First-pass radionuclide studies are performed using a radiopharmaceutical agent to check for blood flow through the great vessels and after vessel surgery; it is useful in the determination of both right and left ventricular ejection fractions. Immediately after the radionuclide agent injection, the camera traces the flow of the radiopharmaceutical agent in its “first pass” through the cardiac chambers in multiple rapid images. Results of the study may help in planning more appropriate patient management of cardiac conditions.
First-pass radionuclide studies are also useful in examining heart chamber disorders, especially left-to-right and right-to-left shunts. Children are commonly candidates for this procedure. Indications for pediatric patients include evaluation for congenital heart disease, transposition of the great vessels, and atrial or ventricular septal defects and quantitative assessment of valvular regurgitation. In neonates, the cardiac flow study can be used in conjunction with computer software for quantitative assessments. These quantitative values are useful in determining the degree of cardiac shunting with septal defects in the atria or ventricles.
Use a three-way stopcock with saline flush for radionuclide agent injection into the jugular vein or the antecubital fossa. For a shunt evaluation, inject the radionuclide agent into the external jugular vein to ensure a compact bolus.
Have the patient lie supine with the head slightly raised.
Although the total patient time is approximately 20–30 minutes; the actual imaging time is only 5 minutes.
Perform a resting MUGA scan with a shunt study.
See Chapter 1 guidelines for safe, effective, informed intratest care.
With pediatric patients, it is important that the child not cry during the study because this disrupts the flow of the radiopharmaceutical and negates the results of the test.
Abnormal first-pass ejection fraction values are associated with:
Heart failure
Change in ventricular function due to infarction
Persistent arrhythmias from poor ventricular function
Regurgitation due to valvular disease
Ventricular aneurysm formation
Abnormal heart shunts reveal:
Left-to-right shunt
Right-to-left shunt
Mean pulmonary transit time
Tetralogy of Fallot
Pretest Patient Care
Explain the purpose, procedure, benefits, and risks. An IV line is required.
Follow guidelines in Chapter 1 for safe, effective, informed pretest care.
Refer to standard nuclear scan pretest precautions.
Obtain a signed, witnessed consent form if stress testing is to be done.
Posttest Patient Care
Review test results; report and record findings. Modify the nursing care plan as needed. Monitor injection site and counsel patient appropriately.
Refer to standard nuclear scan posttest precautions.
Follow guidelines in Chapter 1 guidelines for safe, effective, informed posttest care.