(TTE) Transthoracic echocardiography is a common type of cardiac ultrasound and is used to evaluate the size and function of the heart.

Indications:
TTE requires no sedation or special patient preparation. After the application of ECG electrodes and ultrasound couplant, the probe is maneuvered over the chest in the area adjacent to the breast bone and under the left breast, to provide the different views of the heart. Usually the images will be obtained lying relaxed on the left side. Other views can be sampled lying on the back with the knees bent, or sitting in an upright position.

See also Bicycle Stress Echocardiography and Transesophageal Echocardiography.

Stress echocardiograms are used for detection of coronary artery disease, or to determine the cardiac performance. Stress echocardiograms are less performed to evaluate pulmonary artery pressures, pulmonary hypertension or the significance of valvular heart disease.
Stress increases the degree to which the heart contracts. After a myocardial infarction there will be a region of the heart muscle that contracts abnormal at rest. This area may worsen with stress. A coronary artery blockage most often do not impairs the function of the heart at rest. With stress, a region of the heart does not receive enough blood to work effectively and wall motion abnormalities occur. The echocardiographer compares rest and exercise and can determine the presence and severity of a coronary artery blockage.

Stress echocardiograms involve:
A bicycle stress echocardiogram involves transthoracic echocardiography performed at the rest baseline and after or during different stages of physical exercise.
A dobutamine stress echocardiography uses the drug dobutamine instead physical exercise.
Transthoracic echocardiograms are routinely performed during stress and rest.
Cardiovascular stress represents a minimal risk to the patient.

See also Transesophageal Echocardiography, Echocardiography, M-Mode, Curved Transducer, Doppler Ultrasound, History of Ultrasound and History of Ultrasound Contrast Agents.

Dobutamine stress echocardiography is a variation of exercise echocardiography to unmask coronary artery blockages. During this test, the heart is stressed by infusing dobutamine. Dobutamine is commonly used to treat patients with low blood pressure, to improve circulation and as a diagnostic testing agent. Dobutamine increases the heart rate and blood pressure and the degree to which the heart contracts. It therefore mimics the effects of exercise for patients who are unable to exercise to a sufficient degree.
The examination starts with the resting transthoracic echocardiogram. After that, dobutamine is infused at a low dose. Following, the dose is increased every three minutes to increase the heart rate and cardiac contractions. At each of these three-minute stages, the heart is scanned using transthoracic echocardiography. An electrocardiogram has to be continuously recorded and blood pressure automatically checked every three minutes.
Disconcerting and stress-related sensations of the patient is to expect during infusion of dobutamine and does not represent any harmful effect. As soon as the infusion is completed, it is discontinued and usually within five to ten minutes the heart rate and blood pressure will return to the levels before starting the exam. Only qualified staff with specific training should perform this test. As for all types of cardiovascular stress testing, all of the necessary equipment and medicines to treat complications must be available in the stress testing room.

Echocardiography is the ultrasound examination of the heart. Depending on the used ultrasound system, echocardiograms can be two-dimensional slices or 3D real-time images of the heart. Based on the ultrasound principles the direction and speed of blood flow can be utilized e.g., to diagnose a leaking or stenosed valve or to identify intracardiac shunts.

Different types of echocardiography:
The transthoracic echocardiogram (images are taken through the chest wall) is a non-invasive, highly accurate and quick assessment of the overall health of the heart.
A more invasive method is to insert a specialized scope containing an echocardiography transducer (TEE probe) into the esophagus, and record images from there. The advantages are clearer images, since the transducer is closer to the heart.
Contrast echocardiogram (CE) is already a valuable tool to delineate endocardial borders, direct invasive procedures, detect intracardiac shunts, assess myocardial perfusion and viability, and quantify coronary flow reserve and blood volumes (see also hemoglobin). The mechanism of microbubble CE is based on the physical principles of rarefaction and compression, leading to volume pulsations of microbubbles, and it is this change that results in CE signal.
Stress echocardiograms are echocardiography exams used for detection of coronary artery disease.

See also Diastole, Bicycle Stress Echocardiography, Resistive Index, and M-Mode Echocardiography.

M-mode (Motion-mode) ultrasound shows the motion of cardiac structures. M-mode echocardiography records the amplitude and rate of motion of a moving structure in real time by repeatedly measuring the distance of the object from the single transducer at a given moment. The single sound beam is transmitted and reflected signals are displayed as dots of varying intensities, creating lines across the screen. It yields a one-dimensional image, sometimes called an 'ice pick' view of the heart.
M-mode echocardiography is used to detect valvulopathies (calcifications, etc.) and cardiomyopathies (dyskinesis, aneurysm, etc.).

See also Bicycle Stress Echocardiography, Transthoracic Echocardiography, and Transesophageal Echocardiography.