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PubMed This is a summary of 19 peer-reviewed journal articles Updated
Cardiology

Decoding Your Imaging: How Doctors "See" the Hole

At a Glance

Cardiac imaging like TTE, TEE, and bubble studies are used to detect interatrial communications such as PFOs and ASDs. Key measurements on your report, including defect size, rim measurements, shunt direction, and the Qp:Qs ratio, help your cardiologist determine if the hole needs to be closed.

Reading a cardiac imaging report can feel like trying to translate a foreign language. However, these documents contain the “measurements” that determine whether you need a procedure, a prescription, or simply a follow-up appointment [1]. Understanding a few key terms can help you move from being a passenger to a partner in your care.

The Tool Kit: TTE vs. TEE

Doctors use two main types of ultrasound (echocardiograms) to look at the heart’s walls.

  • TTE (Transthoracic Echocardiogram): This is the standard “jelly on the chest” ultrasound [2]. It is non-invasive and excellent for a general look at heart size and function, but it may miss very small holes [2][3].
  • TEE (Transesophageal Echocardiogram): This is the “gold standard” for detail [4]. A small probe is passed down the esophagus (swallow tube) while you are sedated [2]. Because the esophagus sits directly behind the heart, the pictures are much clearer and can show the exact shape and “rims” of a hole [4][5].

The Bubble Study and the Valsalva Maneuver

A bubble study is the most common way to “see” a Patent Foramen Ovale (PFO) [3]. A salt-water solution (saline) is shaken to create tiny, harmless microbubbles and injected into a vein [3].

  1. Normally, these bubbles go to the right atrium and are filtered out by the lungs.
  2. If bubbles appear on the left side of the heart within 3 to 6 beats, it proves there is a connection (shunt) between the chambers [6][7].

The Valsalva maneuver (bearing down as if lifting something heavy) is crucial during this test [8]. It momentarily increases pressure on the right side of the heart. For a PFO, this maneuver is necessary because the flap usually stays closed; the sudden pressure change “pushes” the PFO flap open transiently so the bubbles can cross [9][10]. Without a proper Valsalva, a PFO can easily be missed [8].

Shunt Directions: Why They Matter

Your report will likely mention the “direction” of the blood flow.

  • Left-to-Right Shunt: Common in ASDs. Higher-pressure oxygenated blood from the left side leaks into the right side [11]. This causes “volume overload,” meaning the right side of the heart has to pump more blood than it was designed for [12].
  • Right-to-Left Shunt: Common in PFOs. Lower-pressure deoxygenated blood (which might contain a tiny clot) crosses to the left side [13]. In a PFO, this right-to-left shunt is usually transient, occurring only when coughing, bearing down, or straining. This is the mechanism behind a paradoxical embolism, where a clot from a leg vein “paradoxically” ends up in the brain instead of the lungs [14][7].

Imaging Report Completeness Checklist

When you receive your report, look for these specific sections to ensure your care team has the full picture:

Finding Why it Matters
Defect Size Measured in millimeters (mm). Larger holes are more likely to need closure [15].
Rim Measurements For a catheter plug to stay in place, there must be enough “shelf” or tissue (usually >5mm) around the hole to grip [15][16].
Right Ventricle (RV) Size If the RV is “dilated” (enlarged), it is a sign that the shunt is causing physical strain on the heart [17].
Atrial Septal Aneurysm A “floppy” or bulging wall between the chambers. When present with a PFO, it may increase the risk of stroke [4][18].
Qp:Qs Ratio A mathematical calculation of the shunt size. A ratio over 1.5:1 often triggers a recommendation for repair [19].

Return to the Home Page

Common questions in this guide

What is the difference between a TTE and a TEE for diagnosing a hole in the heart?
A TTE is a standard, non-invasive chest ultrasound that provides a general look at the heart. A TEE involves passing a small probe down the esophagus while you are sedated, offering much clearer pictures of the heart's walls and hole dimensions.
Why is the Valsalva maneuver important during a bubble study?
Bearing down during a bubble study temporarily increases pressure on the right side of the heart. This pressure is necessary to push open a patent foramen ovale (PFO) flap so the bubbles can cross, making the hole visible on the ultrasound.
What does a right-to-left shunt mean on my echocardiogram?
A right-to-left shunt means blood is crossing from the right side of the heart to the left side. This is common in a PFO and can potentially allow a small blood clot to bypass the lungs and reach the brain.
What is a Qp:Qs ratio on a cardiac imaging report?
The Qp:Qs ratio is a mathematical calculation that measures the size and impact of the blood shunt. A ratio over 1.5 to 1 usually indicates the right side of the heart is working too hard, and a closure procedure might be recommended.
Why do doctors measure the rims around a heart hole?
Measuring the rims or edges of the hole ensures there is enough tissue to securely grip and hold a catheter closure device in place. Typically, doctors look for a tissue rim of at least 5 millimeters in all directions.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.Was the 'bubble study' performed with a Valsalva maneuver, and was the maneuver considered effective?
  2. 2.How many bubbles crossed to the left side, and what 'grade' of shunt does that represent?
  3. 3.Are the 'rims' (the edges of the hole) at least 5mm wide in all directions?
  4. 4.Does my report show any 'atrial septal aneurysm' or other high-risk features?
  5. 5.What was my 'Qp:Qs' ratio, and what does that tell us about the extra work my heart is doing?

Questions For You

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References

References (19)
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    Interatrial shunts: technical approaches to percutaneous closure.

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    PMID: 30246569
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    Aortic dissection and multimodality imaging.

    Paulraj S, Ashok Kumar P, Uprety A, Chaudhuri D

    Echocardiography (Mount Kisco, N.Y.) 2020; (37(9)):1485-1487 doi:10.1111/echo.14820.

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    Comparative diagnostic accuracy of transcranial Doppler and contrast-enhanced transthoracic echocardiography for the diagnosis of patent foramen ovale and atrial septal defect.

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    Morphometric Features of Patent Foramen Ovale as a Risk Factor of Cerebrovascular Accidents: A Systematic Review and Meta-Analysis.

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    PMID: 32097931
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    Echocardiographic diagnosis of right-to-left shunt using transoesophageal and transthoracic echocardiography.

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    PMID: 32763965
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    Differentiation between patent foramen ovale and pulmonary arteriovenous malformations via simultaneous contrast transthoracic echocardiography and transcranial doppler.

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    Contrast-enhanced transthoracic echocardiography applied in evaluation of pulmonary right-to-left shunt: A preliminary study.

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    Provocative maneuvers to improve patent foramen ovale detection: A brief review of the literature.

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    Apical Left Ventricular Pseudoaneurysm With Left-to-Right Shunt: A Rare Mechanical Complication of Myocardial Infarction Involving Both Ventricles.

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    Think beyond right bundle branch block in atrial septal defect.

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    Cor Triatriatum Dexter: Contrast Echocardiography Is Key to the Diagnosis of a Rare but Treatable Cause of Neonatal Persistent Cyanosis.

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This page explains cardiac imaging terminology for educational purposes only and does not replace professional medical advice. Always review your echocardiogram report with your cardiologist to understand your specific diagnosis and treatment needs.

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