What is the recommended cardiac workup for a pediatric patient with a suspected cardiac condition, considering their age, medical history, and symptoms such as chest pain and shortness of breath?

Pediatric Cardiac Workup: A Structured Approach

The cardiac workup for pediatric patients with suspected cardiac conditions should begin with electrocardiogram (ECG) and echocardiography as the primary diagnostic modalities, with cardiac catheterization reserved for specific indications where noninvasive imaging is insufficient. 1, 2

Initial Clinical Assessment

History and Physical Examination Priorities:

• Symptom characterization: Document respiratory status, feeding intolerance, diaphoresis with feeding, growth patterns, exercise intolerance, and chest pain characteristics (onset, duration, exertional relationship) 1
• Age-specific considerations: Neonates and infants require assessment for ductal-dependent lesions, while older children need evaluation for acquired conditions like myocarditis or cardiomyopathy 1
• Physical examination findings: Measure upper and lower extremity blood pressures (coarctation screening), assess precordial impulse, identify thrills, characterize murmurs (frequency, pitch, duration, quality, location, radiation), evaluate femoral pulses and perfusion 1
• Vital signs assessment: Include oxygen saturation, respiratory rate, and blood pressure in all four extremities 1

Core Diagnostic Studies

Electrocardiogram (ECG):

• Mandatory for all suspected cardiac cases to assess QRS axis, atrial enlargement, right ventricular hypertrophy (RVH), left ventricular hypertrophy (LVH), and ST-T wave abnormalities 1
• Arrhythmia detection: Essential for identifying acutely symptomatic arrhythmias requiring immediate intervention 1, 3

Echocardiography:

• Primary structural assessment tool that can adequately evaluate most pediatric cardiac conditions noninvasively 2
• Specific assessments include: Atrial septal defects (location, size), ventricular septal defects (location, size, LV-RV gradient), patent ductus arteriosus (size, Ao-PA gradient), LV size and function, RV size, and pulmonary hypertension 1, 4
• Accuracy: In a prospective study of 209 pediatric open-heart procedures, echocardiography alone provided adequate preoperative diagnosis in 68% of cases, with only 8.5% having additional intraoperative findings 2
• Limitations recognition: Understand when sedation is required and when alternate imaging modalities (MRI, CT) are necessary 1

Chest Radiograph:

• Indicated based on: Patient age, examination findings, and suspicion for pulmonary process 1
• Assess for: Cardiomegaly, pulmonary vascular markings, and pulmonary edema 1

Age-Specific Critical Presentations

Neonatal Period (0-28 days):

• Ductal-dependent lesions require immediate recognition: Left-sided obstructive lesions (hypoplastic left heart syndrome, critical aortic stenosis, coarctation), right-sided obstructive lesions (critical pulmonary stenosis, pulmonary atresia) 1
• Immediate intervention: Initiate prostaglandin E1 (PGE1) for ductal-dependent circulation 1, 5
• Critical caveat: Recognize when PGE1 may be detrimental (e.g., pulmonary venous obstruction) 1
• Other neonatal emergencies: D-transposition of great arteries, total anomalous pulmonary venous connection with obstruction, anomalous origin of left coronary artery 1

Infants and Older Children:

• Acquired conditions: Myocarditis, cardiomyopathy (including rheumatic fever, Kawasaki disease), endocarditis, pericardial effusion 1
• Hypercyanotic episodes: "Tet spells" in tetralogy of Fallot patients require immediate recognition and management 1
• Arrhythmias: Acutely symptomatic arrhythmias necessitate immediate ECG and treatment 1, 3

Advanced Diagnostic Modalities

Cardiac Catheterization:

• Reserved for specific indications: When noninvasive imaging is insufficient, for hemodynamic assessment in pulmonary hypertension, or when intervention is planned 1, 2
• Not routinely required: 68% of pediatric cardiac surgeries can proceed based on echocardiography alone 2
• Invasive pressure measurements: Gold standard for pulmonary hypertension diagnosis and acute vasoreactivity testing 4

Advanced Imaging:

• Cardiac MRI: For complex anatomy, ventricular function assessment, and when echocardiographic windows are inadequate 1
• Arterial blood gas analysis: Essential for assessing oxygen delivery and acid-base status in critically ill patients 1

Laboratory Studies

Cardiac Biomarkers:

• Troponin testing: Indicated for suspected myocarditis, myocardial infarction (rare in pediatrics), or acute coronary syndrome 3
• BNP/NT-proBNP: Useful for heart failure assessment 3

Additional Testing:

• Complete blood count, metabolic panel: For systemic assessment 3
• Inflammatory markers: When myocarditis or rheumatic fever suspected 1

Critical Pitfalls to Avoid

Delayed Recognition of Ductal-Dependent Lesions:

• Neonates presenting with shock or cyanosis must be evaluated immediately for ductal-dependent circulation 1
• Do not delay PGE1 initiation while awaiting echocardiography if clinical suspicion is high 1, 5

Misinterpretation of Echocardiographic Variables:

• Congenital heart disease patients require special physiological considerations that differ from standard pediatric guidelines 4
• Single ventricle physiology, univentricular hearts, and complex shunts need specialized interpretation 4

Overlooking Sudden Cardiac Arrest Risk:

• Patients with chest pain and shortness of breath require evaluation for channelopathies, cardiomyopathies, and myocarditis 3
• ECG is mandatory even in seemingly benign presentations 3

Consultation and Follow-Up

Pediatric Cardiology Consultation:

• Immediate consultation required for: Suspected critical congenital heart disease, acutely symptomatic arrhythmias, acute heart failure, or hemodynamic instability 1
• Timely consultation for: Abnormal ECG findings, structural abnormalities on echocardiography, or persistent symptoms 1

Follow-Up Intervals:

• Set appropriate intervals based on diagnosis severity, with more frequent monitoring for unstable or complex lesions 1
• Coordinate care with surgical or interventional teams and primary care providers 1