Lower patent foramen ovale detection with transthoracic echocardiography in atrial fibrillation

Background: Patent foramina ovale (PFO) are small defects within the atrial septum that may play a role in paradoxical embolism, stroke and migraines. The relationship between PFO and atrial fibrillation (AF) has not been formally studied. We prospectively studied patients with a history of AF, versus those without (controls), in order to compare PFO prevalence among them. Methods: Sixty-one patients with AF and forty-one controls completed the study, all undergoing transthoracic echocardiography using agitated saline microbubbles and a Valsalva maneuver. Results: In the control group, 12/41 participants (29.2%) had PFOs compared to 5/61 (8.2%) in the AF group (P < 0.01). PFO positive patients within the entire study population demonstrated greater leftward inter-atrial septal shifting (82% vs 49%, P < 0.05). There was also reduced leftward inter-atrial septal shift observed within the AF group compared to controls (32/61 (52%) vs 31/41 (76%), P < 0.05). Conclusion: This study is the first to demonstrate an apparent lower rate of PFO in patients with AF, using bubble contrast echocardiography.