A Case of Neonatal Atrial Flutter

Table of Content

Author: OUNG Savly is a pediatric cardiologist, Head of pediatric CICU, Kantha Bopha Children’s Hospital, Phnom Penh, Cambodia.

The authors have obtained the consent of the parents in order to report this case.

Contact information: oungsavly007@gmail.com

No conflict of interest to disclose.

Background

Atrial flutter is rare in children. It can occur in the following settings:

Atrial flutter and intra-atrial reentrant tachycardia (IART) following cardiac surgery - primarily seen in children with a history of previous cardiac surgery, particularly following the Mustard, Senning, or Fontan procedures.
Neonatal atrial flutter:
- Can occur in fetuses and neonate with structurally normal hearts.
- The mechanism for atrial flutter in this setting is thought to be similar to adults, involving macro-reentry around the tricuspid valve, although definitive studies have not been performed.
- Neonatal atrial flutter rarely recurs following cardioversion with or without medical treatment.

Case Description

The infant, a 3-month-old baby girl born full-term, weighing 5 kilograms, presented with critical illness characterized by dyspnea during feeding. She was diagnosed and treated for bronchiolitis and cardiac beriberi. She was delivered at 39 weeks to a healthy mother, with the pregnancy and delivery being uncomplicated. No resuscitation was needed at birth. She had satisfactory Apgar scores and weighed 3300 g at birth.

At 2 months of age, her mother observed that she experienced difficulty in breathing, notably during feeding. In the month leading up to her admission to our cardiac center, she had sought medical evaluations from private clinics, but the issue remained unresolved, and the infant's clinical condition progressively worsened.

Upon arrival, the examination revealed an irregular and rapid heart rate accompanied by moderate dyspnea. Hepatomegaly was evident, with the liver palpable approximately 3cm below the right costal margin. She exhibited no fever and remained hemodynamically stable.

Figure 1: Chest radiography outlining a large cardiac silhouette and pulmonary edema.

Telemetry

Telemetry outlining the atrial flutter

Back in sinus rhythm once paced.

ECG

12-lead ECG while in atrial flutter. Saw-tooth appearance may be partially observed, although often revealed when attempting adenosine - not done in this current ECG.

Back in Sinus rhythm (positive P in lead I and aVF). Signs of left atrial enlargement in lead II. Signs of LV hypertrophy.

Echocardiographic evaluation

Parasternal long axis view outlining the significant LV diltation and failure in the context of flutter. The aortic valve is seen open and close (outlining that there is some remaining ejection). The mitral valve opens and close, outlining that there is some filling.

Apical view outlining the significant LV dilation and dysfunction. There is mild to moderate mitral insufficiency by coulor.

The infant was diagnosed with neonatal atrial flutter. After administering sedation with midazolam and ketamine, we successfully restored sinus rhythm using direct current synchronized cardioversion at 0.5j/kg. The infant showed marked improvement with reduced dyspnea, particularly during feeding. However, her cardiac function had yet to fully recover. Consequently, she was treated with digoxin, an ACE inhibitor, and spironolactone to address her cardiac failure induced by prolonged tachycardia. The infant was discharged five days later, following comprehensive education provided to the caregivers about monitoring for rapid heart rates to ensure timely management.

Discussion

Managing an infant or child presenting with narrow complex tachyarrhythmia is particularly challenging due to the often unidentified mechanism of the tachycardia. Direct current cardioversion stands as the highly recommended primary therapy. Following the resolution of the arrhythmia, patients typically undergo ECG and ambulatory rhythm monitoring for an additional year. Recurrences are infrequent; however, if an event recurs, a thorough evaluation for intrinsic structural, functional, or channelopathy conditions is imperative.

Conclusion

Neonatal atrial flutter, though uncommon, warrants prompt identification and intervention. Timely management can mitigate the risk of heart failure and shorten hospital stay durations. Importantly, parents should be educated on monitoring their infant's heart rate and identifying early symptoms of congestive heart failure.

Bibliography

- UptoDate, "Atrial Tachyarrhythmias in Children: Neonatal Flutter"