Echocardiography (synonyms: cardiac echo; ultrasound of the heart; cardiac ultrasound) is a special ultrasound examination of the heart. It is used to diagnose heart disease.
Indications (areas of application)
- Diseases of the heart valves, such as aortic valve stenosis or insufficiency, mitral valve stenosis or insufficiency
- Cardiac thrombi (blood clots) in one of the heart’s internal chambers – can be caused, for example, by cardiac arrhythmias such as delirium cordis – atrial fibrillation -, or by valvular defects such as mitral valve stenosis
- Assessment of the function of artificial heart valves
- Aneurysm (wall protrusion) – malformation of the aorta (main artery) or heart wall.
- Hemodynamically unstable patient, such as:
- Heart failure (cardiac insufficiency) – including differentiation of systolic from diastolic dysfunction.
- Cardiomyopathies (heart muscle diseases).
- Openings between the heart chambers, such as a persistent foramen ovale (PFO; patent foramen ovale) or a structural atrial septal defect
- Pericardial effusion – accumulation of fluid in the pericardium.
- Storage diseases (e.g., amyloidosis)
The procedure
There are several ways to perform an ultrasound examination of the heart. These include, for example. Transthoracic echocardiography: this is done through the chest. The ultrasound probe is placed on the outside of the anterior chest wall. Beforehand, some gel is applied to this chest area so that the ultrasound machine’s transducer glides well and transmission is improved. The patient’s upper body is slightly raised, and the left arm is placed behind the head. The sound waves emitted by the device are reflected by the body tissue to varying degrees and reflected back as an “echo”. This is electronically converted into an image and is visible on the screen. Transesophageal echocardiography (TEE): This is performed via the esophagus, which runs in a section directly next to the heart. After administering a sedative (calming medication), a special transducer is inserted transesophageally (through the mouth into the esophagus) and accordingly brought close to the heart. This allows better visualization of certain heart structures, especially the left atrium (heart atrium; e.g., to exclude thrombi/blood clots). Exercise echocardiography, stress echocardiography: Here, too, the examination is performed via the chest, with simultaneous increase in cardiac work. The increased cardiac activity is induced either by ergometer stress – on a fixed bicycle – or by medication (usually dobutamine). The load-dependent contraction of the heart is observed. If contraction disorders occur, this may indicate coronary stenosis (narrowed coronary vessels), for example. In all forms of echocardiography, in addition to imaging the heart, a (pulsed) Doppler sonography is also performed to analyze the blood flow (= Doppler echocardiography). A color Doppler echocardiography also shows the direction of the blood flow in different colors. This can be used primarily to determine valvular heart disease (heart valve defects) or septal defects (holes in the cardiac septum). Sonography of the heart depicts:
- Structure of heart walls and valves and their motion patterns.
- Wall thickness of heart atria and ventricles
- Size of the inner chambers of the heart and thus the overall heart size.
- Cardiac output per minute (HMV)
- Disturbances of systolic and diastolic function, respectively.
Standardized examination sections of a transthoracic echocardiography. Mod. after.
| Cut | Modality(ies) | Possible measurements |
| Parasternal longitudinal section | 2D, color Doppler, mode a | LVEDD, LVESD, IVS, LVPW, LVOT (2D), Ao (2D) |
| Parasternal cross-section (aorta). | 2D, color Doppler, M-mode a | |
| Parasternal cross section (MK) | 2D | |
| Parasternal cross section (LV) | 2D, M-mode | LVEDD, LVESD, IVS, LVPW |
| Parasternal RV influence tract b. | 2D, color Doppler | |
| Parasternal RV outflow tract b | 2D, color Doppler, PW | RVOT (2D, PW) |
| Apical four-chamber view | 2D, color Doppler, PW, CW, TDI | LAV, LVEDV, LVESV, EF, E, A, E/A, DT, e’, E/e’, TK (CW) |
| Apical five-chamber view | 2D, color Doppler, PW, CW | LVOT (PW), AK (CW) |
| Apical bicameral view | 2D, color Doppler | LVEDV, LVESV, EF |
| Apical longitudinal section | 2D, color Doppler | |
| Subcostal four-chamber view b | 2D, color Doppler | |
| Subcostal VCI + “sniff” | M-Mode |
a M-mode measurements can be made from the longitudinal or transverse section. Some ultrasound machines allow anatomic M-mode from the archived B-scan.b optional sections: A: late diastolic velocity (mitral flow); AK: aortic valve; Ao: aorta; DT: deceleration time; E: early diastolic velocity (mitral flow); e’: early diastolic velocity (mitral annulus); EF: ejection fraction (ejection fraction); IVS: interventricular septum; LAV: left atrial volume; LVEDD: inksventricular end-diastolic diameter; LVEDV: left ventricular end-diastolic volume; LVESD: left ventricular end-systolic diameter; LVESV: left ventricular end-systolic volume; LVOT: left ventricular outflow tract; RVOT: right ventricular outflow tract; LVPW: left ventricular posterior wall; TK: tricuspid valve; VCI: inferior vena cava.
Standardized measurement protocol of transthoracic echocardiography. Mod. according to
| Measurements | Normal values |
| Left ventricular size | |
| 2D or 3D volumes a |
|
| LV Diameter (M-Mode, 2D) |
|
| Septum and posterior wall thickness(M-mode). |
|
| LVEF |
|
| Regional wall motion analysis(score index) b |
|
| LAV |
|
| Right ventricle (size): normal or dilated. | |
| Right ventricle (function): normal, low,moderate, or high reduced. | |
| Right atrium (size): normal or dilated | |
| Aortic root (sinus) c |
|
| IVC Diameter |
|
Legend
- A The indexed values are to be preferred.
- B 16- or 17-segment model.
- C In case of (susp. ) Pathology: ascending aorta; sinotubular junction; EDD: end-diastolic diameter; EDV: end-diastolic volume; ESD: end-systolic diameter; ESV: end-systolic volume; IVC: inferior vena cava; IVS: interventricular septum; LAV: left atrial volume; LVEF: left ventricular ejection fraction (ejection fraction); LVPW: left ventricular posterior wall.
Reference values of left ventricular volumes and ejection fraction. Mod.to
| Unit | Normal | Low | Abnormal Moderate | High Grade | |
| Women | |||||
| LVDV | ml | 56-104 | 105-117 | 118-130 | > 130 |
| LVDV index | ml/m2 BSA | 35-75 | 76-86 | 87-96 | > 96 |
| LVSV | ml | 19-49 | 50-59 | 60-69 | > 69 |
| LVSV index | ml/m2 BSA | 12-30 | 31-36 | 37-42 | > 42 |
| EF | % | > 54 | 45-54 | 30-44 | < 30 |
| Men | |||||
| LVDV | ml | 67-155 | 156-178 | 179-201 | > 201 |
| LVDV index | ml/m2 BSA | 35-75 | 76-86 | 87-96 | > 96 |
| LVSV | ml | 22-58 | 59-70 | 71-82 | > 82 |
| LVSV index | ml/m2 BSA | 12-30 | 31-36 | 37-42 | > 42 |
| EF | % | > 54 | 45-54 | 30-44 | < 30 |
Legend
- EF: ejection fraction (ejection fraction).
- LVDV: left ventricular diastolic volume.
- LVSV: left ventricular systolic volume.
Duration of the examination: 20 to 30 minutes
