Paroxysmal atrial fibrillation (PAF) carries an equally high annual stroke rate as chronic atrial fibrillation (AF). Furthermore, the frequency and duration of PAF are thought to be associated with stroke risk. In this pilot study, a trans-telephonic electrocardiograph (TTE) monitoring system was used to detect asymptomatic PAF and to study the relationship between ischemic stroke and the frequency of PAF. Between December 2004 and April 2006, 70 patients enrolled in the TTE monitoring program. Patients either transmitted electrocardiograms (ECGs) daily or upon experiencing cardiac symptoms. Of the 70 patients included, 25 were diagnosed with PAF. In total, 11% (855/7,768) of the recordings were diagnosed as PAF, yet less than 2% of total calls collected and less than 17% of all the calls with PAF were associated with obvious symptoms. Four patients developed five ischemic strokes resulting in a calculated annual stroke rate of 0.56%. Patients with stroke had more episodes of AF (56.5±106.3 versus 6.7±85.9, p=0.685) and symptomatic AF episodes (9.8±17.5 versus 4.9±8.1, p=0.381) than the patients who did not have a stroke, but the differences were not statistically significant because of the low numbers of patients and episodes. Most PAF episodes were asymptomatic, and the TTE system could easily detect these episodes. Furthermore, these four patients tended to have more episodes of PAF and more symptomatic attacks of PAF than patients who did not have a stroke.