Background: In the general population, atrial fibrillation (AF) is thought to originate from the left atrium (LA). Left-sided echocardiographic parameters associated with AF have been described, including LA and right atrium (RA) enlargement, with a RA/LA ratio <1. Right-sided pathologies are frequent in congenital heart disease (CHD) and AF is a well known complication. Our objectives were to compare prevalence and echographic parameters associated with AF in CHD patients with right-sided pathologies versus left-sided pathologies.
Methods: All consecutive adult CHD patients with right-sided and left-sided pathologies were identified over a 12 months period. Diagnosis of AF was made on ECG or Holter recording by chart review. LA and RA length and area were obtained from the apical views, and volumes were calculated using 8/3πA2/L where A=area and L=length.
Results: Three hundred and ten patients were identified, 198 with right-sided lesions, 112 with left-sided lesions. Prevalence of atrial fibrillation was 16% in right-sided pathologies versus 7% in left-sided pathologies. In patients with AF and right-sided pathologies, the RA volume was enlarged and greater than the LA volume. In patients with AF and left- sided pathologies, the LA volume was increased and greater than RA volume.
Conclusion: Patterns of atrial dilatation differ according to sidedness of underlying cardiac pathologies. Different initiating mechanisms of AF in patients with right-sided heart lesion should be considered.