Left atrial enlargement in patients with paroxysmal atrial fibrillation.

The present study was designed to examine whether the left atrium is dilated in paroxysmal atrial fibrillation or not. Left atrial dimension (LAD) on M-mode echocardiogram was (1) 23.3 +/- 0.7 mm (mean +/- S.E.) in 24 normal subjects, (2) 30.5 +/- 0.7 mm in 58 patients without atrial fibrillation who had hypertension and/or ischemic heart disease, (3) 35.5 +/- 0.9 mm in 27 patients with paroxysmal atrial fibrillation of whom 23 had non-rheumatic cardiovascular diseases and 4 had idiopathic atrial fibrillation, (4) 40.5 +/- 1.1 mm in 38 patients with persistent atrial fibrillation of whom 30 had nonrheumatic cardiovascular diseases and 8 had idiopathic atrial fibrillation, and (5) 53.3 +/- 2.0 mm in 17 patients with persistent atrial fibrillation who had rheumatic heart disease. LAD showed a stepwise and significant increase from the first to the fifth group. LAD of patients with paroxysmal atrial fibrillation was not related to either the number or duration of paroxysms. These results indicate that the left atrium is slightly dilated in patients with paroxysmal atrial fibrillation.