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PubMed This is a summary of 16 peer-reviewed journal articles Updated
Cardiology

Diagnosis & Understanding Your Reports for FIDC

At a Glance

Familial Isolated Dilated Cardiomyopathy (FIDC) is diagnosed primarily by finding a reduced pumping fraction (LVEF) and an enlarged heart chamber (LVEDD). Key diagnostic tests include echocardiograms, ECGs, and Cardiac MRIs, which help doctors assess heart function and detect scar tissue.

Understanding your medical reports is a vital part of managing Familial Isolated Dilated Cardiomyopathy (FIDC). These documents contain a “report card” of your heart’s current structure and function [1]. While the terminology can be complex, focusing on a few specific measurements will help you track your health and have more productive conversations with your care team [2].

The Two Pillars of Diagnosis

To be diagnosed with FIDC, doctors typically look for two main features on your imaging reports:

  1. Reduced Ejection Fraction (LVEF): Left Ventricular Ejection Fraction (LVEF) is the percentage of blood the heart’s main chamber pumps out with each beat [2]. A normal LVEF is usually between 55% and 70%. In FIDC, this number typically drops below 45–50% [3][4].
  2. Ventricular Dilation (LVEDD): This measures the size of the heart when it is relaxed and full of blood (Left Ventricular End-Diastolic Diameter) [1]. In FIDC, the heart muscle stretches out like an over-expanded balloon. Doctors often “index” this number to your height and weight (Body Surface Area) to ensure the measurement is accurate for your specific body size [5].

Essential Diagnostic Tests

A complete evaluation for FIDC usually involves a suite of tests, each providing a different piece of the puzzle.

  • Echocardiogram (Echo): A specialized ultrasound used to get a quick, non-invasive look at the heart’s size and pumping strength [1].
  • Cardiac MRI (CMR): This is often considered the “gold standard” for FIDC [6]. It provides highly accurate measurements and, crucially, looks for Late Gadolinium Enhancement (LGE)—a fancy term for scar tissue or fibrosis [7][8]. The presence of scarring helps your doctor determine your risk for future heart rhythm issues [9][10].
  • Electrocardiogram (ECG/EKG): This tracks the heart’s electrical activity [11]. Doctors look for “conduction delays,” which are signs that the electrical signal is traveling slowly through the heart muscle. This can sometimes be a clue to specific genetic mutations [12].
  • Coronary Evaluation: Before confirming FIDC, doctors must ensure the heart isn’t weak simply because of “clogged pipes” (coronary artery disease) [2]. This is done using a Coronary Angiogram (a catheter-based look at the arteries) or a Coronary CT Angiogram (a high-tech X-ray) [13][14].

Your Completeness Checklist

When reviewing your records or preparing for an appointment, check your reports for these key items:

Test What to Look For Significance
Echocardiogram LVEF % Measures pumping strength [2]
Echocardiogram LVEDD (mm) Measures heart enlargement [1]
Cardiac MRI LGE or Fibrosis Identifies scar tissue and risk [7]
ECG QRS Duration Checks for electrical “traffic jams” [12]
Genetic Test Pathogenic Variant Identifies the specific genetic “misspelling” [15]
Angiogram “Clean” Arteries Rules out blockages as the cause [14]

If your report shows “LVEF ≤ 35%,” this is a significant marker that doctors use to discuss advanced protective treatments, such as an ICD (Implantable Cardioverter Defibrillator) [3][16]. Knowing these numbers empowers you to understand why your doctors are recommending specific medications or procedures.

To learn exactly how doctors use these numbers to prescribe treatment, read The Modern Standard of Care: Treating FIDC with Confidence.

