Echocardiography in Clinical Practice
On this page
Direct answer
Echocardiography is ultrasound imaging of the heart that measures chamber size, ejection fraction, valve function and filling pressures without radiation. Transthoracic echo is the first-line test for valve disease, cardiomyopathy and pericardial effusion, while transoesophageal echo answers the questions the chest-wall study cannot, such as endocarditis or left atrial thrombus. A normal left ventricular ejection fraction is roughly 55 to 70 per cent in most adults.
What you must remember
- Core views: parasternal long axis, parasternal short axis, apical four-chamber and apical two-chamber views form the basic set, with subcostal and suprasternal views added for the IVC and aortic arch.
- Ejection fraction: biplane Simpson's method is the standard quantitative technique, because visual estimates are less reliable for borderline results.
- Doppler gradient: the modified Bernoulli equation gives gradient = 4 × V², so a peak velocity of 4 m/s corresponds to about 64 mmHg.
- Mitral valve area: pressure half-time gives valve area as 220 divided by the half-time in milliseconds, and the mean gradient comes from continuous wave Doppler.
- Diastolic grading: normal, grade I (impaired relaxation), grade II (pseudonormal) and grade III (restrictive) are separated by E/A ratio, deceleration time and E/e' values.
- Filling pressure: an average E/e' above 14, with peak tricuspid regurgitant velocity above 2.8 m/s, suggests raised left ventricular filling pressure.
- TOE indications: suspected endocarditis with uncertain vegetations, prosthetic valve dysfunction, left atrial appendage thrombus and suspected aortic dissection are the classic reasons to proceed to transoesophageal study.
A systematic review that avoids missed findings
A reliable echo report follows the same order every time, so that no valve, chamber or pressure estimate is skipped. Each step either confirms a finding or sends the reader to a more specific measurement.
- Check study quality: Confirm that the views are adequate and the apex is not foreshortened, because foreshortening distorts volumes and makes the ejection fraction unreliable.
- Measure chambers and function: Record left ventricular dimensions, volumes and ejection fraction, and note regional wall motion abnormalities using the 17-segment model.
- Grade each valve: Use colour Doppler, continuous wave velocity and the continuity equation to grade stenosis and regurgitation. An aortic valve area below 1.0 cm² indicates severe stenosis.
- Estimate filling pressure: Combine E/A, E/e', deceleration time and tricuspid regurgitant velocity to grade diastolic function, which matters in heart failure with preserved ejection fraction.
- Estimate pulmonary pressure: Systolic pulmonary artery pressure equals four times the tricuspid regurgitant velocity squared, plus the right atrial pressure estimated from the IVC.
- Look for pericardial and aortic disease: Check for effusion, right atrial or ventricular diastolic collapse, respiratory variation in mitral inflow, and the aortic root and ascending aorta.
Where the examiner catches the echo error
Echo questions usually test whether a number is read in context rather than in isolation.
- Trap: reassuring yourself with a normal ejection fraction in mitral regurgitation Correct: in severe chronic primary mitral regurgitation, an ejection fraction of 60 per cent or less, or an end-systolic dimension of 40 mm or more, signals that surgery should be considered.
- Trap: equating a high Doppler velocity with a tight valve Correct: velocity rises with flow, so a high gradient in a low-output patient needs the continuity equation before severity is graded.
- Trap: ordering transoesophageal echo for every murmur Correct: the probe usually needs throat anaesthesia and sedation, so it is reserved for questions the transthoracic study cannot answer.
Frequently asked questions
Which view is used to measure the aortic valve gradient?
Continuous wave Doppler from the apical five-chamber view gives the peak and mean aortic gradient, because the beam can be aligned with the high-velocity jet. Angle errors underestimate velocity and therefore the gradient, so careful alignment matters.
What is the normal ejection fraction on echocardiography?
A normal left ventricular ejection fraction is roughly 55 to 70 per cent in most adults, measured by biplane Simpson's method. A value around 40 per cent or less defines heart failure with reduced ejection fraction.
Which echo finding suggests raised left atrial pressure?
An average E/e' above 14, together with a peak tricuspid regurgitant velocity above 2.8 m/s, suggests raised left atrial pressure. These measurements are most useful when combined, rather than read from a single value.
When is transoesophageal echocardiography preferred?
Transoesophageal echo is preferred for endocarditis with uncertain vegetations, prosthetic valve dysfunction, left atrial appendage thrombus and suspected aortic dissection. The oesophagus lies close to the left atrium and descending aorta, so these structures are imaged more sharply than from the chest wall.