BACKGROUND:There are several risk factors for the initiation of paroxysmal atrial fibrillation (PAF) and the underlying mechanisms are multifactorial. Our study aims to explore the echocardiographic parameters that can identify in patients with PAF compared to normal subjects. METHODS:Eighty consecutive patients who were with PAF detected by 24-h Holter monitoring (HM) were assigned in our study. The control group (n = 80) consisted individuals with no PAF on HM. Indication for HM was palpitations at rest. All patients underwent routine echocardiographic evaluation. Patients with aortic and mitral stenosis, hyperthyroidism, and hypothyroidism were excluded from the study. Comprehensive clinical data were collected. RESULTS:Mean age of the patients with PAF was 63 +/- 11 years and of those 42% were male subjects. There was no difference in the prevalence of hypertension in both groups. Mean left ventricular ejection fraction (LVEF) was 57 +/- 15% in PAF group and 64 +/- 2% in control subjects (p < 0.001). Mean values of left atrial (LA) diameter for PAF and control groups were 3.7 +/- 0.6 cm vs. 3.1 +/- 0.4 cm (p < 0.001), respectively. Patients with PAF had more severe valve insufficiency, higher values of mean pulmonary artery systolic pressures (PAP) (29 +/- 10 mmHg vs. 25 +/- 2 mmHg, respectively; p = 0.001) and deteriorated MV inflow velocities (E:A ratio 0.9 +/- 0.4 vs. 1.1 +/- 0.3, respectively; p = 0.008) when compared to control group. In multivariate logistic regression analysis, LA diameter predicted the development of PAF after adjusted for age and gender. CONCLUSION:Our results indicate that LA diameter predicts the development of PAF.