Echocardiography

How is the heart controlled?

Valve errors are diagnosed by echo.

Echocardiography is a method of examining the heart. The heart is represented by an ultrasound. This makes echocardiography, next to electrocardiography (EKG), one of the most important non-invasive examinations of the heart.

The various methods of echocardiography (transthoracic echocardiography, transesophageal echocardiography and stress echocardiography) are not only used to diagnose diseases of the heart, but are also used to monitor the progress. For example, both heart valve diseases and heart muscle weakness are checked approximately every six to 12 months using echocardiography.

Even after heart surgery, the Function of the heart controlled using echocardiography, among other things. The check-up runs like previous echocardiography examinations. As part of this control echocardiography, special attention is paid to one Worsening heart function. A deterioration in heart function is caused, for example, by a Decrease in the pumping function or by a Enlargement of the heart due to heavy loads, clearly.

Control of the heart can be in special centers outpatient respectively. This means that the patient can go home after the examination. The Stress echocardiography ("stress echo") is used in particular to Follow-up of coronary heart disease (CHD), applied. Coronary artery disease involves changes in the coronary arteries that cause the Heart muscle supply with blood. In the worst case, it comes to one complete closure of a coronary arterywhy here too regular checks are necessary.
Coronary artery disease worsening if Termination criteriasuch as reaching the target heart rate or the occurrence of chest pain, can be achieved earlier than in the previous stress echocardiography exam.

Investigation methods

There are several ways to perform echocardiography. The standard method is transthoracic echocardiography (TTE). The ultrasound head is placed on the chest and the heart is viewed. It is also possible to pass through the heart esophagus to judge. This is called transesophageal echocardiography (TEA) designated. Another examination method is an ultrasound examination of the heart under pressure.

Transthoracic Echocardiography (TTE)

This form of echocardiography is the Standard examination and is referred to as "echo" designated. First, the heart is examined by placing the ultrasound head on the Rib cage examined. The two most important positions of the ultrasound head are included parasternal, so to the left of the sternum, and from apical, i.e. from the apex of the heart. Through further starting points, as on the right under the Ribs (subcostal), for example, the great hepatic vein can be viewed. The ultrasound head can also be placed above the sternum to gain a wider perspective of the heart. The heart and its function can be assessed using various settings on the ultrasound device.

in the 2-D image will the Cardiac function visible in real time as a black and white cross-sectional image. Especially those Size of the heart chambers, the Function of the flaps and the Pump function of the heart can be represented well. So can the Ejection capacity of the heart (Ejection fraction) can be determined. In a longitudinal section or by looking at it from the suprasternal perspective (above the sternum), the aorta and the Aortic arch be considered, for example, the life-threatening disease of the Aortic dissection to recognize.
Of the M-mode serves the one-dimensional Representation of motion sequences. This allows the movements of the aortic and mitral valves to be displayed on a one-dimensional, horizontal line. The pumping function of the left ventricle (left ventricle) can thereby be made visible. Of the PW- and CW Doppler represent a one-dimensional method of applying the Doppler effect With the help of the Doppler effect, blood flow velocities can be measured. This allows Valvular heart disease, Constrictions (Stenoses) or Short circuit connections (Shunts) getting discovered. The color Doppler allows the venous and arterial flow to be separated by color. In this way, valve insufficiency or stenosis in particular, but also shunt connections, can be displayed in color and localized.

Transesophageal Echocardiography (TEE)

The Transesophageal echocardiography refers to the ultrasound scan of the heart by the esophagus (Esophagus) out. This examination is a little more invasive and uncomfortable for the patient. As a rule, the patient is given a Sleeping pills numbed so that the examination is not uncomfortable.

Then a flexible tube, which has a small ultrasound probe at its end, is pushed through the mouth and throat into the esophagus. Since no bones, muscles or fat obstruct the view during this examination, the visualization of the heart is often better. Especially small ones Blood clots (Thrombi) can be in the Auricular ears or the Atria of the heart are well known.

