Dobutamine Stress Echocardiography

Overview

What is a Dobutamine Stress Echocardiogram?

Echocardiography is a noninvasive (the skin is not pierced) procedure used to assess the heart's function and structures. A transducer (like a microphone) sends out ultrasonic sound waves at a frequency too high to be heard. When the transducer is placed on your chest at certain locations and angles, the ultrasonic sound waves move through the skin and other body tissues to the heart tissues, where the waves echo off of the heart structures. The transducer picks up the reflected waves and sends them to a computer. The computer interprets the echoes into an image of the heart walls and valves.

The physician may request an echo to be performed after exercise to evaluate the effects of exercise on the heart. However, some people may be unable to exercise on a treadmill or stationary bicycle due to conditions such as the following:

• recent heart attack
• severe hypertension (high blood pressure)
• severe arrhythmias (heart rate is too fast, too slow, or too irregular)
• severe leg pain with exercise due to poor blood flow in the legs
• severe asthma, emphysema, or chronic obstructive pulmonary disease
• aneurysm
• pericarditis

If any of the above reasons, or other reasons, are present to prevent a patient from exercising on a treadmill or bicycle, it is possible to mimic exercise by injecting an intravenous (IV) medication called dobutamine. Dobutamine causes the heart to beat faster as it does during exercise.

A dobutamine stress echocardiogram can utilize one or more of four special types of echocardiography, as listed below:

1. M-Mode echocardiography
   This, the simplest type of echocardiography, produces an image that is similar to a tracing rather than an actual picture of heart structures. M-mode echo is useful for measuring heart structures, such as the heart's pumping chambers, the size of the heart itself, and the thickness of the heart walls.
   
   
2. Doppler echocardiography
   This Doppler technique is used to measure and assess the flow of blood through the heart's chambers and valves. The amount of blood pumped out with each beat is an indication of the heart's functioning. Also, Doppler can detect abnormal blood flow within the heart, which can indicate a problem with one or more of the heart's four valves or with the heart's walls.
   
   
3. Color Doppler
   Color Doppler is an enhanced form of Doppler echocardiography. With color Doppler, different colors are used to designate the direction of blood flow. This simplifies the interpretation of the Doppler technique.
   
   
4. 2-D (2-dimensional) echocardiography
   This technique is used to "see" the actual structures and motion of the heart structures. A 2-D echo view appears cone-shaped on the monitor, and the real-time motion of the heart's structures can be observed. This enables the physician to see the various heart structures at work and evaluate them.
   

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