# Qp/Qs – Pulmonary-Systemic Flow Ratio

#### Reference Values

 Qp/Qs Normal 1:1 Left to right shunts >1.0 Right to left shunts <1.0

#### Formulas

$Qp = RVOT \hspace{0.2cm} VTI \times \pi \times (\frac{RVOT}{2})^2$
$Qs = LVOT \hspace{0.2cm} VTI \times \pi \times (\frac{LVOT}{2})^2$
$Qp/Qs \hspace{0.2cm}Ratio = \frac{Qp}{Qs}$

#### Definitions

 Qp Pulmonary flow Qs Systemic flow LVOT Left ventricular outflow tract LVOT VTI Left ventricular outflow tract velocity-time integreal RVOT Right ventricular outflow tract RVOT VTI Right ventricular outflow tract velocity-time integreal Qp/Qs Pulmonary-systemic shunt ratio

#### Reference

 1 Sanders SP, et al. Measurement of systemic and pulmonary blood flow and Qp/Qs ratio using Doppler and two-dimensional echocardiography. Am J. Cardiol, 51:952, 1983. Abstract

#### Disclaimer

We are doing our best to prepare the content of this website. However, Cardiology Connections, Corp cannot warranty the expressions and suggestions of the contents, as well as its accuracy. In addition, to the extent permitted by the law, Cardiology Connections, Corp shall not be responsible for any losses and/or damages due to the usage of the information on our website. Furthermore, the links contained on our website may lead to external sites, which are provided for convenience only. Any information or statements that appeared in these sites are not sponsored, endorsed, or otherwise approved by Cardiology Connections, Corp. For these external sites, Cardiology Connections, Corp cannot be held liable for the availability of, or the content located on or through it. Plus, any losses or damages occurred from using these contents or the internet generally.

Developer & Illustrator: Sirikarn Napan, MD, FACC