Cardiopulmonary MedicineORIGINAL ARTICLE

Estimating ejection fraction and heart failure severity using cardiac apex angles: a multiphase pilot study

Schafer Paladichuk, BS; Graydon Dietrich, BS; Austin Evanovich, BS; Dane Warp, DO; Ronald F. Walser, DPT; Dan Selski, PhD; and Jesse Cone, MD
Notes and Affiliations
Notes and Affiliations

Received: June 19, 2025

Accepted: January 14, 2026

Published: March 5, 2026

  • Schafer Paladichuk, BS, 

    Department of Anatomy,
    472550
    Pacific Northwest University of Health Sciences College of Osteopathic Medicine
    , Yakima, WA, USA

  • Graydon Dietrich, BS, 

    Loma Linda University School of Medicine, Loma Linda, CA, USA

  • Austin Evanovich, BS, 

    Department of Anatomy,
    472550
    Pacific Northwest University of Health Sciences College of Osteopathic Medicine
    , Yakima, WA, USA

  • Dane Warp, DO, 

    Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA

  • Ronald F. Walser, DPT, 

    Department of Anatomy,
    472550
    Pacific Northwest University of Health Sciences College of Osteopathic Medicine
    , Yakima, WA, USA

  • Dan Selski, PhD, 

    Department of Anatomy,
    472550
    Pacific Northwest University of Health Sciences College of Osteopathic Medicine
    , Yakima, WA, USA

  • Jesse Cone, MD, 

    Department of Cardiology, University of Washington, Seattle, WA, USA

Abstract

Context: Heart failure (HF) affects 6.7 million American adults. The gold standard for HF assessment is echocardiography (echo) to determine the ejection fraction (EF). Evaluating the cardiac apex angle may be a possible way to estimate EF; however, there is a lack of investigation into this relationship.

Objectives: This study aimed to evaluate whether a correlation exists between the cardiac apex angle and EF.

Methods: A new, standardized method was developed to measure the cardiac apex angle, with the apex as the vertex, the inferior ray extending from the vertex to the right heart border, and a superior ray extending to the intersection of the left atrial appendage and ventricle. Cadaveric hearts were assessed and patient data from the Medical Information Mart for Intensive Care (MIMIC-IV) database were retrospectively analyzed. Chest X-rays (CXR) provided the cardiac apex angles, and echocardiogram reports contained matched EF values.

Results: In 15 cadaveric hearts, the average apex angle was 47.2°, and the average EF was 48.5 %. Linear regression analysis revealed an R2 value of 0.6543. In the MIMIC-IV cohort of 583 unique patients with matched echocardiograms and CXRs, the average EF was 52.7 %, and the average apex angle was 47.2°, with linear regression analysis revealing an R2 value of 0.7018. This was further broken down by sex and CXR direction.

Conclusions: Access to echo may be limited in resource-constrained settings. Utilizing CXRs to estimate EF offers a practical alternative, potentially enabling early diagnosis and standardized treatment. This approach leverages common imaging modalities to bridge diagnostic gaps and improve HF management.

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