For hemodynamically stable patients: Attempt vagal maneuvers first (ice to face in infants, Valsalva in older children) 1
• Adenosine is first-line pharmacologic therapy (6 mg rapid IV push, then 12 mg if needed) if IV access is available 1
• Consultation with pediatric electrophysiology is strongly recommended before initiating treatment in stable patients 1
• Consider catheter ablation for recurrent symptomatic SVT in school-age children 3

If Pericarditis is Suspected:

• Look for pericardial friction rub on auscultation, positional chest pain, and diffuse ST-elevation on ECG 4
• Indomethacin and colchicine are first-line treatments for pediatric pericarditis 4

If Sinus Tachycardia:

• Search for and treat underlying causes (fever, dehydration, anemia, anxiety) rather than treating the heart rate itself 1
• No specific cardiac treatment is required if this is physiologic 1

Critical Pitfalls to Avoid

• Do not dismiss chest pain in children as benign without cardiac evaluation when accompanied by tachycardia 2, 6
• Do not assume sinus tachycardia without ECG confirmation—SVT can be misidentified clinically 1
• Do not delay cardiology referral for persistent symptoms lasting two weeks 5
• Children with prior cardiac surgery are at particularly high risk for arrhythmias and require lower threshold for investigation 2
• Syncope with tachycardia indicates severe hemodynamic compromise and requires urgent intervention 3

Disposition

Given the two-week duration, this child requires same-day pediatric cardiology evaluation rather than emergency department presentation, unless signs of hemodynamic instability develop 5. Most cardiac causes of chest pain in children can be evaluated effectively in the ambulatory cardiology setting with appropriate diagnostic testing 5.