Predicting Intermittent Atrial Fibrillation in Outpatient Clinics

Palpitations are the most common complaint in cardiology outpatient clinics. These palpitations may be derived from paroxysmal atrial fibrillation (AF) and can be easily overlooked. It is unclear whether inter-atrial conduction time (ICT) may predict the paroxysmal AF in out-patients that present with palpitations. We evaluated the ability of the ICT to predict paroxysmal AF in these patients.

The study group consisted of 199 patients (110 female). All patients underwent 24-hour Holter electrocardiogram (ECG) monitoring (total of 327 Holter ECG monitorings, mean: 1.64 times per patient). Brief episodes of AF were documented in 35 patients (20 female, Group 1). The remaining patients without AF were designated as Group 2 (90 female). All patients underwent routine transthoracic echocardiographic examination. ICT was also measured by echocardiography.

The mean age in Group 1 was greater than in Group 2 (63.02±14 vs. 51.27±16 years, p<0.001). The left atrium was larger in Group 1 than in Group 2 (39.7±3.4 vs. 37.29±4.3 mm, p<0.001). The other echocardiographic variables were comparable between the two groups. The mean ICT was significantly higher in Group 1 than in Group 2 (138±14 vs. 114±12 msn, p<0.001). The ICT of 127 ms was predictive for AF with a sensitivity of 86% and specificity of 87% (p<0.001).

Our findings show that ICT was prolonged in patients with palpitations who developed a brief episode of AF in Holter ECG monitoring. ICT prolongation may be used to identify patients with palpitation that are at risk of an AF episode. Holter ECG monitoring should be repeated to detect AF episodes in patients with prolonged ICT.