The Cardio Pulmonary Department also performs a variety of Cardiac Diagnostic procedures, including EKGs . 24 hour Holter monitoring and Cardiac Event monitoring. 24-hour Holter monitors and Cardiac Event monitoring are portable devices that a patient wears home and then returns to us for analysis.
More Information about Stress Tests:
A nuclear cardiac stress test, or Myocardial Perfusion Imaging (M.P.I.), is a test designed to help a physician diagnose heart disease. This is done by taking nuclear images of a patient's heart before and after stressing it, and then comparing the images. Nuclear imaging shows blood perfusion to and from the heart muscle, and it also allows for a calculation of the left ventricle ejection fraction (%LVEF), or how well the left ventricle is actually pumping blood throughout the body.
Before the patient comes in, they are informed to have nothing but water after midnight before the test. It is important the patient has no caffeine for at least 24 hours before the test. This includes even decaf coffees, teas, caffeine-free sodas, chocolate, and medications such as Anacin and Excedrin. Also, if the patient is taking any cardiac medications, especially Beta-blockers, the ordering doctor should discuss with the patient if these should be withheld for the test.
The study can be as short as two hours and as long as four hours. When the patient arrives, a set of "resting" nuclear images is made possible by injecting the patient with a radioactive isotope. There are no side effects from this injection; however it does need to circulate in the patient's body for 30-45 minutes in order to be taken up by the heart muscle to a greater extent than the other organs in the body. The images involve the patient lying on the table while the camera rotates around their chest for about 15 minutes. These moving images are called SPECT imaging and are similar to CT scans in the respect that it produces slices of the heart muscle, as well as a 3-D rotating image. When finished with the "resting" images, the patient then moves to the stress treadmill room for the stress portion of the test. There is a M.A. who preps the patient with a 12 lead EKG, blood pressure, and obtains the pt. cardiac history. Stress tests are always attended by a physician, whether is be the hospitalist on staff or a cardiologist.
If the patient is able to walk, the treadmill is always the best form of cardiac stress. They usually walk until 85% of their maximum predicted heart rate is achieved. At that point, the radioactive isotope is injected once more to allow for a set is "stress" images to be acquired after the stress test. If a patient is unable to walk for any reason, a chemical or pharmacological stress test can be performed. The most common type is either Adenosine or Lexiscan. Bridgton Hospital has recently switched over to using Lexiscan on a regular basis however both work in a similar fashion by dilating the blood vessels throughout the body, and therefore "stressing" the heart while the patient sits in a chair. Most common side effects can include flushing, headache, and slight shortness of breath, but they should completely resolve within a few minutes. If a patient has a history of asthma or restrictive airway disease, due to the side effects of Adenosine and Lexiscan, a Dobutamine stress may be ordered instead. This type of pharmacological stress actually increases the heart rate, as if the patient was exercising, but the effects can linger much longer. For this reason, Dobutamine must be administered by a registered nurse and medication may be needed to reverse the effects as well. No matter which way the patient's heart undergoes stressing, they are all given something to eat and drink immediately after while the radioactive isotope is circulating the 30-45 minutes needed. The "stress" images are essentially the same as the "rest" images, but are also gated with a 3 lead EKG to help calculate the %LVEF. At this point the patient is finally finished.