Royal Brompton Hospital, London, UK
Correspondence to: Hutan Ashrafian, MBBS, Department of Paediatric Cardiothoracic Surgery, Royal Brompton Hospital, Sydney St, London SW3 6NP, UK; e-mail: email@example.com
I read with interest the piece by Zanchetta et al (August 2005)1 regarding right-to-left shunting through a patent foramen ovale (PFO). Although the authors proposed a hypothesis for inferior caval-to-PFO streaming, they did not propose or address the mechanism for the well-described preferential superior vena caval (SVC) to right atrioventricular valve blood flow.
This dual preferential streaming within the right atrium was initially observed in the 1930s2 and is not only significant in right-to-left shunting but also performs a fundamental role in fetal circulation and development. Both streams are mutually important as disordered blood flow from one stream could interfere with the blood route of the other; for example, misdirected blood from the SVC arriving at the inferior vena cava (IVC) or the IVC-PFO tract would interfere and hinder the blood flow of the right-to-left shunt.
The blood stream from the SVC has been imaged by magnetic resonance velocity mapping and demonstrates that the stream flows anteriorly over the convex muscular internal surface of the anterior right atrial wall directed to the right atrioventricular valve.3Such a stream of flow was first noted in 1910 by Romanian aerodynamics visionary Henri Marie Coanda (1886 to 1972), for whom the effect is eponymously named,4 stating that a fluid stream has a natural tendency to follow the shape of a body as it flows past it. Without the characteristic morphology of the right atrial muscular anterior wall therefore, IVC-to-PFO flow could be interrupted by an SVC blood stream, opposing the right-to-left shunt and resulting in disordered and suboptimal fetal oxygenation. The Coanda effect therefore contributes to the unique mechanism by which the right atrium keeps these two streams separate.
The author has no conflict of interest to disclose.
Become a CHEST member and receive a FREE subscription as a benefit of membership.
Individuals can purchase this article on ScienceDirect.
Individuals can purchase a subscription to the journal.
Individuals can purchase a subscription to the journal or buy individual articles.
Learn more about membership or Purchase a Full Subscription.
Institutional access is now available through ScienceDirect and can be purchased at myelsevier.com.
Some tools below are only available to our subscribers or users with an online account.
Download citation file:
Web of Science® Times Cited: 1
Customize your page view by dragging & repositioning the boxes below.
Enter your username and email address. We'll send you a reminder to the email address on record.
Athens and Shibboleth are access management services that provide single sign-on to protected resources. They replace the multiple user names and passwords necessary to access subscription-based content with a single user name and password that can be entered once per session. It operates independently of a user's location or IP address. If your institution uses Athens or Shibboleth authentication, please contact your site administrator to receive your user name and password.