Atrial septal defect echocardiography modalities


 * Associate Editor(s)-In-Chief: Priyamvada Singh, M.B.B.S. [mailto:psingh@perfuse.org], ; Assistant Editor(s)-In-Chief: Kristin Feeney, B.S. [mailto:kfeeney@perfuse.org]

For a full discussion on the usage of echocardiography for atrial septal defect diagnosis click here.

Overview
Echocardiography is the preferred diagnostic tool in the evaluation of an atrial septal defect. A range of techniques may be employed to definitively image and diagnose the nature of an atrial septal defect. These include modalities such as: M-mode, trans-thoracic, trans-esophageal, contrast, and Doppler.

Echocardiography Techniques for ASD
A range of echocardiography techniques can be used to visualize and diagnose a suspected atrial septal defect. Each technique offers additional imaging information to support an atrial septal defect diagnosis.

M-mode

 * Effective modality for imaging moderate to large ostium secundum atrial septal defects
 * Provides imaging of:
 * Right ventricular enlargement
 * Paradoxical motion involving the interventricular septum

Disadvantages

 * M-mode modality can appear indicative of right ventricular overload. It is not substantial enough alone to make a full diagnosis of a suspected atrial septal defect.

Doppler

 * Used to demonstrate left to right flow.
 * Effective modality for:
 * Confirmation of a suspected atrial septal defect
 * Estimation of the defect size
 * Determination of the universal direction of flow across the septum
 * Determination of the usage of percutaneous closure and surgical therapies
 * Determination of high velocity flow, useful in patients with restrictive defects, obstructed pulmonary venous return and/or left atrial hypertension

Disadvantages

 * May show false positive shunting as caval flow and incorrectly set gain may appear as left to right flow.
 * Coloring across the interatrial septum can distort the perception of the shunt flow
 * Not effective in determination of sinus venosus defects

==ACC / AHA Guidelines - Evaluation of the Unoperated Patient (DO NOT EDIT) == {{cquote|

Class I
1) ASD should be diagnosed by imaging techniques with demonstration of shunting across the defect and evidence of RV volume overload and any associated anomalies. (Level of Evidence: C) }}