Ejection Fraction Measurement: Teichholz vs. 2D Modified Simpson's Method
The 2D modified Simpson's biplane method is more accurate than the Teichholz (M-mode) method for measuring ejection fraction, particularly in patients with abnormal ventricular geometry, and should be your preferred technique in clinical practice. 1
Why These Methods Differ
The fundamental reason for discrepancies between these two methods lies in their geometric assumptions:
Teichholz Method (M-mode) Limitations:
- Assumes the left ventricle is a prolate ellipsoid with a fixed 2:1 long/short axis ratio 1
- Uses a single linear dimension that is cubed in the calculation, meaning even small measurement errors are magnified significantly 1
- Consistently overestimates ejection fraction by approximately 10% compared to reference standards 2, 3
- Particularly inaccurate in:
- Dilated ventricles
- Asymmetric hypertrophy
- Regional wall motion abnormalities
- Any condition causing abnormal LV geometry 1
2D Modified Simpson's Method Advantages:
- Makes no geometric assumptions about cavity shape 1
- Directly measures the actual ventricular contour from multiple imaging planes
- Accommodates for shape distortions and changes in LV size along the long axis 1
- Shows better correlation with left ventricular global strain (r=0.710 vs r=0.44 for visual assessment) 4
- Demonstrates no significant difference from cardiovascular magnetic resonance (the gold standard), with mean EF of 31±10% vs 30±11% respectively (P=0.23) 5
Clinical Accuracy Comparison
Research directly comparing these methods reveals:
- Teichholz method overestimates EF compared to both Simpson's method and nuclear imaging 5, 3
- In heart failure patients, mean EF by Teichholz was 29±15%, while Simpson's biplane was 31±10% 5
- The Bland-Altman limits of agreement between cardiovascular magnetic resonance and Simpson's 2D echo (44%) were narrower than between MRI and Teichholz M-mode (66%) 5
- Simpson's method shows better inter-observer reliability and is more suitable for serial assessments 6
Common Pitfalls to Avoid
With Teichholz/M-mode:
- Off-axis beam orientation is frequent and introduces major errors 1
- The method is only "fairly accurate in normally shaped ventricles" (e.g., systemic hypertension, aortic stenosis without regional abnormalities) 1
- Do not use in patients with regional wall motion abnormalities or dilated cardiomyopathy 1
With Simpson's Method:
- Requires adequate image quality—only 69% of studies may be analyzable vs 86% for M-mode 5
- Must avoid foreshortening of the left ventricle, which causes volume underestimation 1
- Requires measurements from both apical four-chamber and two-chamber views 1
Practical Recommendation Algorithm
Use Simpson's biplane method when:
- Patient has any cardiac disease (most clinical scenarios)
- Abnormal ventricular geometry is present or suspected
- Serial measurements are needed for monitoring
- Accurate prognostic information is required
Teichholz may be acceptable only for:
- Large population screening where speed is essential 1
- Patients with confirmed normal ventricular geometry
- When image quality prevents adequate Simpson's measurement
Critical note: The 2015 ASE/EACVI guidelines explicitly state that "the Teichholz and Quinones methods for calculating LV volumes from LV linear dimensions are no longer recommended for clinical use" 1. This represents the strongest evidence-based position against routine use of the Teichholz method.
The discrepancy you observe between these methods is expected and clinically significant—they are not interchangeable 5. When managing individual patients, particularly those with heart failure or structural heart disease, always prioritize the Simpson's biplane method for clinical decision-making.