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Chapter 30 Coordinating Care for Patients With Cardiac Disorders
It is measured every 6 hours after admission to the hospi- tal to evaluate evolving ischemia. This is known as serial cardiac biomarker testing. Laboratory tests diagnostic for CAD are summarized in Table 28.3 in Chapter 28. An electrocardiogram (ECG) is often the initial test when CAD is suspected. During anginal episodes or symp- toms of ACS, the ECG may show ST-segment depression of greater than 0.5 mm or flat or inverted T waves that are indicative of ischemia. These changes return to normal when chest pain is relieved. It is important to note that ischemia in some patients may be electrically silent, with an ECG that appears normal. Serial ECGs may be done with cardiac biomarkers to rule out an infarction. If cardiac bio- markers and ECGs are normal, a patient may then undergo an exercise stress test . This is done to assess the function of the heart during exercise. Alternatively, for those who are unable to use a treadmill or stationary bicycle, pharmacolog- ical agents such as dobutamine can be used to increase heart rate, mimicking the effects of exercise on the heart. Stress echocardiograms are another option. Stress testing can be combined with nuclear imaging, such as thallium or tech- netium studies, to further evaluate perfusion to the heart. The goals of the stress test are (a) to determine whether there is reduced oxygen-rich blood flow to the heart tissue during physical activity and (b) to determine what parts of the heart are affected by the decreased blood flow. Descrip- tions of these tests can be found in Chapter 28. A common test for diagnosing CAD is coronary angiog- raphy, a left-sided cardiac catheterization with the purpose of evaluating the coronary arteries for blockage. This is per- formed to determine the location of the plaque within the coronary circulation, the degree of occlusion, and whether the area can be treated with percutaneous transluminal coronary angioplasty. The lack of major plaque limits the diagnostic value of this test in patients with nonobstruc- tive CAD. Coronary computed tomography angiography (CCTA), cardiographic magnetic resonance (CMR), stress echocardiograms, and stress imaging techniques can also be useful tests. Diagnostic tests will be based on a patient’s signs and symptoms, cardiac and health history, and risk factors. ACS Evaluation After Unexpected Fall Thirty-three percent of all patients with acute coronary syndrome are over 75. Because older patients tend to have multiple health problems or diseases that are also associated with chest pain, identification of cardiac problems can be delayed, which increases risk of com- plications. Healthcare team members should be aware that symptoms such as shortness of breath, syncope, acute delirium, or an unexplained fall can be caused by ACS when accompanied by chest pain. Geriatric/Gerontological Considerations
MI and should be treated as an emergency. It is identified as the initial phase of acute coronary syndrome (ACS) . ACS is an umbrella term used to define stages of myo- cardial ischemia. It includes unstable angina, non-ST elevation MI (NSTEMI), and ST elevation MI. ACS is discussed in more detail in Chapter 32. A variation of unstable angina is vasospastic angina, also called Prinzmetal’s or variant angina . The blockage of blood flow in this disorder is caused by coronary artery spasm rather than plaque formation, but atherosclerotic changes are commonly present. It typically occurs at rest and in clusters. Interestingly, it normally occurs at night between midnight and 8 a.m. Angina may radiate to the left arm, back, neck, and jaw. Additional symptoms may accompany angina such as chest pressure, shortness of breath or dyspnea, fatigue, nausea, vomiting, diaphoresis, weakness, syncope, and epigastric discomfort. Males are more likely to present with classic exertional chest pain, whereas women are more likely to complain of atypical chest pain not associated with exer- tion. Females are also more likely to report fatigue, weak- ness, nausea, and dyspnea. Patients with diabetes also do not consistently present with chest pain, often having no signs and symptoms of CAD. It is important to note that not all chest pain is caused by cardiac ischemia. Nonischemic causes can be aortic dissection, pericarditis, gallbladder disease, pleuritic pain, pulmonary embolism, pneumonia, gastroesophageal reflux disease, and other conditions. The formation of plaque within the blood vessels is a silent process. Often CAD is suspected only when the individual presents with clinical symptoms. The diagnosis is made on the basis of clinical presentation and diagnostic findings. Timely recognition of ischemia related to CAD is essen- tial for prompt treatment and improved patient outcomes, particularly in cases where CAD has progressed to acute coronary syndrome or myocardial infarction. Delays in diagnosis can result in more myocardial damage from isch- emia. When time is muscle, every minute counts. Diagnostic Tests Many of the blood tests performed assess for the presence of risk factors for CAD development, such as lipid pro- files, inflammation, and coagulation studies. Lipid profiles evaluate total cholesterol and triglyceride levels as well as LDL and high-density lipoprotein (HDL). Specific car- diac biomarkers are used to rule out MI. Troponin (a pro- tein released into the bloodstream when there is cardiac muscle damage) levels rise when myocardial injury occurs. It is the most accurate and commonly used biomarker to identify when ischemia has led to tissue damage. This biomarker begins to rise two-three hours after damage occurs and continues to rise over the next 12-48 hours. Interprofessional Management Medical Management Diagnosis
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