Transthoracic echocardiogram
Encyclopedia
A standard echocardiogram is also known as a transthoracic echocardiogram (TTE), or cardiac ultrasound. In this case, the echocardiography transducer (or probe) is placed on the chest wall (or thorax
Thoracic cavity
The thoracic cavity is the chamber of the human body that is protected by the thoracic wall ....

) of the subject, and images are taken through the chest wall. This is a non-invasive, highly accurate and quick assessment of the overall health of the heart. A cardiologist or cardiac physiologist can quickly assess a patient's heart valves and degree of heart muscle contraction (an indicator of the ejection fraction
Ejection fraction
In cardiovascular physiology, ejection fraction is the fraction of Blood pumped out of the Right Ventricle of the heart to the Pulmonary Circulation and Left Ventricle of the heart to the Systemic Circulation with each Heart beat or Cardiac cycle...

). The images are displayed on a monitor, and are recorded either by videotape (analog) or by digital techniques.
An echocardiogram can be used to evaluate all four chambers of the heart. It can determine strength of the heart, the condition of the heart valves, the lining of the heart (the pericardium), and the aorta. It can be used to detect a heart attack, enlargement or hypertrophy of the heart, infiltration of the heart with an abnormal substance. Weakness of the heart, cardiac tumors, and a variety of other findings can be diagnosed with an echocardiogram. With advanced measurements of the movement of the tissue with time (tissue doppler), it can measure diastolic function, fluid status, and dys-synchrony.

The TTE is highly accurate for identifying vegetations (masses consisting of a mixture of bacteria and blood clots), but the accuracy can be reduced in up to 20% of adults because of obesity
Obesity
Obesity is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems...

, chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease
Chronic obstructive pulmonary disease , also known as chronic obstructive lung disease , chronic obstructive airway disease , chronic airflow limitation and chronic obstructive respiratory disease , is the co-occurrence of chronic bronchitis and emphysema, a pair of commonly co-existing diseases...

, chest-wall deformities, or otherwise technically difficult patients. TTE in adults is also of limited use for the structures at the back of the heart, such as the left atrial appendage. Transesophageal echocardiography may be more accurate than TTE because it excludes the variables previously mentioned and allows closer visualization of common sites for vegetations and other abnormalities. Transesophageal echocardiography also affords better visualization of prosthetic heart valves.

"Bubble contrast TTE" involves the injection of agitated saline into a vein, followed by an echocardiographic study. The bubbles are initially detected in the right atrium and right ventricle. If bubbles appear in the left heart, this may indicate a shunt, such as a patent foramen ovale, atrial septal defect
Atrial septal defect
Atrial septal defect is a form of congenital heart defect that enables blood flow between the left and right atria via the interatrial septum. The interatrial septum is the tissue that divides the right and left atria...

, ventricular septal defect
Ventricular septal defect
A ventricular septal defect is a defect in the ventricular septum, the wall dividing the left and right ventricles of the heart.The ventricular septum consists of an inferior muscular and superior membranous portion and is extensively innervated with conducting cardiomyocytes.The membranous...

 or arteriovenous malformation
Arteriovenous malformation
Arteriovenous malformation or AVM is an abnormal connection between veins and arteries, usually congenital. This pathology is widely known because of its occurrence in the central nervous system, but can appear in any location. An arteriovenous malformation is a vascular anomaly. It is a...

s in the lungs.
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