Common questions in this guide

What does a low LVEF mean on my echocardiogram?
A reduced Left Ventricular Ejection Fraction (LVEF) means your heart's main chamber is pumping out less blood than normal with each beat. In FIDC, this number typically drops below 45 to 50 percent, which helps doctors determine the severity of your condition.
Why do I need a Cardiac MRI if I already had an echocardiogram?
While an echocardiogram provides a good initial look at your heart's size and pumping strength, a Cardiac MRI is the gold standard for FIDC. It offers highly accurate measurements and can detect scar tissue or fibrosis, which helps predict your risk for future heart rhythm issues.
What does Late Gadolinium Enhancement (LGE) mean on my MRI report?
Late Gadolinium Enhancement is a medical term for scar tissue or fibrosis in the heart muscle. Finding LGE on your Cardiac MRI helps your cardiologist assess your risk for abnormal heart rhythms and tailor your treatment plan accordingly.
Why do doctors check my coronary arteries before diagnosing FIDC?
Before confirming a diagnosis of Familial Isolated Dilated Cardiomyopathy, doctors must ensure your weakened heart isn't simply caused by clogged arteries. They perform a coronary angiogram or CT scan to rule out coronary artery disease as the root cause of your symptoms.
What is LVEDD and why is it measured?
Left Ventricular End-Diastolic Diameter (LVEDD) measures the size of your heart's main pumping chamber when it is relaxed and full of blood. In FIDC, this measurement shows if the heart muscle has stretched out and enlarged like a balloon.

Questions to Ask Your Doctor

Curated prompts to bring to your next appointment.

  1. 1.What was my exact Left Ventricular Ejection Fraction (LVEF) on my most recent imaging?
  2. 2.Was any Late Gadolinium Enhancement (LGE) or 'scarring' found on my Cardiac MRI, and where exactly was it located?
  3. 3.How does my Left Ventricular End-Diastolic Diameter (LVEDD) compare to the normal range for my body size?
  4. 4.Do my ECG results show any 'conduction delays,' like a prolonged PR interval or a wide QRS complex?
  5. 5.Since we suspect FIDC, have you ruled out 'clogged pipes' using a coronary angiogram or a CT scan?

Questions For You

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References

References (16)
  1. 1

    Diagnosis and assessment of dilated cardiomyopathy: a guideline protocol from the British Society of Echocardiography.

    Mathew T, Williams L, Navaratnam G, et al.

    Echo research and practice 2017; (4(2)):G1-G13.

    PMID: 28592613
  2. 2

    Proposal for a revised definition of dilated cardiomyopathy, hypokinetic non-dilated cardiomyopathy, and its implications for clinical practice: a position statement of the ESC working group on myocardial and pericardial diseases.

    Pinto YM, Elliott PM, Arbustini E, et al.

    European heart journal 2016; (37(23)):1850-8 doi:10.1093/eurheartj/ehv727.

    PMID: 26792875
  3. 3

    Association of galectin-3 with changes in left ventricular function in recent-onset dilated cardiomyopathy.

    Rieth AJ, Jung C, Gall H, et al.

    Biomarkers : biochemical indicators of exposure, response, and susceptibility to chemicals 2019; (24(7)):652-658 doi:10.1080/1354750X.2019.1642959.

    PMID: 31305163
  4. 4

    Association Between Midwall Late Gadolinium Enhancement and Sudden Cardiac Death in Patients With Dilated Cardiomyopathy and Mild and Moderate Left Ventricular Systolic Dysfunction.

    Halliday BP, Gulati A, Ali A, et al.

    Circulation 2017; (135(22)):2106-2115 doi:10.1161/CIRCULATIONAHA.116.026910.

    PMID: 28351901
  5. 5

    Validation of transpulmonary thermodilution variables in hemodynamically stable patients with heart diseases.

    Hilty MP, Franzen DP, Wyss C, et al.

    Annals of intensive care 2017; (7(1)):86 doi:10.1186/s13613-017-0307-0.

    PMID: 28831765
  6. 6

    Utilization of Cardiac Magnetic Resonance Imaging for Assessing Myocardial Fibrosis in Prognosis Evaluation and Risk Stratification of Patients with Dilated Cardiomyopathy.

