Previous studies during cardiac catheterization or postmortem examination1 show that a small but patent foramen ovale (PFO) is present in 10 to 35% of patients. More recent reports using contrast echocardiography have demonstrated right-to-left atrial shunting in 5% of healthy volunteers during normal breathing and in 18% during the Valsalva maneuver2; such right-to-left atrial shunting has been detected in 27 to 40% of patients with known or suspected PFO during normal breathing and in 54 to 60% during Valsalva.3,4 With contrast echocardiography, therefore, right-to-left atrial shunting appears to occur often in patients without obvious congenital heart disease,2-4 especially during a maneuver (such as Valsalva) designed to induce a transient increase in right atrial pressure higher than that in the left atrium. In none of these studies, however, has the reliability of contrast echocardiography been compared with more established techniques of detecting intracardiac shunting, such as indocyanine green. No previously published report has used indocyanine green to assess the overall incidence of right-to-left atrial shunting in patients without obvious congenital heart disease. The present study was performed for this purpose.
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine