Echocardiogram

Excerpt

Echocardiography is the use of ultrasound to evaluate the structural components of the heart in a minimally invasive strategy. Although, prior to the invention of today's routinely used 2-dimensional echocardiography, there was motion-based (M-mode) echocardiography. In 1953, Inge Edler, regarded as the father of echocardiography, first described M-mode technology, which began the era of diagnostic noninvasive echocardiography. M-Mode echocardiography was the combination of amplitude-based (A-mode) ultrasonography with Brightness-based (B-mode) techniques, which allowed the addition of a "time" dimension when the B-mode was swept across the oscilloscope; however this was not a picture, per se, but how structures evolved through the cardiac cycle. This was the primary technology until two-dimensional (2D) ultrasonography was developed over the next decades. In 1973, S.L. Johnson developed 2D ultrasonography and doppler technology, which ultimately allowed physicians to detect blood flow in vessels, and, in 1979, Holen and Hatle found that by using the Bernoulli equation they could detect pressure gradients. The combination of all these technologies is the echocardiography that is commonly used every day in today's medical profession.

The most commonly used technique among these is transthoracic echocardiography (TTE). This allows the clinician to obtain real-time sizes, structure, and function of the heart during the cardiac cycle. Another useful and important use of these methods is stress echocardiography. Stress echocardiography is the combination of standard transthoracic echocardiography and either pharmacological or physical stress to the cardiac structures to assess wall motion abnormalities. Physical stresses may include running on a treadmill, and pharmacological stress, including medications. When higher resolution imaging of cardiac structures, including valves, is required, transesophageal echocardiography (TEE) is considered. TEE is more invasive than standard TTE, as it requires the insertion of a probe into the patient's esophagus to obtain images not hindered by the patient's chest wall, including; muscle, tissue, and bone. When more accurate and even higher-resolution imaging is needed, during intracardiac procedures, intracardiac echocardiography (ICE) is an option that can be considered.

Echocardiography is a low cost, at times minimally invasive, and readily available test that can provide information that can change the treatment course, and in some cases, provide real-time life-saving information. Many of the clinical uses of echocardiography are multidisciplinary in practice, and the overlap between the different utilities of echocardiogram is large. The addition of contrast to echocardiography, or the addition of strain to TTE are all examples of combinations of these utilities. The utilization of echocardiography is vast and can be applied in a variety of ways and a wide range of situations, and these forms will be discussed in detail.