Hello and Welcome to ‘Ask A Doctor’ service. I have reviewed your query and here is my advice. Lexiscan is a medication used in a cardiac nuclear stress test. It works by increasing blood flow in the coronary arteries. Lexiscan is given intravenously in preparation for a myocardial perfusion imaging (MPI) test. It is used to help produce images of the heart for diagnosing coronary artery disease (CAD). Although extremely rare, there is a possibility that a nuclear stress test could cause a heart attack, dizziness or chest pain. These symptoms can occur during a stress test. Other possible side effects include nausea, shakiness, headache, flushing, shortness of breath and anxiety. Stress echocardiogram seems to be an alternative, which uses ultrasound to see the motion of the heart. However, stress echocardiography is probably a bit less sensitive and more dependent on the expertise of the physician interpreting the test. Test that needs to be selected depends on an individual s situation and the expertise of the available doctors. It would be better to let your doctor know that you are concerned about your father-in-law s age, health and other aspects about the test by discussing their pros and cons, and then choose an appropriate one which you would be comfortable with. Hope the information provided helps. Best wishes.