Chapter 19

  1. Paul’s risk factors include excessive body weight, stress, smoking, atherosclerosis, and a family history of stroke and hypertension.
  2. Paul’s serum lactate level went up because during his period of cardiac and respiratory arrest, most of his organs shifted to anaerobic fermentation to meet their energy needs. Anaerobic fermentation generates lactate as an end product. His lactate dehydrogenase level rose as this enzyme was released by dying myocardial tissue.
  3. Aspirin inhibits blood clotting and therefore helps reduce the likelihood of coronary artery obstruction and MI becoming even worse. Aspirin (325 mg/day) reduces mortality from MI by as much as 50%.
  4. Occlusion of the circumflex coronary artery would produce damage in the left atrium and posterior wall of the left ventricle.
  5. Propanolol is a beta-blocker (see A&P, p. 582). It blocks receptors for epinephrine and norepinephrine, so these catecholamines cannot stimulate cardiac and smooth muscle as strongly. This reduces adrenergic effects on the heart and dilates blood vessels, thus reducing blood pressure and heart rate and giving the heart a rest. Not only does this aid in recovery of the myocardium, but it also reduces the sympathetic effects of the anxiety commonly felt by CCU patients.
  6. Nitroglycerin stimulates dilation of the blood vessels by stimulating nitric oxide (NO) release; NO acts as a local vasodilator. Streptokinase, on the other hand, actually breaks up the clot blocking the coronary artery, thus allowing blood flow to be reestablished.
  7. Intravenous drug users are at increased risk for endocarditis because they may use nonsterile needles and fail to clean injection sites, thus introducing bacteria into the bloodstream.
  8. The right ventricle has less muscle mass than the left and is therefore more easily compressed by fluid in the pericardial cavity
  9. A heart attack causes considerable fear and anxiety. It is very important in cardiac care to reassure the patient, calm his or her anxiety, and provide a peaceful, restful atmosphere. The patient should be sheltered from influences such as excessive visitation, radio, TV, and newspapers that may arouse the emotions or accentuate his or her worry, but should not be made to feel isolated from the outside world. A window, clock, and calendar promote a calming sense of connection with the world outside the hospital.
  10. (c) A childhood history of rheumatic fever would predispose a person toward bicuspid valve insufficiency.