CV-Blood Week 3 Flashcards
A 55-year old man is brought to the ER with sudden onset severe substernal chest pain, sweating and dyspnea. The pain does not respond to aspirin or sublingual nitroglycerin. PMH significant for HTN, DM, hyperlipidemia. ECG demonstrated ST-segment elevation in leads I, aVL and V1-V3.
Which region of the heart is most likely affected in this patient, based on the ECG leads?
A. Anteroapical left ventricle
B. Anteroseptal left ventricle
C. Anterolateral left ventricle
D. Inferior wall of left ventricle
Which region of the heart is most likely affected in this patient, based on the ECG leads?
A. Anteroapical left ventricle
B. Anteroseptal left ventricle
C. Anterolateral left ventricle
D. Inferior wall of left ventricle
The patient exhibits signs and symptoms consistent with acute transmural myocardial infarction (MI). Typical symptoms include severe chest pain not relieved by rest or nitroglycerin, diaphoresis, dyspnea, nausea, lightheadedness, palpitations. Peaked T waves are the first ECG sign, reflecting localized hyperkalemia, then ST-segment elevation follows within minutes to hours.
The patient has most likely suffered a transmural infarct of the anterolateral left ventricle (C is correct), as evidenced by ECG changes in the anterior (V1-V3) and lateral (I, aVL) chest leads.
A 55-year old man is brought to the ER with sudden onset severe substernal chest pain, sweating and dyspnea. The pain does not respond to aspirin or sublingual nitroglycerin. PMH significant for HTN, DM, hyperlipidemia. ECG demonstrated ST-segment elevation in leads I, aVL
and V1-V3.
Cardiac catheterization in this patient will most likely show which of the following?
A. Atherosclerotic plaque obstructing 50% of the lumen, no thrombus
B. Atherosclerotic plaque obstructing 80% of the lumen, no thrombus
C. Significant coronary artery vasospasm causing flow obstruction
D. Ruptured atherosclerotic plaque with fully obstructive thrombus
Cardiac catheterization in this patient will most likely show which of the following?
A. Atherosclerotic plaque obstructing 50% of the lumen, no thrombus
B. Atherosclerotic plaque obstructing 80% of the lumen, no thrombus
C. Significant coronary artery vasospasm causing flow obstruction
D. Ruptured atherosclerotic plaque with fully obstructive thrombus
Explanation:
Transmural infarction is most commonly caused by an acute plaque change (rupture) which produces a superimposed thrombus that completely occludes the involved coronary artery (D is correct).
An atherosclerotic plaque obstructing 50% of lumen with no thrombus would be unlikely to produce symptomatic myocardial ischemia. Symptoms of stable angina do not become proeminent until at least 75% of the cross-sectional area of the coronary artery lumen is occluded (A incorrect).
Lesion described in B is a stable plaque producing a fixed obstruction. Patient would most likely be suffering from stable angina, with chest pain induced by exercise and stabilized by rest or sublingual nitroglycerin.
Finally, coronary artery vasospasm (C) occurs in Prinzmetal’s or variant angina, an uncommon condition of episodic angina that occurs at rest. The spasm may occur at sites of coronary atherosclerosis and can result in transient transmural ischemia with ST elevation on ECG. However, the spasm of Prinzmetal’s responds promptly to vasodilators like nitroglycerin .
A 52-year old male presents to your office complaining of periodic substernal chest pain that is precipitated by fast walking, especially uphill and against the wind. The pain remits following 5 minutes of rest. The patient has a history of HTN and smokes a pack of cigarettes a day. Which of the following is the most likely pathophysiologic mechanism of this patient’s condition?
A. Atherosclerotic plaque obstructing 50% of the lumen, no thrombus
B. Atherosclerotic plaque obstructing 80% of the lumen, no thrombus
C. Significant coronary artery vasospasm causing flow obstruction
D. Ruptured atherosclerotic plaque with fully obstructive thrombus
A 52-year old male presents to your office complaining of periodic substernal chest pain that is precipitated by fast walking, especially uphill and against the wind. The pain remits following 5 minutes of rest. The patient has a history of HTN and smokes a pack of cigarettes a day. Which of the following is the most likely pathophysiologic mechanism of this patient’s condition?
