Module orientation
This module belongs to the diagnostic imaging strand and is written for cardiologists who report studies independently, DM and DNB trainees rotating through the echo lab, and intensivists who scan under pressure. It is not a chart to be photographed and forgotten. The teaching aim is different: to build the small number of thresholds that genuinely change management into working memory, and to attach to each one a rule about when it may not be applied. Participants who arrive able to recite cutoffs frequently leave having discovered that they were applying male reference ranges to female patients.
Learning objectives
- Apply body surface area indexing and sex-specific ranges correctly, and explain what goes wrong when they are ignored.
- Report left ventricular size and function volumetrically, adding global longitudinal strain with an awareness of vendor dependence.
- Quantify both atria using the measures current guidance now prefers.
- Produce a right heart report using at least two complementary indices rather than a single number.
- Assemble a filling-pressure statement from primary and supplementary variables, and say when the assessment is indeterminate.
Block 1 — Two rules before any number
The module opens with two governing rules, and every subsequent table is taught as an application of them. The first is indexing. Linear and volumetric measurements should be expressed per square metre of body surface area, because an unindexed atrial dimension carries almost no information in a very small or a very large patient. The second is sex specificity. Most chamber ranges differ between men and women, and using a single set of male-derived cutoffs systematically under-diagnoses dilatation and hypertrophy in women — a bias we demonstrate live by re-reporting archived studies with the correct ranges applied.
A third, quieter rule follows: image quality governs everything. A poorly tracked endocardial border produces a precise number that is simply wrong, and the honest report states that. Participants practise writing the limitation sentence, an underrated skill covered further in the echocardiography course material.
Block 2 — The left ventricle
Linear dimensions retain a role in serial follow-up, but volumes from the biplane method of discs should drive decisions, particularly around valve intervention timing and device eligibility.
| Parameter | Men | Women |
|---|---|---|
| End-diastolic diameter | 42 to 58 mm | 38 to 52 mm |
| End-diastolic volume index | 34 to 74 mL/m² | 29 to 61 mL/m² |
| End-systolic volume index | 11 to 31 mL/m² | 8 to 24 mL/m² |
| Ejection fraction, biplane discs | 52 to 72 per cent | 54 to 74 per cent |
| Septal and posterior wall thickness | 10 mm or less | 9 mm or less |
| Mass index | 115 g/m² or less | 95 g/m² or less |
| Relative wall thickness | 0.42 or less in both sexes | |
Global longitudinal strain earns its own teaching slot because it detects dysfunction while ejection fraction remains reassuringly normal — the situation that matters in cardio-oncology surveillance, amyloid screening and early valve disease. Normal values are more negative than about minus 20 per cent, with a healthy band roughly between minus 16 and minus 22 per cent depending on vendor and software version. That dependence is the clinical caveat: serial comparisons should be made on the same platform, and a change of machine invalidates a trend. Strain acquisition is drilled at length in the echocardiography masterclass.
Block 3 — The atria
Left atrial volume index is the single most informative atrial measurement — a barometer of chronically raised filling pressures and an independent predictor of atrial fibrillation, stroke and death. A normal range of 16 to 34 mL/m² is taught, with values above 34 mL/m² denoting enlargement and progressively higher bands defining moderate and severe dilatation. Linear atrial diameter from the parasternal window persists in reports through habit alone and should not drive interpretation.
Two further measures now belong in routine practice. Left atrial reservoir strain above about 18 per cent is normal, and a value at or below that threshold supports elevated left atrial pressure. On the right, four-chamber right atrial area below 19 cm² provides a quick reproducible screen, while right atrial volume index by method of discs, below approximately 30 mL/m², is the preferred quantitative measure.
Block 4 — The right heart
The right ventricle refuses to conform to a geometric model, so no single index suffices and the module requires at least two to be reported.
| Parameter | Normal |
|---|---|
| Basal diameter, four-chamber | Under 41 mm |
| Mid-cavity diameter | 35 mm or less |
| TAPSE | 17 mm or more |
| Tissue Doppler S wave | Above 9.5 cm/s |
| Fractional area change | Above 35 per cent |
| Free wall longitudinal strain | More negative than minus 20 per cent |
| Proximal outflow tract, parasternal | 35 mm or less |
Both TAPSE and tissue Doppler S interrogate longitudinal motion at the base only, which is why they mislead after cardiac surgery, where longitudinal shortening falls while global right ventricular performance is preserved. Current right heart guidance has also moved towards four-tier severity grading rather than a single abnormal cutoff, so a TAPSE of 12 mm and one of 16 mm are no longer reported identically. Right atrial pressure is estimated from inferior vena caval calibre and collapse — a small, collapsing vessel corresponding to roughly 3 mmHg and a dilated, non-collapsing one to approximately 15 mmHg — and systolic pulmonary artery pressure is the peak tricuspid regurgitant gradient plus that estimate, with a peak velocity of 2.8 m/s or more carrying diagnostic weight.
