Atrial septal defect echocardiography modalities

{Atrial septal defect}} Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-In-Chief: Priyamvada Singh, M.B.B.S. [2], Cafer Zorkun, M.D., Ph.D. [3]; Assistant Editor(s)-In-Chief: Kristin Feeney, B.S. [4]

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