A. Atherosclerotic plaque obstructing 50% of the lumen, no thrombus
B. Atherosclerotic plaque obstructing 80% of the lumen, no thrombus
C. Significant coronary artery vasospasm causing flow obstruction
D. Ruptured atherosclerotic plaque with fully obstructive thrombus
Explanation:
- The patient has symptoms characteristic of typical stable angina pectoris: deep, poorly localized chest or arm discomfort (angina) + angina reproducibly associated with physical exertion or emotional stress + relieved within 5 minutes by rest or sublingual nitroglycerin.
- He also has 2 major risk factors for atherosclerosis : HTN and smoking.
- Lesion most often underlying stable angina is a fixed atheromatous obstruction of one or more coronary arteries occluding at least 75% of the luminal cross sectional area. B is correct.
A is no symptoms, C is Prinzmetal’s angina, D is acute MI
A 59-year old woman presents to the ER with crushing chest pain, sweating and lightheadedness. BP is 90/60 and heart rate 48. ECG shows sinus bradycardia and ST segment elevation in leads II, III, aVF. Occlusion of which of the following coronary arteries is most likely responsible for this patient’s condition?
A. Left main coronary artery
B. Left anterior descending artery
C. Left circumflex artery
D. Right coronary artery
A 59-year old woman presents to the ER with crushing chest pain, sweating and lightheadedness. BP is 90/60 and heart rate 48. ECG shows sinus bradycardia and ST segment elevation in leads II, III, aVF. Occlusion of which of the following coronary arteries is most likely responsible for this patient’s condition?
A. Left main coronary artery – gives rise to LAD and LCX, so ST elevations for leads corresponding to both.
B. Left anterior descending artery – V1-V4 mainly
C. Left circumflex artery – V5-V6, I, aVL
D. Right coronary artery – II, III, aVF
Explanation: Patient presents with symptoms and ECG findings consistent with MI of the inferior wall of the heart, which in 90% of individuals is supplied by the posterior descending branch of the right coronary artery (D is correct). Of note, the patient’s bradycardia and hypotension suggests that there may have been ischemic injury to the SA node as well.
A 68-year old man comes to the ER due to lightheadedness, weakness and palpitations. BP is 110/60, pulse 144/min and irregular. ECG shows an irregularly irregular rhythm and absent P waves. Long-term anticoagulation is initiated to prevent atrial thrombus formation and he is eventually discharged home on warfarin. Which of the following is the best test to monitor the anticoagulation effect of warfarin in this patient?
A. Activated partial thromboplastin time
B. Bleeding time
C. Fibrin split products
D. Fibrinogen levels
E. Prothrombin time
A 68-year old man comes to the ER due to lightheadedness, weakness and palpitations. BP is 110/60, pulse 144/min and irregular. ECG shows an irregularly irregular rhythm and absent P waves. Long-term anticoagulation is initiated to prevent atrial thrombus formation and he is eventually discharged home on warfarin. Which of the following is the best test to monitor the anticoagulation effect of warfarin in this patient?
A. Activated partial thromboplastin time
B. Bleeding time
C. Fibrin split products
D. Fibrinogen levels
E. Prothrombin time
Explanation: The patient’s ECG suggests A Fib, which makes thrombus formation more common (especially LA appendage). If this thrombus detaches from the atrial wall, there is a risk of stroke. The oral anticoagulant warfarin reduces thrombus formation risk by inhibiting the activation of Vit K dependent clotting factors II, VII, IX and X. This leads to decreased levels of these factors, particularly Factor VII, therefore prolonging the prothrombin time (E is correct).
- aPTT is used to monitor heparin therapy, which primarily affects the intrinsic coagulation pathway. (A is incorrect).
