33 - CVS pathology mcqs - 26 to 30

Question 26
A 51-year-old woman has had several syncopal episodes over the past year. Each episode is characterized by sudden but brief loss of consciousness. She has no chest pain. On physical examination her vital signs show T 36.9 C, P 80/minute, RR 20/minute, and BP 110/75 mm Hg. She has no pedal edema. On brain MR imaging there is a 1.5 cm cystic area in the left parietal cortex. A chest radiograph shows no cardiac enlargement, and her lung fields are normal. Her serum total cholesterol is 165 mg/dL. Which of the following cardiac lesions is she most likely to have?
A Cardiac amyloidosis
B Left atrial myxoma
C Tuberculous pericarditis
D Mitral valve prolapse
E Ischemic cardiomyopathy
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(B) CORRECT. Atrial myxomas are more often on the left. Though benign, they can occlude the mitral valve and produce sudden loss of cardiac output. They may embolize small portions of themselves or thrombus forned over their surface.
(A) Incorrect. Amyloidosis can lead to a restrictive (infiltrative) cardiomyopathy with more gradual onset of congestive heart failure (Note: under anesthesia, cardiac amyloidosis can lead to intractable arrhythmias).
(C) Incorrect. A caseous pericarditis can resolve to a constrictive pericarditis, and syncopal episodes are not likely with this condition.
(D) Incorrect. Mitral prolapse can be a sudden event, though most often there is minimal symptomatology.
(E) Incorrect. Her total cholesterol, at least, does not indicate a risk for ischemic heart disease, and her heart is not enlarged.
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Question 27
A 58-year-old man develops deep venous thrombosis during a hospitalization for prostatectomy. He exhibits decreased mental status 10 days postoperatively, with right hemiplegia. A CT scan of the head shows an acute cerebral infarction in the distribution of the left middle cerebral artery. A chest radiograph reveals cardiac enlargement and prominence of the main pulmonary arteries consistent with pulmonary hypertension. Laboratory studies show a serum troponin I of <0.4>
A Coarctation of the aorta
B Tetralogy of Fallot
C Ventricular septal defect
D Pulmonic stenosis
E Dextrocardia
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(C) CORRECT. This is the infamous 'paradoxical embolus' from right to left. This can only happen if there is a defect that allows passage from right-to left. This can happen across a patent foramen ovale. In this case, the pulmonary hypertension suggests that there may have been a shunt persistent for a long time--a so-called Eisenmenger complex. An atrial or a ventricular septal defect can provide the shunt.
(A) Incorrect. Coarctation does not lead to cyanosis.
(B) Incorrect. Tetralogy leads to a right-to-left shunt.
(D) Incorrect. This is usually part of tetralogy of Fallot, which has a right-to-left shunt from birth.
(E) Incorrect. This is just a malposition of the heart, with the appropriate connections in place and no shunts.
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Question 28
A 25-year-old man dies suddenly and unexpectedly while at a Beverly Hills (or Kings Cross, or Soho...) nightclub late one evening. The medical examiner performs an autopsy. There is no evidence for trauma on external examination of the body. There are no gross pathologic findings of internal organs. Postmortem toxicologic findings are significant for high blood levels of cocaine and its metabolite benzoylecgonine. Which of the following is the most likely histopathologic finding involving his heart?
A Contraction band necrosis
B Myocarditis
C Myofiber disarray
D Coronary thrombosis
E Pericardial tamponade
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(A) CORRECT. This finding has been associated with sudden death and cocaine use. It is thought that it may be mediated by high norepinephrine levels.
(B) Incorrect. Though lymphocytes may be present, they are seen less frequently and prominently than contraction band necrosis.
(C) Incorrect. Myofiber disarray is a feature of hypertrophic cardiomyopathy.
(D) Incorrect. Though atherosclerotic changes can occur with cocaine use, thrombosis of coronaries is not frequent, because the vessels involved are usually smaller coronary branches.
(E) Incorrect. Myocardial rupture does not typically occur with cocaine use, because a large myocardial infarction is not usually found.

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Question 29
A 49-year-old man has the sudden onset of substernal chest pain with radiation to his left arm. This persists for the next 6 hours. He goes to the emergency department and on examination is afebrile. Laboratory studies show a serum troponin I of 18 ng/mL and CK-MB of 8%. Angiography reveals a thrombosis of the left anterior descending coronary artery. During the next 24 hours, which of the following is the most likely complication he will experience?
A Constrictive pericarditis
B Cardiac arrhythmia
C Hepatic necrosis
D Thromboembolism
E Myocardial rupture
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(B) CORRECT. A primary reason for putting a patient with an acute myocardial infarction in hospital is to prevent arrhythmias.
(A) Incorrect: A constrictive pericarditis is typically a complication of tuberculosis, not acute myocardial infarction.
(C) Incorrect. Heart failure following an acute myocardial infarction is not uncommon, but most often the left heart is most affected, with left heart failure leading to pulmonary congestion and edema. Over time, left heart failure may lead to right heart failure which, if severe, may lead to profound hepatic congestion with centrilobular necrosis.
(D) Incorrect. Mural thrombi can form and embolize following acute myocardial infarction, but this is more likely to happen days to weeks to months later.
(E) Incorrect. This is a potential complication with a transmural acute myocardial infarction that happens from 3 to 7 days following the initial ischemic event.

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Question 30
A 60-year-old man had chest pain and was hospitalized. On the first day of admission, his CK-MB fraction was 9.8% of a total CK of 423 U/L. A coronary angiogram revealed 75% stenosis of the left anterior descending artery. Four days later he suddenly becomes worse, with marked hypotension. A pericardiocentesis is performed and returns 150 cc of bloody fluid. Despite aggressive resuscitative measures, he expires. Which of the following microscopic findings is most likely to be present in his left ventricular myocardium at the time of his death?
A Extensive transmural collagen deposition
B Lymphocytic interstitial infiltrates
C Perivascular and interstitial amyloid deposition
D Necrosis with neutrophils and macrophages
E Edema and loss of cross striations
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(D) CORRECT. He has had an acute myocardial infarction complicated by rupture. This is a typical complication about 3 to 5 days following the onset. 75% arterial narrowing is the point at which coronary occlusion becomes very serious.
(A) Incorrect. Collagenization occurs with healing weeks to months following an acute myocardial infarction, and rupture at this point is highly unlikely
(B) Incorrect. Lymphocytic infiltrates are typical for a viral myocarditis, not myocardial infarction
(C) Incorrect. Amyloidosis of the heart leads to a restrictive cardiomyopathy, not to infarction, and rupture does not occur
(E) Incorrect. Edema and loss of cross striations would be seen in the first day of an acute myocardial infarction, but rupture at this point is unlikely.
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