Objective:

To evaluate postinfectious cardiac function and its relationship with symptoms in patients aged 0 to 21 years at baseline and 12-month follow-up.

Approach:

• Study Design: A prospective, multisite, observational study conducted by Children’s National Hospital and the National Institute of Allergy and Infectious Diseases.
• Participants: Of 852 participants completing baseline visits, 830 were analyzed: 683 infected and 147 uninfected.
• Echocardiographic Analysis: Automated endocardial tracing was used for strain analysis, with generalized estimating equations accounting for intrafamily clustering, age, and sex.
• Follow-Up: Twelve-month follow-up was completed by 550 infected and 121 initially uninfected participants; 48 remained uninfected and 73 crossed over after becoming infected.

Key Findings:

• Cardiac function did not differ between infected and uninfected participants at baseline or 12 months.
• Impaired function was rare. Among participants with abnormal baseline values and follow-up data, fractional shortening and several diastolic and strain measures improved (P < .001 for each reported improvement).
• Among crossover participants, measured cardiac indices did not change significantly after infection, except for increased left ventricular global longitudinal strain (P = .007), which was not considered clinically significant. One crossover participant developed abnormal right ventricular strain measures.
• Participants with obstructive pulmonary function test results had less negative right ventricular free-wall longitudinal strain than those with normal results at baseline (−25.2 ± 5.4% vs −27.6 ± 4.4%; P = .02) and 12 months (−25.2 ± 2.0% vs −28.0 ± 3.9%; P = .02).

Interpretation:

Infected participants frequently reported cardiac, constitutional, and respiratory symptoms, but left and right ventricular strain measures did not differ between participants with and without symptoms at baseline or 12 months.

Limitations:

• The authors identified attrition at the 12-month follow-up as a limitation.
• Participants with and without 12-month follow-up did not differ in baseline abnormal echocardiographic parameters or symptoms, except for exertional malaise.
• Intraobserver and interobserver reproducibility analyses were not performed.

Conclusion:

Cardiac dysfunction was rare, and cardiac function did not differ between infected and uninfected participants at baseline or 12 months. Reported post-COVID-19 symptoms were not associated with differences in ventricular strain measures.