Dobutamine Stress Testing:

We may prescribe a dobutamine stress testing for any patient who is unable to exercise or may have other conditions that pose a contraindication to treadmill exercise testing or pharmacologic exercise testing with Adenosine™ or Persantine™ (lung disease, arthritis or severe peripheral vascular disease).

Dobutamine is a short-acting intravenous agent that acts to increase your heart rate and increase the force of your heart- muscle contraction.
Indications

A stress test is designed to look for the presence of “ischemia”. Ischemia is a relative deficit of blood flow (usually related to a blocked coronary artery) resulting in a relative deprivation of the oxygen and nutrients that the heart muscle (myocardium) may require. The stress test may be requested to:

You should wear loose-fitting, comfortable clothing.

Do not eat or smoke for six hours prior to your scheduled test time. You may have sips of water at any time. If you have diabetes, you should check with your family physician or call the , regarding any diet restriction, as well as special instructions regarding your blood sugar medicine or insulin regimen.

Consult with your family physician or call the , regarding whether certain medications should be taken before or held until after the test. Certain medicine (most commonly, beta-blockers) may interfere with the effectiveness of the study.

Upon arrival to the Scranton Heart Institute, P.C., or hospital, an intravenous line (IV) will be inserted into your arm to infuse the dobutamine, and provide the radioisotope that will be given for nuclear imaging. You will lie comfortably on a special examination table. Electrocardiogram (ECG) electrodes will be placed on your chest and connected to the stress-ECG machine by lead wires or cables to continuously record your electrocardiographic information during the testing procedure. A blood pressure cuff will be applied to your arm so we can record your blood pressure during the test.

The procedure will be performed under the direction of a Dr. Stafford M. Smith (Board-Certified Cardiologist). An exercise technician and/or exercise physiologist, nurse, and nuclear medicine technologist may also be present for the procedure. For individuals scheduled to have dobutamine cardiac stress-ultrasound imaging, a sonographer (ultrasound imaging specialist) will take ultrasound images of your heart both rest, and after specific intervals during the study. Your heart rate and rhythm, EKG, and blood pressure will be monitored continuously throughout the testing phase.

The dobutamine medication will be given to you initially slowly intravenously. This dose will be gradually incrementally increased over a total of up-to four stages (usually two to three minutes each), depending on the duration necessary to achieve a satisfactory heart rate that will render the study valid (“target heart-rate”). After reaching “target heart-rate”, the dobutamine infusion must be continued for an additional minute or two, to allow time to provide for adequate circulation and distribution of the radioisotope, or allow acquisition of ultrasound images at or beyond the target heart rate. Some patients may require the administration of supplemental medication(s) [atropine] in order for the heart rate to get up to “target”.

Some patients experience specific symptoms, such as chest or arm pain, shortness of breath, palpitations, and/or lightheadedness during the study. These symptoms are usually limited to the period of time during which the heart rate is accelerated. If you experience any of these or other symptoms, please inform the individuals that are supervising your test.

Your normal (slower) heart rhythm will return to baseline within a few minutes after the test is completed. A few patients may receive therapeutic “reversing medication” for the dobutamine (usually metoprolol of esmolol) to speed up the return of a normal heart rate and blood pressure. Most individuals find that they are feeling “back-to-normal” within five-to-ten minutes after the termination of the dobutamine infusion. When your heart rate and blood pressure have returned to baseline, you will be disconnected from the ECG machine and given an opportunity to clean up. If you are having nuclear imaging performed in association with your study, you will be required to spend two separate imaging periods under a Gamma camera (usually less than twenty minutes each); one before your dobutamine infusion, and one shortly after your dobutamine infusion.

Many patients are concerned about receiving diagnostic radioactive isotopes. The agents we use have been given for many years without any adverse effect from the radioactivity ever being reported. The patient can be assured that the smallest possible amount of radioactivity to do the test is used. The amount of radioactivity received is approximately equivalent to 1-2 years of natural (background) radiation, or the equivalent of one or two chest x-rays. No special precautions are needed after the test.

Patients who are pregnant, might be pregnant, or are nursing, should not receive radioactivity, and should inform our staff of their status prior to their test, so that alternative arrangements can be made.

The ECG tracings and ultrasound or nuclear images will be given to your cardiologist (Stafford M. Smith, M.D.) to interpret usually within 24-48 hours. An official report will be generated and sent immediately to your family physician, referring physician, or other health care provider. If you will require extra copies of your reports sent to other physicians or health care providers, please inform our staff of exactly how many copies you will need and who they are to be sent to.  You should have available the correct addresses and telephone numbers [including the FAX number(s)] for these individuals at the time of your request.

As the study is designed to detect ischemia; for any finding of ischemia that is at-least “small” in size, you will be contacted directly, shortly after the study report has been generated. Please note that additional testing (such as cardiac catheterization) may be recommended for such a finding.

Cardiac imaging (both nuclear and ultrasound) may disclose other anomalies that technically cannot be interpreted as “normal”, but will be reported to your physician. These studies are not “perfect” and in addition, can be subject to imaging errors and artifacts. You may call the or your family physician’s office to obtain the official results of the study. If you feel that it is necessary to discuss the meaning of your testing results in more detail, please make an appointment to discuss the significance of your testing results with our staff physician.  You may also wish to discuss the results further with your primary care physician (and he or she with you).