Block 5 — Filling pressures
Contemporary guidance evaluates three primary variables simultaneously rather than through a stepwise cascade with separate entry points for normal and reduced ejection fraction: e prime velocity, the E over e prime ratio, and tricuspid regurgitant velocity or estimated pulmonary pressure. Abnormal thresholds taught are a septal e prime of 6 cm/s or less and a lateral e prime of 7 cm/s or less; a septal ratio of 15 or more, a lateral ratio of 13 or more, or an average of 14 or more; and a regurgitant velocity of 2.8 m/s or more.
When the primary variables disagree or cannot be obtained, four supplementary measures carry weight: left atrial reservoir strain at or below 18 per cent, pulmonary venous systolic to diastolic ratio at or below 0.67, left atrial volume index above 34 mL/m², and a short isovolumic relaxation time. Grading then runs from impaired relaxation with normal pressures, through a pseudonormal pattern with two or more abnormal primary variables, to a restrictive pattern with all three abnormal. Atrial fibrillation, mitral disease, heavy annular calcification, constriction and prosthetic valves each require a modified approach — participants rehearse these on the case set in the echocardiography atlas for clinicians.
Block 6 — Valves and the aorta
The final block covers the thresholds that trigger referral rather than the full grading schemes. Severe aortic stenosis is defined by a peak velocity of 4 m/s or more, a mean gradient of 40 mmHg or more, or a valve area below 1.0 cm², with the low-flow low-gradient variants requiring stroke volume index and dobutamine testing before a decision is made. Severe mitral regurgitation is supported by an effective regurgitant orifice area of 0.40 cm² or more with a regurgitant volume of 60 mL or more in primary disease. Aortic root and ascending measurements should be indexed and traced from a dedicated view. Trainees preparing for structural referral pathways work through the diagnosis and imaging course book collection.
Self-check
- A 150 cm woman has a left atrial diameter of 40 mm. Is the atrium enlarged? The question cannot be answered from a linear diameter; report the indexed volume.
- Ejection fraction is 58 per cent and global longitudinal strain is minus 14 per cent. Interpretation? Subclinical systolic dysfunction; investigate infiltrative, toxic and ischaemic causes.
- TAPSE is 14 mm on day three after mitral surgery. Does this mean right ventricular failure? Not necessarily — longitudinal indices fall after cardiotomy while global function may be preserved.
- Which single atrial measure best supports elevated left atrial pressure when Doppler is equivocal? Reservoir strain at or below 18 per cent.
- Peak tricuspid velocity is 3.1 m/s with a dilated non-collapsing cava. Estimated systolic pulmonary pressure? Roughly 38 plus 15, that is about 53 mmHg.
How this module is taught in the course
The module is delivered as a reporting workshop rather than a lecture. Participants receive twenty anonymised studies, report them against the tables above, and then compare their numbers with a consensus reading; the discussion focuses on disagreements rather than on the studies everyone read identically. A laminated summary card is issued for lab use, and the measurement technique behind each threshold is revisited in the intermediate level echocardiography course and in scheduled live echocardiography classes. The continuous reference version of these tables remains available as the adult echocardiography normal values reference chart.
Module FAQ
Should I memorise every number in this module?
No. Memorise the thresholds that change management — volume index, mass index, TAPSE, the three primary diastolic variables and severe valve criteria — and keep the rest accessible.
Can strain replace ejection fraction in reporting?
It complements rather than replaces it. Report both, and record the vendor so that serial comparisons remain valid.
How do I report when image quality is poor?
State which measurements were not obtainable and why, give the values you trust, and avoid producing a falsely precise composite conclusion.
Is the module useful for critical care echocardiography?
Yes, particularly the right heart and filling pressure blocks, though loading conditions in ventilated patients require the caveats taught in the final session.