Diagnostic Tests and Understanding Your Results

To evaluate a diagnosis of Tropical Endomyocardial Fibrosis (EMF), doctors use a combination of specialized imaging and blood tests. Because the condition changes the physical structure of the heart, seeing the “map” of these changes is a very important part of your diagnostic journey ^[1][2]. There is no single noninvasive test that confirms every case, so your team will integrate your history with these findings.

The First Step: Transthoracic Echocardiogram (TTE)

A Transthoracic Echocardiogram is an ultrasound of the heart and is the first-line tool for evaluating EMF ^[1]. It is safe, non-invasive, and highly effective at spotting the classic signs of the disease.

When performing this scan, doctors often use the Mocumbi criteria, a specific checklist of features that point toward EMF ^[3]. They are looking for:

• Apical Obliteration: This occurs when the tip (apex) of the heart’s lower chambers appears “filled in” with thick tissue instead of being an open space for blood ^[2].
• Atrial Enlargement: Because the lower chambers are stiff, the upper chambers (atria) must work harder and often become very large ^[4].
• Valve Regurgitation: The scar tissue can pull on the heart’s valves, causing them to leak (regurgitation), which doctors can see and measure ^[5].
• Restrictive Flow: The “filling pattern” of the heart is analyzed to see how much the stiffness is resisting blood flow ^[4].

An Important Complementary Test: Cardiac MRI (CMR)

While an ultrasound is excellent for screening, a Cardiac MRI provides an even more detailed look at the heart’s tissues ^[6]. It is especially helpful for distinguishing EMF from other conditions that might look similar, though its use depends on your kidney function and whether you have implanted devices.

One of the famous findings on a Cardiac MRI for EMF is the “Double V” sign ^[1]. This pattern appears on a specific type of image called Late Gadolinium Enhancement (LGE) and sometimes shows three distinct layers at the tip of the heart:

1. Healthy Heart Muscle: The outer layer of normal myocardium.
2. Scar Tissue: A middle layer of thickened, bright-white scar (fibrosis) ^[7].
3. Blood Clot: An inner layer of dark, non-enhancing thrombus (clot) ^[8].

Importantly, this exact pattern is not present in every patient, and a clot is not obligatory. Beyond just making the diagnosis, the MRI allows doctors to qualitatively or quantitatively assess how much of your heart has been affected by scar tissue. The total “burden” of this fibrosis can be an important predictor of your long-term health, though calculating an exact percentage is not universally standardized ^[1].

Laboratory and Invasive Tests

In addition to pictures of your heart, your team will use blood tests to look for triggers or complications.

• Eosinophil Count: Doctors check for eosinophilia—a high level of white blood cells often linked to allergies or parasites ^[9]. While common in early EMF, these levels may return to normal in later stages ^[10].
• Parasite Screening: Depending on where you have lived, doctors may test for parasites like Schistosoma or Strongyloides using stool samples or blood antibody tests ^[11][12].
• Endomyocardial Biopsy: This is a procedure where a tiny piece of heart tissue is removed for study. While less common when MRI is clear, it remains important when doctors suspect an active eosinophilic myocarditis or other infiltrative diseases ^[3]. It carries some risks and can sometimes miss the diseased area because EMF is “patchy” ^[13][14].

Completeness Checklist

When you receive your imaging reports, you can use this checklist to ensure the most critical information has been captured. A complete report should clearly state:

• [ ] Ventricles Involved: Is it the right side, the left side, or both? What is the size and systolic function (e.g., ejection fraction) of both? ^[4]
• [ ] Apical Status: Is the tip of the heart “obliterated” or “filled in”? ^[2]
• [ ] Thrombus Presence: Is there a visible blood clot inside the heart chambers? ^[8]
• [ ] Valve Function: What is the severity (mild, moderate, severe) of the leaking mitral or tricuspid valves? ^[5]
• [ ] Restrictive Physiology: Are filling pressures, pulmonary pressure, and inferior vena cava size measured?
• [ ] Fibrosis Extent: Does the report describe the “burden” or distribution of scar tissue seen on MRI? ^[1]
• [ ] Atrial Size: Are the upper chambers of the heart enlarged? ^[2]