Atrial septal defect echocardiography modalities
|
Atrial Septal Defect Microchapters | |
|
Treatment | |
|---|---|
|
Surgery | |
|
| |
|
Special Scenarios | |
|
Case Studies | |
|
Atrial septal defect echocardiography modalities On the Web | |
|
American Roentgen Ray Society Images of Atrial septal defect echocardiography modalities | |
|
Atrial septal defect echocardiography modalities in the news | |
|
Risk calculators and risk factors for Atrial septal defect echocardiography modalities | |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editors-In-Chief: Priyamvada Singh, M.B.B.S. [2], Cafer Zorkun, M.D., Ph.D. [3]; Assistant Editor-In-Chief: Kristin Feeney, B.S. [4]
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: a sub-costal four chamber view, doppler echocardiography, contrast echocardiogrpahy, and transesophageal echocardiography.
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
- Note: imaging in M-mode modality can be indicative of right ventricular overload. It is not substantial enough alone to make a full diagnosis of a suspected atrial septal defect.
Trans-thoracic echocardiography
- Effective two-dimensional modality for visualizing an ostium secundum atrial septal defect.
- Types:
- Apical four chamber view
- Subcoastal four chamber view
- Provides imaging of:
- Right ventricular enlargement
- Paradoxical motion involving the ventricular septum
- Right atrium enlargement
Advantages
- Determines which type of defect exists.
- Necessary to evaluate for anomalous pulmonary veins.
- Evaluates for an atrial septal aneurysm.
Disadvantages
- Apical four chamber view involves a parallel angle of the echocardiographic beams onto the atrial septum causing artifact in the echo
- Subcostal four chamber view can be ineffective in overweight/obese patients.
- Size of the defect seen in a TTE does not parallel the measurement of shunt flow from cardiac catheterization.
Sensitivity
- One study found that subcostal approach could successfully visualize the majority of ostium primum and ostium secundum atrial septal defects.[1]
- Visualization of sinus venosus atrial septal defect is less successful, less than 50% of the cases were properly imaged.[1]
Trans-esophageal echocardiography (TEE)
Contrast echocardiography
- Used to determine the presence of intercardiac shunting often seen in the apical four chamber view
- Agitated saline is commonly used as the contrast material.
- Injected into a peripheral vein during echocardiography, small air bubbles can be seen on the imaging.
- It may be possible to see bubbles travel across an atrial septal defect either at rest or during a cough.
- Bubbles will only flow from right atrium to left atrium if the RA pressure is greater than LA
Common Findings
- A right-to-left interatrial shunt can be seen:
- When an atrial septal defect with accompanying pulmonary hypertension, resulting in a left-to-right reversal.
- Any time a patent foramen ovale defect is present.
- When an uncomplicated atrial septal defect has an imbalance in right-sided pressure, such as from coughing or the Valsalva maneuver.
- When an uncomplicated atrial septal defect has a momentary onset of left ventricular contraction.
Sensitivity
- Not recommended for:
- Left-to-right interatrial shunt diagnosis
- Pregnant patients
- Patients with severe pulmonary hypertension
Disadvantages
- False positives in the setting of a pulmonary arteriovenous malformation.
- Difficulty in quantifying the size of the shunt
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
References
- ↑ 1.0 1.1 Shub C, Dimopoulos IN, Seward JB, Callahan JA, Tancredi RG, Schattenberg TT; et al. (1983). "Sensitivity of two-dimensional echocardiography in the direct visualization of atrial septal defect utilizing the subcostal approach: experience with 154 patients". J Am Coll Cardiol. 2 (1): 127–35. PMID 6853907.