Atrial septal aneurysm and cardiac arrhythmias.

Atrial septal aneurysm has been associated with thromboembolic events, interatrial shunting, mitral valve prolapse, and systolic click. An association between atrial septal aneurysm and cardiac arrhythmias has been also described. Twenty patients with atrial septal aneurysm and 19 control subjects performed 24-h Holter monitoring. Frequent (> 10/h) atrial premature beats were observed in seven patients vs. none of the controls (P = 0.008). The mean number of episodes of supraventricular tachycardia and the prevalence of ventricular tachycardia were also higher in the atrial septal aneurysm group (P = 0.044 and P = 0.046, respectively). Left atrial enlargement, mitral valve prolapse and left ventricular hypertrophy were more frequent than in the normal subjects. In conclusion, atrial and ventricular 'complex' arrhythmias occurred more frequently in patients with atrial septal aneurysm than in normal subjects. Further studies in patients with atrial septal aneurysm without other associated echocardiographic abnormalities need to be done to ascertain a potential arrhythmogenicity of this condition.