20181213-20181219 Flashcards
A 48-year-old executive presents to the emergency department because of chest tightness and shortness of breath. ECG shows ST-segment elevations in leads V4, V5, and V6. He has a history of high blood pressure and his father died of heart problems at a young age. Assuming no other cardiac history, which of the following myocardial abnormalities would most likely be seen via light microscopy eight hours after his symptoms began?
A. Contraction bands
B. Granulation tissue
C. Monocytic infiltrate
D. Lymphocytic infiltrate
E. No change can be detected with light microscopy at this time
A 48-year-old executive presents to the emergency department because of chest tightness and shortness of breath. ECG shows ST-segment elevations in leads V4, V5, and V6. He has a history of high blood pressure and his father died of heart problems at a young age. Assuming no other cardiac history, which of the following myocardial abnormalities would most likely be seen via light microscopy eight hours after his symptoms began?
A. Contraction bands
B. Granulation tissue
C. Monocytic infiltrate
D. Lymphocytic infiltrate
E. No change can be detected with light microscopy at this time
Explanation: This man has suffered an MI. He demonstrates two of the five important risk factors for developing heart disease, which include HTN, HL, tobacco use, DM, and a family history of heart disease. The changes that occur in the affected cardiac tissue can be helpful in assessing when the infarct occurred. During the first day after an MI, the affected tissue begins to undergo coagulative necrosis and releases enzymes such as troponin I and CK-MB from the dying cells. Coagulative necrosis is marked in the early stages by preservation of general tissue architecture, with myocytes becoming increasingly eosinophilic. Contraction bands will also be seen, causing myocytes to take on a wavy appearance. Granulation and monocytic infiltrate occurs at about 5-10 days after MI. Lymphocytes are not usually obvious in histological samples after MI.
Learning objective:
130a Explain the pathogenesis of Ischemic Heart Disease (IHD) and relate it to risk factors and treatment.
Which of the following is true regarding the use of protamine sulfate?
A. More effective for reversing LMW heparin compared to unfractionated heparin
B. No effect on action of direct thrombin inhibitors
C. Mechanism is based on highly negative protamine charge
D. Check INR within 4hrs: should drop to <2 to resolve bleed
Which of the following is true regarding the use of protamine sulfate?
A. More effective for reversing LMW heparin compared to unfractionated heparin
B. No effect on action of direct thrombin inhibitors
C. Mechanism is based on highly negative protamine charge
D. Check INR within 4hrs: should drop to <2 to resolve bleed
Explanation: Protamine sulfate binds to heparin due to its positive charge. It has greater effect on undractionated heparin. Reversal of heparin would lead to normalization of PTT (note that heparin inhibits both thrombin and factor Xa).
Learning objective:
Anticoagulation therapy:
Review the various classes of anticoagulants (vitamin K antagonists, heparins, direct factor Xa and thrombin inhibitors) and their loci of action.
Explain how direct factor Xa and thrombin inhibitors differ from warfarin, and why they are replacing warfarin in clinical practice
