A research center studying cardiovascular pathology is conducting trials in which experimental rabbits are fed sweet peas containing substances that alter connective tissue synthesis and maturation.  The animals are monitored for several weeks prior to euthanasia.  Autopsy shows myxomatous degeneration with pooling of proteoglycans in the media layer and an intact intima layer in large arteries.  The pathologic findings seen in the experiment are most similar to which of the following conditions?

A 34-year-old woman is evaluated in the emergency department due to 1-day of chest and left shoulder pain.  The patient describes the pain as constant and worse in certain positions.  A month ago, she was treated for a skin rash and joint pain.  Her medical history is otherwise unremarkable.  She is a lifetime nonsmoker and does not use alcohol or illicit drugs.  Her father has hypertension and had a stroke at age 64.  Temperature is 37.5 C (99.5 F), blood pressure is 122/70 mm Hg, and pulse is 97/min and regular.  A triphasic, scratchy sound is heard over the left sternal border with the patient sitting up.  The lungs are clear on auscultation.  ECG shows sinus rhythm with ST-segment elevation in all leads except avR and V1.  Which of the following is the most likely diagnosis?

A 57-year-old unconscious man is brought to the emergency department by his wife.  Thirty minutes prior, the patient developed severe chest pain and asked to be taken to the hospital.  On the way, he became unresponsive.  According to his wife, the patient had been having intermittent, short-lived episodes of chest pain over the past several days.  The patient’s medical history is significant for hypertension, type 2 diabetes mellitus, and hypercholesterolemia.  He is not adherent with medications or follow-up.  In the emergency department, the patient has no spontaneous respirations or circulation and is pronounced dead.  An autopsy examination is performed, and a cross-section of the mid-right coronary artery is shown in the exhibit.  Which of the following is the most likely immediate cause of death in this patient?

A 62-year-old man is brought to the emergency department by a friend due to severe shortness of breath.  He is agitated and gasping for air and is unable to provide history.  His friend says the patient has a history of chronic alcohol use and attends Alcoholics Anonymous meetings.  He is unaware of any other medical history.  Temperature is 36.7 C (98 F), blood pressure is 110/70 mm Hg, pulse is 104/min, and respirations are 32/min.  Due to worsening respiratory distress, immediate endotracheal intubation is performed and mechanical ventilation is begun.  The patient is admitted to the intensive care unit and, despite appropriate therapy, dies several hours later.  Autopsy examination is performed, and histopathology of the lungs reveals engorged pulmonary capillaries and abundant intraalveolar, acellular, pink material that is more prominent at the bases.  This patient most likely had which of the following conditions?

A 42-year-old man comes to the emergency department due to severe chest pain that started abruptly 2 hours ago.  The pain is midline, constant, and 10/10 in intensity.  He has had no fever, cough, or shortness of breath.  His only medical condition is hypertension.  On examination, the patient is diaphoretic and is in severe distress due to pain.  Temperature is 37 C (98.6 F), pulse is 116/min, and respirations are 24/min.  Systolic blood pressure is 82 mm Hg in the right arm and 60 mm Hg in the left arm.  Jugular veins are distended with an estimated pressure of 13 cm H₂O.  The lungs are clear to auscultation.  The point of maximal impulse is not palpable.  The extremities are cold with no peripheral edema.  The patient develops cardiac arrest and dies soon after arrival.  Autopsy would most likely reveal which of the following findings?

A 56-year-old woman with unknown medical history is brought to the emergency department in an unresponsive state.  Paramedics were called for sudden-onset, left-sided weakness, and when they arrived at the patient’s house she was having a generalized tonic-clonic seizure.  Antiseizure medications were given and the patient was subsequently intubated.  Evaluation shows a comatose woman with left hemiplegia.  Neuroimaging reveals a large infarction in the right middle cerebral artery territory with cerebral edema.  Despite aggressive interventions, the patient dies from brain herniation.  Autopsy reveals multiple small, nondestructive masses attached to the edges of the mitral valve leaflets.  Microscopy shows that these masses are composed of platelet-rich thrombi, but no organisms are present.  Which of the following is most closely associated with this patient’s heart valve findings?

A 21-year-old man comes to the office due to multiple episodes of syncope.  The patient has no chest discomfort or dyspnea.  He has no known medical problems and does not use tobacco, alcohol, or illicit drugs.  The patient is a computer analyst and leads a mostly sedentary lifestyle.  He reports that several family members have died of sudden cardiac death.  Genetic analysis reveals an ion channel defect.  Due to the defect, cardiac cells show decreased outward potassium flow and resultant prolongation of the action potential.  Which of the following is the most likely consequence of this patient’s disease?

A 17-year-old boy collapses while jogging and dies despite resuscitation efforts.  He has no medical history; however, his family history is significant for an uncle who died suddenly at age 20.  The boy is 185.4 cm (6 ft 1 in) tall and weighs 80 kg (176.4 lb).  Autopsy reveals significant left ventricular hypertrophy predominantly affecting the interventricular septum.  There are no valvular abnormalities.  Assuming the boy died of an inherited condition, which of the following proteins was most likely affected by the relevant mutation?

A 63-year-old man comes to the emergency department with 2 hours of chest pain and shortness of breath.  The pain started as lower sternal discomfort that he attributed to indigestion, but then spread all over the anterior chest.  The patient has never had similar pain before.  Medical history includes hypertension, hyperlipidemia, and diet-controlled type 2 diabetes mellitus.  The patient is an ex-smoker with a 20-pack-year history.  On cardiac auscultation, a systolic murmur is heard.  Basilar crackles are present on both sides.  After initial evaluation, the patient is taken to the cardiac catheterization laboratory and is found to have a coronary artery occlusion, which is successfully revascularized.  The next morning, the patient appears comfortable and wants to go home.  The lungs are clear on auscultation, and no heart murmur is present.  The murmur heard during initial presentation is most likely explained by a pathologic process involving which of the following structures?

