Dobutamine Stress Echocardiography

Dobutamine Stress Echocardiography is a noninvasive (the skin is not pierced) procedure used to assess the heart's function and structures. 

This procedure is done as a substitute for an exercise echo, because some people may be unable to exercise on a treadmill or stationary bicycle due to conditions such as: 

• 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
• (COPD)
• aneurysm 
• pericarditis 

If any of the above reasons, or other reasons, are present which 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 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 preparation for the DSE procedure is similar to that of the basic echo. In addition, an IV line will be started in your hand or arm, and a blood pressure cuff will be placed on your arm. A baseline assessment of your heart rate and blood pressure will be done. 

The echocardiography technician will apply warmed gel to your chest. Then he/she will position the transducer on your chest and use a small amount of pressure to obtain the desired image. The dobutamine infusion will begin at a rate determined by your weight. The rate of the infusion will be increased every three minutes until you have reached your target heart rate (determined by the physician based on your age and physical condition) or until the maximum dose of dobutamine has been reached. After the dobutamine is started and after each increase in the dobutamine rate, your blood pressure will be checked, an EKG tracing will be made, and echo images will be obtained. The technician will move the transducer around on your chest so that all areas and structures of your heart can be observed. During the test, the different echo techniques described above (M-mode, 2-D, Doppler, and color Doppler) may be used. 

You will not be aware of the different techniques except that during the Doppler or color Doppler, you may hear a "whoosh-whoosh" sound. This whooshing sound is your blood moving through the heart. 

Once your have reached your target heart rate or the maximum amount of the dobutamine, the medication will be stopped. Your heart rate, blood pressure, EKG, and echo will continue to be monitored for 10-15 minutes until they have returned to the baseline state, or close to it. Once all the images have been taken, the technician will wipe the gel from your chest, remove the EKG electrode pads, take out the IV line, and assist you to dress, if necessary. 

Once the procedure has been completed, you will be able to leave and return to your previous activities, unless your physician instructs you differently. A DSE usually takes about 1-1˝ hours to perform. However, factors such as schedule delays, emergencies, and other factors may delay the start of your procedure or prolong the length of it. 

Some reasons for having a dobutamine stress echo include, but are not limited to, the following: 

• to assess the heart's function and structure 
• to assess limits for safe exercise in patients who are entering a cardiac rehabilitation program and/or those who are recovering from a cardiac event such as heart attack or heart surgery
• to assess blood pressure reaction during stress testing 
• to assess stress or exercise tolerance in patients with known or suspected coronary artery disease 
• to assess cardiac status in patients who are about to undergo surgery