What virus causes tachycardia in a 7-week-old infant?

From the Guidelines

Respiratory Syncytial Virus (RSV) is a major cause of acute lower respiratory tract infection in infants and young children worldwide, and can lead to tachycardia in a 7-week-old infant. According to a recent study published in the American Journal of Obstetrics and Gynecology in 2022 1, RSV is a significant concern for infants, particularly those under 2 months old, who account for 44% of RSV hospitalizations. The study highlights the vulnerability of infants to RSV infection during early life, with very preterm infants being three times more likely to be hospitalized than infants born at term.

Some key points to consider when evaluating the cause of tachycardia in a 7-week-old infant include:

• RSV infection is mainly treated with supportive care, although palivizumab, a humanized monoclonal antibody, has been shown to be effective in reducing hospitalization among high-risk children aged <24 months 1
• Maternal vaccination is believed to be a safer means of conferring immunity in infants against RSV, but no vaccines have yet been licensed for use 1
• The F glycoprotein is a promising vaccine target, with recent Phase 3 trials investigating the efficacy of recombinant RSV fusion nanoparticle vaccines 1

In the context of a 7-week-old infant presenting with tachycardia, it is essential to consider RSV as a potential cause, particularly if the infant is showing signs of respiratory distress or other symptoms of lower respiratory tract infection. Parents should seek immediate medical attention if their infant has a heart rate consistently above 160-180 beats per minute, especially if accompanied by poor feeding, lethargy, respiratory distress, or fever. Treatment is primarily supportive care, including maintaining adequate hydration, fever control, and close monitoring of vital signs 1.

From the Research

Virus Causing Tachycardia in 7-Week-Old Infants

• The virus that can cause tachycardia in 7-week-old infants is the Respiratory Syncytial Virus (RSV) 2.
• RSV is a common cause of respiratory infections in children and has been associated with abnormal supraventricular tachycardia (SVT) in infants 2.
• A study published in 2016 reported a case of a 7-week-old infant who presented with respiratory distress and persistent tachycardia, which was later diagnosed as atrial flutter-induced cardiomyopathy 3.
• However, the study did not specify the cause of the atrial flutter, and further research is needed to determine if RSV is a potential cause of tachycardia in this age group.

Association between RSV and Tachycardia

• A study published in 1994 found that RSV infections in infants may be associated with unusual atrial tachycardias, including ectopic atrial tachycardia, chaotic atrial tachycardia, and atrial flutter 2.
• The study suggested that RSV infections may be a cause of tachycardia in infants, particularly those with structurally normal hearts 2.
• However, the exact mechanism by which RSV causes tachycardia is not fully understood and requires further research.

Prevention and Treatment of RSV-Related Tachycardia

• Palivizumab, a humanized monoclonal antibody, has been shown to be effective in preventing serious lower respiratory tract infections caused by RSV in high-risk infants 4, 5.
• However, the use of palivizumab in preventing RSV-related tachycardia is not well established, and further research is needed to determine its effectiveness in this context.
• Treatment of RSV-related tachycardia typically involves rate control and synchronized electrocardioversion, as seen in the case report published in 2016 3.