13.2 LV and LA Size, Geometry, Volumes, Mass, and Function
Key Takeaways
- Nonforeshortened apical planes, defined end-diastolic and end-systolic frames, valid endocardial borders, and representative beats precede every LV or LA calculation.
- Biplane disks or high-quality 3-D data quantify LV volumes; index size to BSA and preserve method, loading, rhythm, and image quality when comparing serial studies.
- LV geometry combines sex-specific indexed mass with RWT, while EF and strain remain loading-, method-, and image-quality dependent measures of function.
- Maximal LA volume is traced just before mitral opening, excludes pulmonary veins and appendage, and is indexed to BSA; enlargement reflects chronic context rather than instantaneous pressure alone.
Start with reproducible planes and cardiac timing
Chamber quantification is only as valid as the plane that created it. Record blood pressure, heart rate, rhythm, height, and weight; calculate body surface area for indexed measures. Acquire nonforeshortened apical four- and two-chamber views with the LV apex at the sector's far field and the long axis centered. The apex should not appear rounded, and the long-axis lengths from the two apical views should be similar. Move the transducer rather than merely steering a foreshortened image. Foreshortening underestimates volumes and can distort ejection fraction.
Measure at defined times. LV end-diastole is the frame at mitral closure or the largest cavity, and end-systole is at aortic closure or the smallest cavity. Use ECG and valve motion when timing is unclear. In sinus rhythm, average representative beats according to laboratory protocol; irregular rhythm requires more beats and selection with similar preceding cycle lengths. Avoid postectopic beats. Loading, heart rate, rhythm, ventilation, and blood pressure can change size and function without structural progression, so preserve them for serial comparison.
Quantify LV size, volume, and ejection
| Measure | Recommended approach | Major limitation |
|---|---|---|
| LV linear dimensions | 2-D-guided parasternal long-axis plane, perpendicular to long axis at mitral leaflet tips | Oblique cuts exaggerate diameter; a single dimension misses asymmetric remodeling |
| EDV and ESV | Biplane method of disks from nonforeshortened apical four- and two-chamber contours | Poor border, apical truncation, and inconsistent basal closure alter every disk |
| 3-D volumes | Full-volume dataset with complete LV and adequate temporal resolution | Stitching, dropout, vendor algorithms, and incomplete pyramids; volumes may differ by method |
| Ejection fraction | (EDV − ESV) / EDV × 100 using the same method and valid beats | Load, rhythm, border error, and geometric assumptions; EF is not contractility alone |
| Stroke volume | EDV − ESV or validated Doppler flow calculation | Small diameter error is squared in Doppler area and compounds with VTI error |
For biplane volumes, trace the compacted myocardium–cavity interface at end-diastole and end-systole. Do not contour around papillary muscles or trabeculations; exclude them from the tracing so they remain part of the LV chamber or blood pool for volume calculation. Set the basal line across the mitral annular plane without including LA. When two contiguous endocardial segments are not visible, optimize frequency, gain, depth, and harmonic settings; use ultrasound-enhancing agent according to protocol rather than inventing a border. Three-dimensional volumes avoid geometric assumptions and are preferred when complete, high-quality datasets are feasible. Preserve the acquisition and analysis method because 2-D, 3-D, and contrast values are not interchangeable without context.
Index EDV and ESV to body surface area and apply the laboratory's age-, sex-, and method-specific reference ranges. For 2-D LVEF, conventional normal ranges are 52%–72% in men and 54%–74% in women. Do not describe a ventricle as normal from EF alone: report size, geometry, regional wall motion, global function, and, when indicated, cardiac output and myocardial deformation. EF may be preserved despite reduced longitudinal function or low stroke volume and may fall with acute afterload elevation. GLS adds sensitivity but remains vendor-, tracking-, loading-, and image-quality dependent; use the same platform and convention for serial work.
Calculate LV mass and define geometry
Measure interventricular septum, LV internal diameter, and posterior wall at end-diastole from a perpendicular parasternal long-axis plane. The cube formula magnifies small errors, so off-axis measurement, inclusion of RV trabeculation, or misplacement beyond the compact myocardium can substantially change mass. Index mass to BSA and use sex-specific limits; conventional upper normal LV mass index is 115 g/m² for men and 95 g/m² for women. Relative wall thickness, or RWT, is 2 × posterior wall thickness / LV internal diameter at end-diastole; RWT greater than 0.42 is increased.
| LV mass index | RWT | Geometry |
|---|---|---|
| Normal | ≤0.42 | Normal geometry |
| Normal | >0.42 | Concentric remodeling |
| Increased | >0.42 | Concentric hypertrophy |
| Increased | ≤0.42 | Eccentric hypertrophy |
Geometry describes remodeling, not its cause. Hypertension, valve disease, athletic adaptation, infiltrative disease, and loading can overlap, and wall thickness is not synonymous with mass. Review image quality, clinical setting, and serial pattern before assigning physiology.
Measure LA volume rather than relying on one diameter
The LA is asymmetric, so an anteroposterior linear diameter can miss enlargement. Measure maximal LA volume at ventricular end-systole, immediately before mitral opening, from dedicated nonforeshortened apical four- and two-chamber views. Trace the blood-tissue boundary, exclude pulmonary veins and the LA appendage, and close the contour across the mitral annulus. Use biplane disks when both views are valid and index volume to BSA. A conventional LAVI of 34 mL/m² or less is normal; 35–41 is mildly, 42–48 moderately, and greater than 48 severely enlarged.
LA enlargement often reflects cumulative exposure to elevated filling pressure, mitral disease, or AF, but it is not a direct instantaneous pressure measurement. Acute pressure elevation may occur before dilation, while athletic remodeling, high output, obesity, and chronic AF can enlarge the LA through different pathways. Indexing to BSA can also mask obesity-related enlargement. Interpret LA volume with Doppler filling evidence, valve disease, rhythm, and clinical context. Report the method, indexed result, and image limitation. Serial conclusions are strongest when planes, beats, border convention, and analysis platform match.
Confirm unexpected serial change
Verify plane, timing, border, beat selection, loading, and analysis method before labeling an unexpected numerical difference as true remodeling.
Reacquire a foreshortened apex
If one apical long axis is visibly shorter or the apex is rounded, move the transducer to expose the true apex before tracing. A precise contour cannot repair a truncated ventricle or atrium, and numerical reproducibility does not rescue a systematically biased plane.
The apical two-chamber LV is visibly shorter than the four-chamber LV and has a rounded apex. What is the best action before calculating biplane volumes?
Match each LV remodeling pattern with its mass-index and relative-wall-thickness combination.
Match each item on the left with the correct item on the right