title: Use of saline contrast echo timing to distinguish intracardiac and extracardiac shunts: failure of the 3- to 5-beat rule.
abstract: Patent foramen ovale (PFO) is thought to be associated with cryptogenic stroke and migraine headache. Saline contrast echocardiography (SCE) is the gold standard for identifying the presence of right-to-left shunt, whether from PFO or pulmonary arteriovenous malformation (PAVM). The timing of left heart contrast entry during SCE is used to distinguish a PFO from a PAVM, a method that is not as specific as previously thought. In this report, we describe a patient with a SCE demonstrating the early appearance of left heart bubbles during good effort Valsalva injections that is ultimately proven to be due to a PAVM. The case illustrates the limited specificity of left heart contrast timing during SCE as the sole criteria for differentiating intracardiac and extracardiac shunts.
authors.affiliation: Department of Medicine, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Freeman
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Woods
mesh_terms: D000328:Adult; D001165:Arteriovenous Malformations / Q000175:diagnosis*; D003287:Contrast Media; D003937:Diagnosis, Differential; D004452:Echocardiography / Q000379:methods* / Q000639:trends; D054092:Foramen Ovale, Patent / Q000175:diagnosis; D006344:Heart Septal Defects, Atrial / Q000175:diagnosis; D006801:Humans; D008297:Male; D011652:Pulmonary Circulation; D012965:Sodium Chloride; D014636:Valsalva Maneuver
chemical_list: D003287:Contrast Media; D012965:Sodium Chloride