ALU 301 Chapter 6 questions and solutions

Factors to evaluate for Cardiac testing - 1. How well the heart is functioning - left ventricular function, commonly measured as ejection fraction (EF). 2. How much heart muscle is damaged or at risk. 3. If there is a risk of sudden death. Sensitivity - A test's ability to perceive and measure amounts or differences, whether small or large. A sensitive medical test is one that will be able to give a positive result when a particular condition is present, even during early stages. Ex - EKG test. Specificity - A test's ability to identify exactly one unique object or situation. A specific medical test is only positive for one particular disease or condition. Ex - EKG test. Bayes' Theorem - "Conditional probability" - a ration method to minimize the diagnostic uncertainty (i.e. false positives and false negatives) surrounding cardiac testing. The results of one cardiac test can be used to improve the accuracy of the tests that follow. Benefits of Bayes' Theorem - It provides a much more rational approach allowing the risk assessment to start with some simple parameters such as age, sex, and the results of routine underwriting, and to use those results to help understand the risk when more powerful cardiac testing has also been performed. Most basic cardiac diagnostic workup - The history and physical taken by a physician. Most valuable element of the physical exam? - Auscultation with the stethoscope. By listening for the timing and intensity of heart sounds, the physician can detect the various murmurs associated with heart disease. Heart murmurs - Diagnosed with a stethoscope and can be systolic, diastolic or continuous. Murmur grades - Grade 1: Barely audible with utmost concentration Grade 2: Soft, but easily heard Grade 3: Loud without thrill Grade 4: Loud with thrill Grade 5: Loud, heard with barely any contact between stethoscope and chest wall Grade 6: Loud, heard with stethoscope off the chest wall Pericardial friction rub - A superficial, high-pitched, or scratchy sound that is diagnostic of pericarditis. Gallop rhythms - Soft, low-pitched sounds that can be normal if found in young, health individuals, but are at times indicative of serious hypertensive disease, cardiac dysfunction, or early heart failure. Troponins - When increased, troponins are the most sensitive and specific biomarkers for myocardial damage and can be elevated when other biomarkers are not. Creatine Phosphokinase (CPK) - Usually elevated at the time of acute MI presentation, but can be normal on first testing. Elevated CPK values usually peak 15-20 hours after the onset of symptoms. CPK-BB - Concentrated in the brain and lungs (CPK-1) CPK-MB - Found mostly in the heart (CPK-2) CPK-MM - Found mostly in skeletal muscle (CPK-3) Aspartate Aminotransferase (AST) - This enzyme is also present in the heart muscle. It is released into the circulation following the injury or death of myocardial cells. The amount of AST in the blood is directly related to the size of the infarct and the amount of time that has passed since the onset of the coronary occlusion. Lactic Acid Dehydrogenase (LDH) - Begins to rise about 12 hours after an infarct and usually returns to normal after CPK and AST have returned to normal. Cardiac Radiography - Commonly known as x-ray. Involves examination of posteroanterior (PA) and lateral chest films to detect pulmonary and cardiac disease. Chest film remains an important tool in emergency room and hospital settings for the evaluation of dyspnea, pneumonia and heart failure. Resting Electrocardiogram (EKG) - A recording or tracing of the electrical impulses within the heart, which regulate the heart's contractions. Characteristic EKG abnormalities are crucial to the diagnosis of arrhythmias, ischemia and infarction, atrial and ventricular enlargement, conduction delays, and pericarditis. EKG limb leads - I, II, III, AVR, AVL, AVF EKG chest leads - V1, V2, V3, V4, V5, V6 EKG abnormalities - 1. Heart rate (tachycardia and bradycardia) 2. Heart rhythm/arrhythmias 3. Axis or position of the heart 4. Cardiac hypertrophy 5. Myocardial infarction and/or ischemia