The Cardiac Cath learning module is made
up of 6 parts or sections. You may navigate through the
pages by clicking on the green
arrows or numbers (above), the specific questions (below) or the gray menu items on the left.
The x-ray camera sits on top of the patient's chest, while the x-ray beam is
delivered from underneath the table. A movie camera is attached to the tube to
record images on a 35mm film. Images are also noted "live" on the monitor and
are also recorded on a computer disk drive and / or a video tape. The x-ray tube
is rotated around the patient (side-to-side, and also towards and away from the
head), as shown below. By taking pictures from different angles, the
cardiologist can inspect blockages from several points of view. This increases
the accuracy of assessing the clinical importance and severity of a blockage. It
also helps determine the patient's candidacy for angioplasty, stenting, surgery,
medical treatment, etc.
Cardiac cath is usually carried
out in a hospital setting but may also be performed in some clinics or in a
mobile laboratory. The patient lies on a table with an attached handle. This
handle allows the cardiologist to move the table and also to rotate the x-ray
tube. A plastic covered shield is present between the cardiologist and the
patient to cut down on radiation. The top portion of the shield is transparent
so that the cardiologist can see the patient through it. The cath lab is kept
cool. Otherwise, heat would damage the sensitive electronic and x-ray
The animation (left) shows a model of the cardiac cath table. Click on the VCR-type "play" button to "walk-around" the cath table and equipment.
The picture on the left (above) shows what the image Intensifier (x-ray tube) and camera would "see" as it
moves around the patient's chest. The rotation of the tube helps to prevent
branches from overlapping each other and obscuring a lockage.
What is Experienced in the Cath Lab
The patient may have a feeling similar to a bee sting when the groin is
"numbed" with local anesthesia. A sticking sensation is also felt when the
needle is inserted. This is very tolerable. The cardiologist should be notified
if there is a lot of discomfort or pain. Additional local anesthesia or more
sedatives will usually alleviate the discomfort.
The patient will be lying on a relatively firm table and the room will be
cool. During the procedure, the patient may be asked to hold his / her breath or
cough. The former improves the quality of the x-ray movies when the diaphragm
(muscle partition between the chest and abdomen) partially obscures a certain
portion of the coronary artery. A deep breath improves the picture.
The contrast material may occasionally cause the heart to slow down. Coughing
helps clear the contrast from the coronary artery. Coughing may also help
correct certain types of abnormal heart rhythm.
The patient should be able to watch most of the study on the TV monitor. The
cardiologist may explain the findings as the procedure is carried out.
It is important to remember that the blue or green sheets covering the
patient are sterile. Hands should be kept by the side and not placed on top of
the sheet. The patient should not reach for the groin because it will
contaminate the catheter. If a pillow needs to be rearranged or a cheek
scratched, the staff will be happy to help.
Fleeting chest discomfort may also be felt during some coronary artery
injections. A transient "hot flash" is usually felt when pictures of the Left Ventricle
(LV) are taken, as shown below. This sensation generally clears up
in less than 30 seconds.
Angiogram of the Left Ventricle
The coronary arteries are relatively small and can be easily filled by injecting around 5 to 8 cc or ml of contrast or "dye" , with the help of a hand-held syringe. X-ray movies are usually taken when the arteries are filled with contrast. The left ventricle (LV or the major pumping chamber of the heart), on the other hand, is larger and requires more contrast to fill it. To allow proper visualization of the LV, nearly 30 or more cc of contrast is injected over 2 to 3 seconds with the use of a power injector.
Angiogram of the left ventricle
The cardiac cath Tech helps load the power injector with contrast material or "dye". When instructed to do so by the cardiologist, button is pushed and the contrast is injected into the left ventricle through the catheter (which has its tip positioned in that chamber of the heart.
.Click on the play button to view this, and the subsequent movies.
The x-ray pictures are taken by a movie camera. It will sound like a hum, motor or
loud sewing machine when pictures are being recorded.
Pulling the Sheath from the Artery
Removal of the Sheath
After completion of the
procedure (which usually takes 10 to 15 minutes), the patient is taken to the
recovery room, where the sheath is removed from the groin. Firm pressure is
applied for approximately 10-15 minutes (the time may vary) to stop/prevent
bleeding from the small needle hole. In many cases, hand pressure may be substituted with, or followed by, the use of a compression device.
Removal of the sheath and application of pressure in the area, to prevent bleeding, is shown above. A dressing is then placed on the groin and a
sand bag or ice bag may be used on top of the dressing. The patient will have to
lie flat for three to four hours. It is important to not sit-up, bend the leg or
strain during the time of bed rest. However, the head of the bed may be raised
slightly and the feet can be moved to a small degree. Removal of the sheath is delayed if heparin or other "blood thinners" are used during the procedure. The sheath is pulled when a blood test indicates that it is safe to do so.
If there is a warm or wet sensation around the catheter insertion site or if
there is blood on the dressing, pressure needs to be applied at the site and the
nurse called immediately. If there is bleeding, there is no need for panic.
Additional pressure will almost always take care of the problem.
If there is a need to sneeze or cough, light finger pressure must be applied
right above the catheter insertion point. A nurse will provide instructions.
This will reduce the risk of bleeding.
If the arm is used during the procedure, pressure will be applied over the
Some cardiac centers use closure devices in the cath lab. In such cases, the
hole is sealed when the patient leaves the lab and application of pressure is
not usually needed. This increases the cost of the procedure and carries a very
small and acceptable complication rate.
When the anesthesia wears off, the patient may experience soreness. The nurse
can provide pain medication to take care of this problem. The blood pressure and
pulse rate are monitored during the recovery phase.
The nurse needs to be notified if there are any problems with dizziness,
lightheadedness or chest discomfort. Nausea may occasionally occur and is
usually resolved with medications. The contrast material acts as a diuretic or
"water pill." Also, a lot of intravenous fluids are used. This combination will
cause the patient to produce large amounts of urine. Some patients may not be
able to void in the flat or supine position. If the bladder gets distended and
causes discomfort, a tube may be temporarily placed in the bladder.
After bed rest is completed, the patient is made to sit up and then stand
with assistance. After further observation, if there are no problems or
bleeding, the patient is discharged