An association of atrial septal aneurysm (ASA) with cardiac arrhythmias has
been described, and it has been suggested that undulating movements of the
aneurysm initiate these arrhythmias, thereby causing arterial embolism. In
this prospective study, all available electrocardiograms were reviewed and
Hotter monitoring was performed in 50 consecutive patients with echocardio
graphic diagnosis of ASA in order to assess the relationship between the oc
currence of arrhythmias, morphologic characteristics of ASA and arterial em
bolism, Significant arrhythmias were identified in 26 (52%) patients (supra
ventricular n = 15, ventricular n = 6, both n= 5), Patients with arrhythmia
s were older (65 +/- 12 vs. 54 +/- 13 years, p = 0.005), frequently had pal
pitations (21/26 vs. 1/24, p < 0.0001) and an abnormal resting electrocardi
ogram (18/26 vs. 5/24, p < 0.001). By echocardiography, patients with arrhy
thmias had a larger left atrial (42.8 +/- 7.4 vs. 35.3 +/- 4.6 mm, p < 0.00
01) and left ventricular enddiastolic diameter (53.8 +/- 5.6 vs. 49.7 +/- 4
.1, p < 0.01) and a higher prevalence of associated mitral valve prolapse (
12/26 vs, 4/24, p = 0.05). Potential cardiovascular causes for arrhythmia o
ther than ASA were present in the great majority of patients with documente
d arrhythmias (24/26 vs. 7/24, p < 0.0001). The base diameter of ASA was la
rger in patients with arrhythmias (25.5 +/- 6.2 vs. 21.4 +/- 3.4, p < 0.01)
and correlated with a larger left atrial diameter (r = 0.72, p < 0.0001),
Concerning the mobility of ASA (maximal protrusion or phasic excursion), th
ere was no significant difference between the two patient groups. Arterial
embolism, however, predominantly occurred in ASA patients without arrhythmi
as (16/24 vs. 9/26, p < 0.05). In conclusion, the majority of patients with
ASA and arrhythmias has underlying structural heart disease other than ASA
which may be responsible for the arrhythmias observed. Arrhythmias in asso
ciation with ASA do not play a major role as a mechanism for arterial embol
ism.