Echocardiography (ultrasound examination of the heart, ECHO, UCG) has a central role as a non-invasive heart examination that can be performed in outpatient care.
It gives a comprehensive picture of the heart's structure and function.
Echocardiography is performed at the office of a cardiologist, other physician familiar with the method or a sonographer (ultrasound nurse) and requires no preparation.
Echocardiography gives a good idea of the contraction (systolic function), relaxation (diastolic function) and structure of the heart.
It is the first-line examination in the diagnosis and follow-up of valvular diseases.
This article discusses only transthoracic echocardiography (TTE) in adults.
Indications
The main indications for echocardiography include
investigation of murmurs
investigation of symptoms suspected of being of cardiac origin, such as dyspnoea or chest pain
diagnosis, grading and follow-up of valvular diseases
diagnosis of heart failure (systolic/diastolic / filling pressure)
diagnosis of cardiomyopathies.
In addition, echocardiography can be used to investigate
the aetiology and prognosis of arrhythmias
the differential diagnosis of chest pain
the diagnosis of peri- and myocarditis
the state of congenital heart defects in adults
problems following heart surgery
the state of the ascending aorta
cardiac effects of the treatment of other diseases (e.g. cytotoxic drugs, radiotherapy)
the possibility of cardiac embolism
pulmonary arterial pressure.
Echocardiography is increasingly used in acute situations, such as acute coronary syndrome (wall motion abnormality), in emergency and critical care settings and in situations involving resuscitation.
Technology of echocardiography
Two-dimensional grey scale imaging (2D imaging)
Basic examination quickly providing a general impression of heart structure and function.
The image can be used to measure
the thickness of the myocardium
the size of various parts of the heart (atria, ventricles, ascending aorta, inferior vena cava)
pumping function.
To assess
any structural abnormality
the state of the pericardium / pericardial effusion
the structure and function of the valves (e.g. calcification, prolapse).
Doppler examinations
To study blood flow.
Colour Doppler shows the direction and velocity of blood flow and any turbulence.
Valvular defects
Shunts
Pulsed and continuous wave Doppler measure the direction and velocity of blood flow.
To determine the severity of valvular defects
Tissue Doppler measures the velocity of myocardial motion.
Particularly to assess diastolic function
Other ultrasound techniques
M-mode ultrasonography, one-dimensional
Excellent temporal and spatial resolution but very limited measuring area
Strain imaging
Measures deformation of the myocardium.
The most sensitive method to detect mild or early disturbances in myocardial function
3D (4D) imaging
Forms a three-dimensional image of the heart that can be viewed from various directions.
A demanding technique that may at best give an anatomical picture of the various heart structures.
Exercise echocardiography
The effect of stress (induced by a drug or by physical exercise) on myocardial contractility (ischaemia causes wall motion abnormalities) or valve function (functional mitral regurgitation, for example, increases during stress) is followed.
This is a demanding technique not widely used everywhere.
Main measurements with reference values
Reference values may vary from country to country. Check locally applied values.
Left ventricular end-diastolic dimension
Reference values
Women < 53 mm
Men < 59 mm
Left ventricular ejection fraction (EF; the share of the total volume of blood in the heart pumped during one beat)
Reference value > 55%
Slightly reduced 45-54%
Moderately reduced 36-44%
Severely reduced ≤ 35%
Mitral regurgitation, effective regurgitant orifice area (ERO)
Severe regurgitation: ERO ≥ 0.40 cm2
Moderately severe regurgitation: 0.20-0.39 cm2
Mild regurgitation: < 0.20 cm2
Aortic stenosis, aortic valve area (AVA)
Severe stenosis: AVA < 1.0 cm2
Moderately severe stenosis: 1.0-1.4 cm2
Mild stenosis: ≥ 1.5 cm2
Tricuspid annular plane systolic excursion (TAPSE) reflecting right ventricular function
Right heart strain/failure (massive pulmonary embolism, right ventricular infarction)
Acute chest pain - differential diagnosis
Wall motion abnormality suggesting ischaemia
Dissection of the ascending aorta
Massive pulmonary embolism
Myo-/pericarditis
Pleural effusion
Limitations of echocardiography
Visibility: ultrasound passes bone and air poorly
The heart is visible only through certain “windows”.
Visibility is restricted by
pulmonary emphysema
abundant subcutaneous fat
very large size of the patient
wound dressings, breast implants, other foreign bodies in the area.
Coronary arteries are not visible without special techniques, i.e. echocardiography cannot be used to assess the extent and severity of coronary artery stenosis.