[Relationship between left atrial size and paroxysmal atrial fibrillation in acute ischemic stroke]

We investigated the relationship between parosysmal atrial fibrillation (pAF) and left atrial (LA) size in patients with acute ischemic stroke. Between June 2006 and April 2008, we retrospectively enrolled 292 patients with acute ischemic stroke within 24 hours of onset, who measured LA size by transthoracic echocardiography. The patients were classified according to the presence or absence of chronic AF on admission (cAF and normal sinus rhythm (NSR) group). The NSR group was subdivided based on the pAF (pAF and non-AF group). We compared LA size among each groups. Furthermore in the NSR group, the factors associated with pAF were investigated by multivariate logistic regression analysis. Among the enrolled patients, cAF (cAF group) had 77 (26.4%), pAF (pAF group) had 32 (11.0%) and non-AF group was 183 (62.7%). The median of LA size of the cAF was highest (4.7 cm), followed by the pAF group (4.1 cm) and the non-AF group (3.5 cm) (p<0.001). Median age (72.0 for the non-AF group vs. 74.5 years for the pAF group, p<0.001), NIHSS score on admission (3.0 vs. 12.5, p<0.001), D-dimer (0.6 vs. 2.1 microg/ml, p=0.003), LA size (3.5 vs. 4.1 cm, p<0.001) were higher in the pAF group than in the non-AF group. The optimal cut-off value, sensitivity and specificity of LA size to distinguish pAF from non-AF were 3.8 cm, 68.6% and 73.8%, respectively. Multivariate logistic regression analysis demonstrated that a NIHSS score of > or =8 (odds ratio [OR], 4.399; 95% confidence interval [CI], 1.701 to 11.378, p=0.002), LA size of > or =3.8 cm (OR, 8.882; 95% CI, 3.238 to 24.268, p<0.001) and mitral valvular disease (OR, 4.677; 95% CI, 1.720 to 12.720, p=0.003) were independent factors associated with pAF. We should consider the presence of pAF when LA size is over 3.8 cm in acute ischemic stroke patients with sinus rhythm.