Due to the mobility of the ultrasound probe around its own axis, all layers of the heart can be displayed. The most common indication for this form of invasive echocardiography is poor assessability, due to a Obesity, one Emphysema or other anatomical conditions, in classical echocardiography.

Stress echocardiography

This form of representation of the heart takes place under load and is for this reason also called "Stress echo" designated. The most common indication for carrying out this examination is the suspicion of a circulatory disorder of the heart as part of a coronary artery disease (CHD).
The stress can be caused in two ways. As part of the mechanical load, the patient lies in Left lateral position on one Exercise bike. While the patient is pedaling with slowly increasing resistance, the doctor carries out an ultrasound scan of the heart. Another possibility is to use drugs to induce stress. This is done when patients are unable to ride a bike due to physical limitations. Intravenous drugs are used to put stress on the heart with medication Dobutamine or Adenosine or Dipyridamole With Atropine administered.

The drugs lead to an increase in Heart rate and an increased Stroke volume and Cardiac output. As a result, the heart reaction that triggers sport is provoked by medication.
Regardless of the type of stress, a “stress echo” is carried out in several stress levels. Initially, the left ventricle is always displayed at rest. Then the load is slowly increased until termination criteria are met. This includes reaching the Target heart rate, Chest pain of the patient or visible wall movement disorders in the ultrasound.
Chest pain or wall movement disorders during the "stress echo" are clear indications of the presence of coronary artery disease (CHD). During the examination, the Ejection phase (Systole) of the heart in the apical 4-chamber view, in the apical 2-chamber view and in the parasternal long and short axis.

These recordings are made in the various Load levels. The stress levels of a glance can then be played back synchronously. This makes it easier to find possible wall movement disorders.

Heart attack

When diagnosing one Heart attack echocardiography can play an important role. If you have a heart attack, you will Closure of vesselswhich the heart normally uses blood supply the coronary arteries. If a coronary artery is blocked, it comes to one Oxygen deficiency of parts of the heart muscles and subsequently to the This undersupplied heart muscle area dies.

Most are Blood clots responsible for the occlusions of coronary arteries. The formation of these blood clots is caused by various risk factors, how Smoking, being overweight or having high blood pressure favored. The diagnosis of a heart attack is made using various examination methods. First the detailed inquiries about the complaints of the patient (anamnesis). In the case of a heart attack, patients often complain about Pressure or tightness, such as Chest pain. In addition to the questioning, an electrocardiography (EKG) is always carried out. Here you can often typical changessuggestive of a heart attack. Also, according to certain Heart attack markers (certain Enzymesshowing the breakdown of heart muscles) in the patient's blood. However, these parameters only rise after a few hours and cannot yet be measured in the blood in the early phase of the heart attack.

A process that already disrupts early (even before the myocardial infarction markers rise in the blood), echocardiography is, which is why this examination method plays an important role in heart attack diagnosis. The death of heart muscles means that the heart can no longer contract properly at this point, it comes to one Movement disorder of the heart muscle. This movement disorder is visible on echocardiography. In this way, a fresh heart attack can be detected before the heart attack markers rise in the blood. If the echocardiography does not reveal any movement disorders of the heart muscles, a heart attack can be ruled out with a very high probability.

To treat the heart attack, the Blockage in the affected coronary artery eliminated become. This is done either by a drug dissolution the blood clot or a mechanical expansion of the narrowed area by means of Cardiac catheter. After a heart attack, the loss of heart muscles can lead to complications such as a decreased pump performance of the heart or to Dysfunction of the heart valves come. Therefore, after the coronary artery occlusion has been removed, another echocardiography examination is often performed. Here the mentioned potential complications after a heart attack would become visible and further treatment measures could be initiated.

As part of myocardial infarction diagnosis Transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE) only. A Stress echocardiography ("Stress echo") is allowed in the event of a heart attack and up to two weeks after a heart attack under no circumstances should be carried out, because the increased heart rate would put additional stress on the heart and thus an even poorer oxygen supply to the heart muscle.

