predicted heart mass calculator - Aaron Graves, PhDude Replica

Calculate Predicted Heart Mass (PHM)

Use this tool to estimate predicted heart mass based on age, sex, height, and weight.

Sex

Age (years)

Height (cm)

Weight (kg)

Optional: Comparison heart mass (g)

Formula used (commonly cited PHM model):
Predicted Heart Mass = Predicted LV Mass + Predicted RV Mass

Predicted LV Mass = A × Height^0.54 × Weight^0.61
Predicted RV Mass = B × Age^-0.32 × Height^1.135 × Weight^0.315

Male coefficients: A = 8.25, B = 11.25
Female coefficients: A = 6.82, B = 10.59

Height is entered in cm and internally converted to meters.

What is predicted heart mass?

Predicted heart mass (PHM) is a mathematical estimate of the expected total heart mass for a person with a given age, sex, height, and weight. It is often discussed in cardiology and heart transplantation as a sizing aid. Instead of relying on one variable (like body weight alone), PHM combines multiple inputs to better approximate biological heart size.

In practical terms, this can support donor-recipient size matching conversations, research screening workflows, and educational understanding of how body size relates to cardiac anatomy.

How this calculator works

Inputs

Sex: selects coefficient values used by the published equations.
Age: included in the right ventricular component.
Height and Weight: key body-size variables used in both components.

Outputs

Predicted LV Mass (g): estimated left ventricular mass.
Predicted RV Mass (g): estimated right ventricular mass.
Total Predicted Heart Mass (g): LV + RV.
Optional mismatch %: if you provide a comparison mass, the tool shows difference versus predicted.

Why PHM can be useful

Matching heart size matters. A major size mismatch may affect hemodynamics and post-operative adaptation in certain contexts. PHM is one way to quantify expected heart size more precisely than rough body-size matching alone.

That said, PHM is only one part of decision-making. Clinical teams also consider ventricular function, pulmonary pressures, ischemic time, comorbidities, imaging findings, and many other patient-specific factors.

Interpretation tips

Use accurate measurements for height, weight, and age.
PHM is an estimate, not a direct imaging measurement.
A small difference from predicted can be normal and context-dependent.
Always interpret with clinician oversight in medical settings.

Limitations and important disclaimer

This calculator is for informational and educational use only. It does not diagnose disease, replace echocardiography, MRI, CT, or professional clinical judgment. Equation performance can vary by population and setting. If you are making real medical decisions, consult a qualified healthcare professional.

Quick FAQ

Is this the same as ejection fraction?

No. PHM estimates heart size (mass), while ejection fraction measures pumping function.

Can I use imperial units?

Enter values in metric units in this version. If you have inches/pounds, convert first: height(in) × 2.54 = cm, weight(lb) × 0.453592 = kg.

Does a higher PHM mean a healthier heart?

Not necessarily. PHM reflects expected size, not fitness, valve status, coronary disease burden, or systolic function.