    Feng XY, Zheng YC, Yang YX, et al.

    Reviews in cardiovascular medicine 2025; (26(1)):25654 doi:10.31083/RCM25654.

    PMID: 39867184
  7. 7

    Myocardial Fibrosis as a Pathway of Prediction of Ventricular Arrhythmias and Sudden Cardiac Death in Patients With Nonischemic Dilated Cardiomyopathy.

    Centurión OA, Alderete JF, Torales JM, et al.

    Critical pathways in cardiology 2019; (18(2)):89-97 doi:10.1097/HPC.0000000000000171.

    PMID: 31094736
  8. 8

    Prognostic value of late gadolinium enhancement in cardiac MRI of non-ischemic dilated cardiomyopathy patients.

    Behera DR, V K AK, K K NN, et al.

    Indian heart journal 2020; (72(5)):362-368 doi:10.1016/j.ihj.2020.06.011.

    PMID: 33189195
  9. 9

    Distribution of Ventricular Fibrosis Associated With Life-Threatening Ventricular Tachyarrhythmias in Patients With Nonischemic Dilated Cardiomyopathy.

    Chimura M, Kiuchi K, Okajima K, et al.

    Journal of cardiovascular electrophysiology 2015; (26(11)):1239-1246 doi:10.1111/jce.12767.

    PMID: 26223827
  10. 10

    Myocardial scar predicts monomorphic ventricular tachycardia but not polymorphic ventricular tachycardia or ventricular fibrillation in nonischemic dilated cardiomyopathy.

    Piers SR, Everaerts K, van der Geest RJ, et al.

    Heart rhythm 2015; (12(10)):2106-14.

    PMID: 26004942
  11. 11

    Familial dilated cardiomyopathy: A multidisciplinary entity, from basic screening to novel circulating biomarkers.

    de Gonzalo-Calvo D, Quezada M, Campuzano O, et al.

    International journal of cardiology 2017; (228()):870-880 doi:10.1016/j.ijcard.2016.11.045.

    PMID: 27889554
  12. 12

    Emerging concepts in arrhythmogenic dilated cardiomyopathy.

    Zegkos T, Panagiotidis T, Parcharidou D, Efthimiadis G

    Heart failure reviews 2021; (26(5)):1219-1229 doi:10.1007/s10741-020-09933-z.

    PMID: 32056050
  13. 13

    Implementation of coronary computed tomography angiography as nationally recommended first-line test in patients with suspected chronic coronary syndrome: impact on the use of invasive coronary angiography and revascularization.

    Nissen L, Winther S, Schmidt M, et al.

    European heart journal. Cardiovascular Imaging 2020; (21(12)):1353-1362 doi:10.1093/ehjci/jeaa197.

    PMID: 32888290
  14. 14

    Cardiac Computed Tomography Angiography in the Evaluation of Coronary Artery Disease: An Interventional Perspective.

    Widmer RJ, Rosol ZP, Banerjee S, et al.

    Journal of the Society for Cardiovascular Angiography & Interventions 2024; (3(3Part B)):101301 doi:10.1016/j.jscai.2024.101301.

    PMID: 39131218
  15. 15

    Molecular studies in familial dilated cardiomyopathy - A pilot study.

    Mori V, Sawhney JPS, Verma IC, et al.

    International journal of cardiology. Heart & vasculature 2022; (40()):101023 doi:10.1016/j.ijcha.2022.101023.

    PMID: 35463915
  16. 16

    Long-term outcome and predictors of outcome in patients with non-ischemic dilated cardiomyopathy.

    Karatolios K, Holzendorf V, Richter A, et al.

    International journal of cardiology 2016; (220()):608-12.

    PMID: 27390998

This guide is for informational purposes to help you understand FIDC cardiology reports. Always consult your cardiologist or genetic counselor for advice on interpreting your specific test results.

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