Measured values ​​/ standard values

There are standard values ​​for the vessels and valves.

A goal of Echocardiography is the assessment of the proportions of the heart. In addition, the function of the various heart valves checked. To decide whether a reading is abnormal or normal, exist Standard values ​​as general guidelines. However, it should be remembered that the size of the heart also depends on the height depends on the patient and thus differs from person to person. Of particular interest in the heart are the diameters of the individual chambers and surrounding vessels, such as the aorta. In the following, normal values ​​of relevant anatomical structures of the heart are listed in echocariography and starting in the physiological blood flow Vena cava sorted.

The blood passes through the superior and inferior vena cava (Vena cava superior / inferior), which are approximately 20 mm wide, from the great bloodstream to the right atrium (Atrium) of the heart. This normally has a diameter of less than 35 mm. From there the blood reaches them right chamber (Ventricle) via the so-called Tricuspid valve. The wall of the right ventricle shows in the heart echo to be much thinner compared to the left ventricle. The reason for this is the much lower resistance, namely the pulmonary circulation against which the right ventricle has to pump the blood. In addition, the diameter of the right ventricle is approximately 25 mm slightly smaller than that of the left. Here it should be less than 45 mm be. The wall (Septum) between the chambers normally has a thickness of 10 mm. If the right ventricle now contracts, it opens Pulmonary valve and the blood flows through the lungs to the left atriumwhose diameter is approximately 40 mm amounts. On the way to the aorta, the blood passes two other valves, namely the first Mitral valve and then the Aortic valve. The diameter of the aorta is still at its root 40 mm, but shrinks to approximately in the further course 25 mm.

In addition to measuring the previously mentioned cavities, echocardiography also uses the Function of the heart valves checked. This is done using the Doppler method. This makes it possible to measure the speed of the blood flow. The following speeds should prevail on the four heart valves:

  • Aortic valve 1.0-1.7 m / s
  • Mitral valve 0.6-1.3 m / s
  • Pulmonary valve 0.6-0.9 m / s
  • Tricuspid valve 0.3-0.6 m / s

In addition to measuring the heart cavities and the surrounding vessels and determining the flow velocities over the heart valves, echocardiography can be used to determine other measured values. With the help of echocardiography, the Pumping power of the heart be estimated. The values ​​provide information about this end-diastolic volume, end-systolic volume, stroke volume and ejection fraction.

The end-diastolic volume represents the amount of blood that is in the heart after maximum filling and is between in healthy people 130 and 140 ml. The end-systolic volume is the amount of blood that is still in the heart after a heartbeat and is around in healthy people 50 to 60 ml. The stroke volume denotes the amount that ejected into the circulatory system per heartbeat becomes. The stroke volume is between 70 and 100 ml. With the help of the stroke volume and the end-diastolic volume, another value can be calculated, the so-called ejection fraction. The ejection fraction indicates the percentage of blood ejected in relation to the amount of blood after maximum filling in the heart. The ejection fraction is in healthy people over 55 percent.

With echocardiography, the Heart rate be determined. It states how often that Heart beats per minute and is between 50 and 100 Beats per minute. The heart rate is depending on age and from Training condition the person to be examined. Have so older people as well as very sporty peoplen usually one low heart rate, sometimes even below 50 beats per minute, but do not show any disease value. With the help of stroke volume and heart rate, another value can be calculated that also provides information about the pumping capacity of the heart Cardiac output. Cardiac output is the amount of blood that is pumped from the heart into the body's circulation per minute. The normal cardiac output is 4.5 to 5 liters per minute. All values ​​mentioned apply to healthy adults and vary according to gender.

evaluation

To Evaluation of an echocardiography the doctor usually has a ready-made form that he must fill out. After the names of the doctor and patient have been entered, the doctor must specify which method he used exactly. Then it comes to Assessment of the individual heart cavities according to the criteria that are described in the "Standard values" section.

