Cardiac Radiography
Norm of Cardiac Radiography
Normal size, shape, and appearance of the heart and lungs. Posteroanterior and lateral views should demonstrate no enlargement or bulging of the right ventricle, right ventricular outflow tract, left ventricle, or pulmonary veins, and no aortic abnormalities. The left cardiac border should be convex, rather than straight.
Usage of Cardiac Radiography
Congestive heart failure, abnormalities of the aortic arch (calcifications); some aneurysms; transposition; evaluation of the appearance, size, and shape of the heart and lungs; and verification of invasive line placement and position.
Description of Cardiac Radiography
A radiograph of the thoracic area and subsequent examination of the film for abnormalities. The procedure of choice is that carried out in the radiology department with the client in a standing or erect sitting position for posteroanterior and left-lateral views of the chest. The posteroanterior position provides the most realistic view of cardiac size and shape. In this position, the heart is closer to the film than in an anteroposterior view, resulting in less distortion of cardiac size and shape as a result of shadows created by distance.
Professional Considerations of Cardiac Radiography
Consent form NOT required.
Risks
Hypotension while holding breath; fetal damage during first trimester of pregnancy.
Contraindications
Assess for contraindications to performing the Valsalva maneuver (recent myocardial infarction, bradycardia). If these conditions are present, teach the client how to hold the breath without bearing down.
Precautions
During pregnancy, risks of cumulative radiation exposure to the fetus from this and other previous or future imaging studies must be weighed against the benefits of the procedure. Although formal limits for client exposure are relative to this risk to benefit comparison, the United States Nuclear Regulatory Commission requires that the cumulative dose equivalent to an embryo/fetus from occupational exposure not exceed 0.5 rem (5 mSv). Radiation dosage to the fetus is proportional to the distance of the anatomy studied from the abdomen and decreases as pregnancy progresses. For pregnant clients, consult the radiologist/radiology department to obtain estimated fetal radiation exposure from this procedure.
Preparation
- Remove radiopaque objects above the waist such as jewelry and clothing with snaps. Also remove electrocardiographic patches with snaps when not contraindicated.
- The abdomen and pelvis should be shielded by lead during pregnancy.
Procedure
- For the posteroanterior view, position the client standing or sitting erect with arms held slightly out from the sides, chest expanded, and shoulders pressed forward. The radiographic film is placed against the anterior chest.
- For left lateral views, the client stands with his or her arms elevated from the shoulders and forearms resting on the arm of the radiographic equipment if necessary. The radiographic film is placed against the left side of the chest.
- The client must take a deep breath and hold it while the radiograph is taken.
- For clients unable to stand or sit erect, an anteroposterior view is taken with the client sitting in as high a Fowler's position as possible and the radiographic plate positioned behind the back and chest.
Postprocedure Care
- Replace the electrocardiographic monitoring patches and leads.
Client and Family Teaching
- You must breathe in and hold your breath and lie very still during the procedure.
Factors That Affect Results
- Radiopaque objects such as jewelry and wires create shadows on the film.
- The cardiac size and shape appear larger in an anteroposterior radiograph than in a posteroanterior radiograph.
- Cardiopulmonary congestion requires an increase in exposure.
- Inadequate films result when the client is unable to hold a deep inspiration during exposure.
- Movement obscures the clarity of the picture.
- Thoracic deformity such as scoliosis affects radiographic interpretation.
Other Data
- Although contraindicated during the first trimester, this is the procedure of choice when necessitated during pregnancy because the amount of radiation delivered is up to 20 times less than that of the nuclear medicine cardiac series.
