Prognostic Significance of Left Atrial Size in the Recurrence of Atrial Fibrillation

Atrial fibrillation (AF) is associated with significant morbidity and recurrence despite rhythm control strategies. Identifying reliable predictors of AF recurrence is essential for optimizing patient management.

The aim of this study was to evaluate the predictive value of left atrial (LA) diameter for AF recurrence at six and 12 months following rhythm control interventions.

This prospective observational study included 66 patients with documented AF who underwent rhythm control interventions, including electrical or pharmacological cardioversion. LA diameter was measured by transthoracic echocardiography in the parasternal long-axis view at end-systole, using a standardized protocol by a single blinded operator. LA volume and indexed measurements were not consistently available and were excluded. The primary endpoint was AF recurrence at six and 12 months. AF recurrence was defined as any documented AF episode lasting >30 seconds, confirmed by 12-lead ECG during scheduled visits or symptom-driven ECG recordings. Follow-up was conducted at six and 12 months. Two patients were lost to follow-up.

The study included 66 patients (71.2% men) with a mean age of 65.4 ± 13.7 years. Hypertension (74.2%) and dyslipidemia (54.5%) were the most prevalent comorbidities, while 28.8% were smokers. Mean left ventricular ejection fraction was 52.3 ± 10.5%, with 77.3% of patients having preserved systolic function (LVEF ≥ 50%). Mean left atrial diameter was 43.5 ± 7.2 mm; 31.8% had LA diameter <40 mm, and 12.1% >50 mm. Rhythm control was achieved using electrical cardioversion or antiarrhythmic drugs, with palpitations being the most common presenting symptom. AF recurrence occurred in 51.6% of patients at six months and 50.8% at 12 months. Background pharmacotherapy remained stable during follow-up. LA size >42.5 was significantly associated with having an AF episode at six (OR=7.55; 95%CI: 2.22 - 25.66; p=0.001) and 12 months (OR=41.97; 95%CI: 7.37 - 239.07; p<0.001), after adjusting simultaneously for age, gender, smoking, alcohol, and number of comorbidities. Also, patients who smoked had a significantly greater probability of having an AF episode at 12 months (OR=12.9; 95%CI: 1.70 - 97.75; p=0.001). All possible interactions were tested, but no significant results emerged. The change in AF type distribution (from paroxysmal to persistent) between consecutive timepoints was not significant (p>0.05).

LA diameter >42.5 mm is a simple, non-invasive, and powerful predictor of AF recurrence after rhythm control. Its routine assessment may enhance early risk stratification and guide individualized therapeutic strategies in patients with AF.