For this, the examiner determines the respective Wall thickness in millimeters and compare them to the Standard values. A slight magnification is indicated with a +, greater with several. If the doctor has measured both atria and ventricles, the examination follows Function of the chambers. Depends on the Pumping power the ventricle is rated in different grades. These could be, for example:

  • normal
  • somewhat reduced
  • moderately reduced
  • greatly reduced.

The contraction of the individual wall sections of the cavities is then observed and checked for irregularities. Even minor asynchronicities, which occur, for example, in the case of problems with the conduction of excitation or heart attacks, can greatly reduce the heart's pumping capacity. In addition, the doctor pays attention to any hypokinesis, that is, a contraction that is too slow, or even akinesis, i.e. an inability of the myocardium to contract. Causes for this could also be damage to the stimulus transmission system or circulatory disorders of the heart muscle.

On the Checking the chamber function finally follows the Assessment of the individual flaps. First, the appearance is assessed. Visible Enlargements, Calcifications, Cracks etc. are documented by the doctor. In addition, the movement of the cap is observed and noticeable restrictions written down. This is followed by the evaluation of the valve function. Basically, a distinction is made between two different types of valve dysfunction Stenosis and on the other hand the insufficiency. In the case of a stenosis, the valve does not open properly so that the heart has to pump against increased pressure. In the case of valve insufficiency, it does not close sufficiently so that blood can flow back into the upstream cavity and this leads to volume loading. During echocardiography, the doctor pays particular attention to such valve defects and diagnoses them depending on their severity. For example, a mild insufficiency can be rated with the word "minor", while a severe insufficiency is described as "severe".

indication

Echocardiography becomes a diagnosis numerous diseases of the heart, as well as partly for supporting diagnostics applied to diseases outside of the heart. Since echocardiography is a very meaningful And thereby inexpensive, such as nationwide The available method is echocardiography very often Application. In addition, it is a low risk process, the little burdensome is for the patient.

Common indications for performing an echocardiography (TTE or TEE) include these Occurrence of symptoms that indicate a heart diseasesuch as shortness of breath, pain or a racing heart. Even with the assumption of one congenital heart defect or an echocardiography is performed to check for a known congenital heart defect.

Furthermore, for Diagnosis of a heart attack or echocardiography can be performed after a heart attack. Even in patients with an abnormal one Heart murmur, in which the suspicion of a Valvular heart disease suggests, echocardiography should be performed. Patients who have received a heart valve prosthesis due to a disease of the heart valves are also examined using echocardiography to document the successful replacement.

Echocardiography can also provide clues Cardiac arrhythmias deliver. Another indication is the suspicion of one inflammatory disease of the heart (for example Endocarditis). In addition, echocardiography can be used Thrombi (Blood clots), as well as very rarely tumors be detected in the heart. Furthermore are Diseases of the pericardium (Pericardium), which surrounds the heart muscle, important indications. These include the Pericardial effusion (Accumulation of fluid between the heart muscle and pericardium) and the Pericarditis (Inflammation of the pericardium).

Particularly in transesophageal echocardiography (TEE), structures outside the heart, such as the Main artery (aorta) be assessed. Therefore, there is another indication here, the suspicion of a pathologically altered aorta. Another indication for performing an echocardiography (TTE or TEE) is certain diseases of the lungs, such as a Pulmonary embolism or a collapsed lung (Pneumothorax). In pulmonary embolism a blood clot blocks the blood vessels leading to the lungscausing the blood to back up in front of the heart. This is visible in the echocardiography and can thus be recognized at an early stage.
Especially with stress echocardiography ("stress echo") is one Circulatory disorder of the heart muscle, so the suspicion of coronary artery disease (CHD), the most common indication.

Please also read our page Diagnosis of coronary artery disease.

Further investigations

The creation of an EKG is also useful.

