Does a 13-year-old female with mild Multisystem Inflammatory Syndrome in Children (MIS-C) and initial elevated cardiac enzymes, including troponin and B-type Natriuretic Peptide (BNP), and inflammatory markers, who showed significant improvement after treatment with Intravenous Immunoglobulin (IVIG) and a steroid taper, require a repeat echocardiogram at her first outpatient follow-up 2 weeks after diagnosis and treatment, given a normal initial echo?

Cardiac Follow-up for MIS-C: Repeat Echocardiogram at First Outpatient Visit

A repeat echocardiogram is recommended at the first outpatient follow-up visit (2 weeks after diagnosis) for this 13-year-old female with mild MIS-C, despite normal initial echo and improvement in cardiac enzymes and inflammatory markers. 1, 2

Rationale for Repeat Echocardiogram

• The American College of Rheumatology guidelines recommend echocardiograms be repeated at a minimum of 7-14 days and 4-6 weeks after initial presentation in all children with MIS-C 1, 2
• This recommendation applies even to patients with:
  • Normal initial echocardiogram
  • Mild disease
  • Improvement in cardiac biomarkers (troponin, BNP)
  • Resolution of inflammatory markers

Cardiac Monitoring Protocol for MIS-C

Initial 2-Week Follow-up (Current Visit)

• Repeat echocardiogram to assess:
  • Ventricular function (ejection fraction)
  • Coronary artery dimensions with z-scores
  • Valvular function
  • Presence of pericardial effusion 2
• Laboratory assessment:
  • Troponin and BNP levels (continue until normalized)
  • Inflammatory markers (CRP, ESR)
  • Electrocardiogram to assess for conduction abnormalities

Subsequent Follow-up (4-6 Weeks)

• Additional echocardiogram regardless of findings at 2-week visit 1, 2
• Continued monitoring of any abnormal cardiac biomarkers until normalization

Importance of Cardiac Monitoring in MIS-C

Cardiac Complications in MIS-C

• Cardiac involvement is common in MIS-C, occurring in 20-55% of cases 1
• Potential cardiac sequelae include:
  • Left ventricular dysfunction (even if initially normal)
  • Coronary artery dilation or aneurysms (can develop after initial presentation)
  • Conduction abnormalities (19% prevalence of first-degree AV block) 3
  • Pericardial effusion

Evidence Supporting Follow-up Imaging

• Research shows that cardiac abnormalities may persist or develop after the acute phase:
  • A 2023 study found 61.3% of MIS-C patients had at least one cardiac abnormality on MRI performed 3+ months after diagnosis, even when echocardiograms had normalized 4
  • Another study showed that while most cardiac function normalizes by 6-8 weeks, some patients may develop persistent coronary abnormalities 5

Special Considerations

When More Frequent Monitoring Is Needed

• If the repeat echocardiogram at 2 weeks shows any abnormalities:
  • Schedule more frequent echocardiograms (every 2-4 weeks until normalized)
  • Consider cardiac MRI at 2-6 months if there is evidence of LV dysfunction 2

When to Consider Additional Testing

• Holter monitoring if conduction abnormalities are detected on ECG 2
• Cardiac MRI at 2-6 months if:
  • Significant LV dysfunction develops (EF <50%)
  • Persistent cardiac symptoms despite normal echocardiogram 2, 4

Common Pitfalls to Avoid

• Do not rely solely on normalization of cardiac biomarkers (troponin, BNP) as indicators of cardiac recovery
• Do not assume that a normal initial echocardiogram excludes the possibility of developing cardiac complications later
• Do not discharge from cardiac follow-up too early (minimum follow-up period should be 6-8 weeks with at least two echocardiograms)

Despite this patient's mild presentation, normal initial echo, and improvement in cardiac enzymes, adherence to the recommended follow-up protocol with repeat echocardiogram at the 2-week visit is essential to ensure complete cardiac recovery and detect any late-developing complications.