- Bleeding time is used to assess platelet function. Increased bleeding time can be seen with thrombocytopenia, von Willebrand disease, aspirin therapy etc. (B is incorrect)
- The combination of decreased fibrinogen levels and fibrin split products (D-Dimer) is characteristic of disseminated intravascular coagulation (DIC). (C, D are incorrect).
A 56-year old man comes to the clinic for a routine checkup. PMH includes HTN, Type 2 DM, hyperlipidemia. His blood pressure is 152/101 and pulse 87/min. Waist circumference is 110 cm (43 inches). Laboratory studies show: LDL 161 mg/dL. Fasting blood glucose 201 mg/dL. Hemoglobin A1c: 7.4%.
Which of the following vascular beds is most likely to carry the highest atherosclerotic burden in this patient?
A. Carotid arteries
B. Coronary arteries
C. Mesenteric arteries
D. Renal arteries
A 56-year old man comes to the clinic for a routine checkup. PMH includes HTN, Type 2 DM, hyperlipidemia. His blood pressure is 152/101 and pulse 87/min. Waist circumference is 110 cm (43 inches). Laboratory studies show: LDL 161 mg/dL. Fasting blood glucose 201 mg/dL. Hemoglobin A1c: 7.4%.
Which of the following vascular beds is most likely to carry the highest atherosclerotic burden in this patient?
A. Carotid arteries
B. Coronary arteries
C. Mesenteric arteries
D. Renal arteries
Explanation:
- Patient has multiple risk factors that contribute to atherosclerosis: HTN, DM, hyperlipidemia. Pathophysiology: focal intima thickening due to accumulation of lipid-laden macrophages and extracellular matrix (fatty streaks). With advancing age, there is transition of fatty streaks to atherosclerotic plaques and more advanced lesions develop a lipid-rich necrotic core and regions of calcification.
- The most susceptible vascular regions involve bends and branch points, which cause turbulence and local flow disruption. Of all the major vascular beds, the lower abdominal aorta and coronary arteries (B is correct) are the most susceptible to atherosclerosis. Atherosclerotic lesions occur in these vessels as early as the second decade of life.
A 12-year old boy experiences excessive bleeding following a tooth extraction. PMH includes episodes of painful joint swellings from minor trauma. Laboratory results are as follows:
- Bleeding time: 5 minutes (normal = 2-9 minutes)
- Prothrombin time: 23 seconds (normal = 11-14 seconds)
- Activated partial thromboplastin time: 25 seconds (normal = 25-40 seconds)
Patient most likely has a deficiency involving which of the following factors?
A. Factor VII
B. Factor VIII
C. Factor XI
D. Von Willebrand factor
A 12-year old boy experiences excessive bleeding following a tooth extraction. PMH includes episodes of painful joint swellings from minor trauma. Laboratory results are as follows:
- Bleeding time: 5 minutes (normal = 2-9 minutes)
- Prothrombin time: 23 seconds (normal = 11-14 seconds)
- Activated partial thromboplastin time: 25 seconds (normal = 25-40 seconds)
Patient most likely has a deficiency involving which of the following factors?
A. Factor VII
B. Factor VIII
C. Factor XI
D. Von Willebrand factor
Explanation:
Patient’s hemarthroses and excessive bleeding following tooth extraction are suggestive of a coagulopathy (clotting factor deficiency). Lab results show normal bleeding time, normal aPTT and prolonged PT.
- Normal bleeding time indicates adequate platelet function (vWF is mediator of platelet adhesion to endothelium, therefore deficiency of vWF results in increased bleeding time, D is incorrect). Normal aPTT indicates an intact intrinsic coagulation system (deficiency in either factor VIII and factor XI will result in normal bleeding time, normal PT, prolonged aTT). (B and C are incorrect).
- The prolonged PT indicates a defect in the extrinsic coagulation pathway, most commonly factor VII (A is correct).