In addition to the various forms of echocardiography, such as transthoracic echocardiography (TTE), transesophageal echocardiography (TEE) and stress echocardiography ("stress echo"), a few other methods are available for examining the heart, all of which provide initial indications of cardiac diseases can. Some of these tests are done before an echocardiography is done. If a patient comes to the doctor with symptoms that indicate a heart disease, they will usually find one first detailed questioning of the patient by the doctor (anamnesis). The doctor asks, among other things, the exact symptoms of the patient (e.g. shortness of breath, pain, palpitations) and whether the patient or his family is already aware of cardiac diseases.

In most cases, the anamnesis is followed by one physical examination on. This includes a close examination of the undressed chest (inspection), palpation of the pulse (Palpation) and listening to the heart with a stethoscope (Auscultation). The auscultation can for example point to Valvular heart disease (abnormal heart murmur) or a Heart failure (quietly Heart sounds) deliver.

This is usually followed by an Electrocardiography (EKG) with which potentially suspicious findings from the physical examination can be corroborated or eliminated. In electrocardiography (EKG), six or twelve electrodes are stuck to the patient's chest electrical activity of the heart record. The electrical activity of the heart can, similar to echocardiography, at rest or under stress as part of a Exercise EKGs to be recorded. Furthermore, there is the possibility, for example, of a suspected cardiac arrhythmia Long-term echocardiography (Long-term ECG) over 24 hours. With the help of electrocardiography, among other things, the Heart rate, the heart rhythm, or the Spread of excitation can be assessed via the heart muscle and thus also provide information on various diseases.

The next step is the imaging diagnostics, to which in addition to echocardiography there is also a X-ray, one Computed tomography (CT), or a Magnetic resonance imaging (MRI) of the chest. The procedures mentioned make the heart visible and can provide information about the size of the heart, the thickness of the heart muscle or changes in the heart valves, among other things.

With another investigation, the Myocardial perfusion scintigraphy can especially the Blood flow to the heart muscles be assessed. In addition, invasive procedures for examining the heart are also used. An important process is that Cardiac catheter examination. During the cardiac catheter examination, a specially shaped and flexible plastic tube is inserted under local anesthesia into a vein (this is called a right catheter) or in a artery (this is called a left catheter) inserted into the patient's groin and advanced over the vessel to the heart. With the help of the plastic hose, on the one hand, the Pressures in the atrium and in the ventricle are measured and on the other hand via the administration of contrast medium via the plastic tube into the vascular system Blood flow to the coronary arteries be judged very well.
Can be found during the cardiac catheter examination constricted cardiac arteries, can do this in the same session be expandedto prevent a heart attack from developing.

Finally, as part of a cardiac catheter examination, a Myocardial biopsy respectively. This is understood to mean the Removal of heart muscle tissue from the inner layer of the heart. The myocardial biopsy is particularly used Suspected inflammatory diseases of the heart or when suspected congenital or acquired heart muscle disease carried out. For special indications, there is also a simple examination of the blood an important role. For example, if you have a heart attack, certain heart attack markers such as Troponin or creatinine kinase be increased in the blood and thus the suspicion of a heart attack can be confirmed by these parameters.

Summary

The ultrasound scan of the heart (Echocardiography) has played an important role in today's diagnosis of heart disease. The largely non-invasive Possibility of displaying the heart function in the "echo“May like numerous heart diseases Flap failure, Bottlenecks (Stenoses), Short circuits between the ventricles or atria (Shunts) and wall movement disorders.

With the help of minimally invasive transesophageal echocardiography (TEA) the cardiac function of obese patients or patients with lung disease can also be displayed, whereas classic transthoracic echocardiography is no longer meaningful. The various settings on the ultrasound device can be used to display the blood flow, short circuits or valve insufficiencies in color.
Through the M-mode it is possible to visualize the movements of the valves and the left ventricle on a horizontal one-dimensional line. With these numerous possibilities and the minimally invasive examination method, echocardiography has become an indispensable part of the diagnosis of heart diseases.