Assessment of left atrial function in children with supraventricular arrhythmias

Supraventricular arrhythmias (SA) constitute a common problem in a paediatric population. The most common supraventricular arrhythmia substrates in children are accessory pathways (AP) and atrioventricular nodal reentrant tachycardia (AVNRT). Although SA are generally considered benign, they can significantly affect quality of life and the presence of preexcitation increases risk of sudden cardiac death, making it an important area of research. Speckle-tracking echocardiography is an objective, more detailed method of cardiac function assessment, however left atrial strain (LAS) is still not widely used in children, particularly in the field of cardiac dysrhythmias. The left atrium is believed to be responsible for 30% of stroke volume, therefore, we decided to objectively measure the left atrial function in children with SA to see whether SA could affect the cardiac contractility.

The aim of the study was to determine whether the left atrial function is impaired in children with SA and structurally normal hearts.

We conducted a prospective study of children with documented supraventricular arrhythmias and no history of other heart condition who were referred for electrophysiological study (EPS) in our centre. The arrhythmia substrates were confirmed during the EPS and only the patients with APs or ANRT were included into the study. We compared the results with 33 age- and sex-matched healthy individuals. Transthoracic echocardiography was used to assess their left atrial (LA) function. All subjects underwent conventional echocardiography with an assessment of the following parameters: LA size in parasternal long-axis view, and LA area from 4-chamber apical view. Speckle tracking echocardiography was used additionally to assess LA reservoir (LASr) and contractile (LASct) strain.

41 children aged 9-17 (mean 13; ±2.6) were included in the study group, 17 patients had AVNRT and 24 had AP (12 symptomatic and 12 asymptomatic). The control group consisted of 33 children (aged 8-17 years; mean 13± 2.4) with no cardiac disorder. The study group showed statistically significant lower values of both LASr (38.9%±7.9 vs 45.5%VSD 11.1, p<.005) and LASct (7.3%±3.8 vs 11%±4,0, p<.0001) as well as bigger value of LA area (12.6cm2±2.4 vs 10.2cm2±1.64, p<.0001). No difference in terms of LA size in PLAX was observed.

LA strain measurement is a sensitive method of LA function assessment and may be used in children with SA. The LA function in children with AVNRT and APs and otherwise healthy hearts is impaired.

LAS in a child with symptomatic AP