Niu MC, et al. - The links between arrhythmias, anatomy, and outcomes were investigated in a large Heterotaxy Syndrome (HS) cohort. In this patient population, arrhythmias of clinical significance were commonly detected. An association of bradyarrhythmias with left atrial isomerism (LAI) was evident. In addition, the occurrence of tachyarrhythmia relied more on hemodynamic and anatomical factors rather than isomerism subtype. Data indicated an association of tachyarrhythmias, but not of bradyarrhythmias, with death or need for transplant.

Methods

• This single center retrospective review included patients diagnosed with HS ≤ 21 years of age.

Results

• A total of 337 patients were included.
• Findings demonstrated that during a median follow-up period of 7 years [IQR: 2 – 16 years]), 129 (38%) patients had ≥1 clinically significant rhythm disturbance: tachyarrhythmias in 75 (22%), bradyarrhythmias in 29 (9%), 25 (7%) had both.
• Multivariate analysis suggested that following factors were associated with tachyarrhythmia: at least moderate atrioventricular valve regurgitation (HR 1.66, CI 1.11—2.50), single ventricle anatomy (HR 2.30, CI 1.09—4.85) and pulmonary venous obstruction (HR 2.33, CI 1.45—3.76).
• No association of isomerism subtype with tachyarrhythmias was reported.
• In adjusted and unadjusted analyses, association of bradyarrhythmias (symptomatic sinus/atrial bradycardia and high grade or complete heart block) with left atrial isomerism (LAI), compared to right atrial isomerism (HR 7.12, CI 3.01—16.9), was demonstrated.
• Researchers found that the overall transplant-free survival of the cohort was 66%.
• Data reported an association of tachyarrhythmias, but not of bradyarrhythmias, with mortality or need for transplant (HR 2.24, CI 1.45—3.46).