A 52-year-old man comes to the office due to periodic substernal chest heaviness.  The pain is precipitated by fast walking, especially uphill and against the wind, and remits after 5 minutes of rest.  The patient has a history of hypertension and smokes a pack of cigarettes a day.  Blood pressure is 140/80 mm Hg and pulse is 80/min.  The lungs are clear to auscultation, and no heart murmurs are heard.  There is no peripheral edema.  Which of the following pathologic states is most likely to be present in this patient?

A 68-year-old man is brought to the emergency department with chest pain.  For the last year, the patient has had exertional chest pain that has progressively worsened.  He was shoveling snow this morning when the pain became unbearable.  He has smoked a pack of cigarettes daily for 40 years.  Blood pressure is 140/100 mm Hg and pulse is 90/min.  Examination showed mild diaphoresis.  The lungs are clear to auscultation.  ECG shows ST-and T-wave changes suggestive of ischemia.  Cardiac enzymes are elevated.  Emergent coronary angiography is performed, which demonstrates significant atherosclerotic involvement of the left anterior descending and circumflex arteries.  Development of these vascular lesions most likely involved growth factors released from which of the following sources?

A 35-year-old previously healthy man is brought to the emergency department after being involved in a motor vehicle collision.  He was an unrestrained driver and hit his chest against the steering wheel during the collision.  When the paramedics reached him, he reported chest discomfort but was hemodynamically stable.  Shortly after arrival at the emergency department, the patient experiences worsening respiratory distress and becomes hypotensive.  On physical examination, the patient appears anxious and is tachycardic and tachypneic.  The trachea is midline; the jugular veins are distended.  The anterior chest wall is bruised and tender to palpation.  Vesicular breath sounds are present bilaterally.  The abdomen is soft and nontender.  Which of the following is the most likely cause of this patient’s clinical deterioration?

Autopsy of a 78-year-old man demonstrates decreased left ventricular cavity size and a sigmoid-shaped ventricular septum.  Light microscopy shows increased collagen content within the ventricular wall.  Some myocardial cells also have brownish perinuclear cytoplasmic inclusions.  The changes described are most consistent with which of the following conditions?

A 61-year-old woman is hospitalized due to chest pressure and shortness of breath.  Two days ago her husband died in a car accident.  The patient’s medical history is significant for hypertension, hyperlipidemia, and gout.  Five years ago, she was diagnosed with breast cancer and treated with surgery and chemotherapy.  Blood pressure is 165/90 mm Hg and pulse is 95/min and regular.  Physical examination is unremarkable.  ECG shows normal sinus rhythm with T-wave inversions in the anterior leads.  Echocardiogram shows hypokinesis of the apical wall with decreased left ventricular ejection fraction.  Diagnostic coronary angiography shows no evidence of obstructive coronary artery disease.  The patient is treated medically and discharged home.  Four weeks later, she is seen in the office and has no symptoms.  Repeat echocardiography demonstrates normal left ventricular wall motion and ejection fraction.  Which of the following is the likely cause of this patient’s initial presentation?

A 32-year-old man dies suddenly in his sleep.  He had been experiencing easy fatigability for the past 6 months and mentioned that he was feeling tired “‘all the time”‘ and needed to take naps during the day.  He did not drink alcohol or use illicit drugs.  He smoked a pack of cigarettes per day for 10 years.  His father died from a “heart problem” at age 40.  On autopsy, the heart appears grossly enlarged.  A layered mural thrombus is seen in the left ventricular apex.  Coronary atherosclerosis is present, with 20% narrowing of the mid-left anterior descending artery and 25% narrowing of the left circumflex artery.  Which of the following is the most likely cause of death of this patient?

A 45-year-old woman collapses and dies despite appropriate resuscitation efforts.  Prior to the episode, she reported substernal chest pressure brought on by exertion, as well as episodes of palpitations and light-headedness.  An autopsy is performed, and myocardial histology is shown in the image below:

Which of the following is the most likely cause of this woman’s condition?

A 27-year-old man comes to the emergency department due to acute-onset chest pain and shortness of breath.  The pain started suddenly an hour ago while he was lifting a box of books.  The patient has no chronic medical conditions, and he was in his usual state of health prior to the onset of symptoms.  He does not use tobacco, alcohol, or illicit drugs.  Height is 182 cm (71.7 in) and weight is 72 kg (158.7 lb).  On physical examination, the patient is in acute respiratory distress.  Temperature is 37 C (98.6 F), blood pressure is 90/60 mm Hg, pulse is 120/min and regular, and respirations are 26/min.  Pulse oximetry shows 86% saturation on room air.  Cardiopulmonary examination reveals pectus excavatum, bilateral pulmonary crackles, and a decrescendo diastolic murmur at the right upper sternal border.  The abdomen is soft and nontender.  There is no peripheral edema.  Subsequently, the patient develops cardiac arrest and dies.  Which of the following histologic changes is most likely to be seen on autopsy?

A 51-year-old man is brought to the emergency department due to chest tightness that started 30 minutes prior to arrival.  His chest discomfort is associated with shortness of breath and nausea.  The patient was shoveling snow off his driveway when his symptoms began.  He has a history of hypertension and type 2 diabetes mellitus.  Initial ECG shows ST elevation in leads I and aVL.  Cardiac enzymes are elevated.  Emergent cardiac catheterization in this patient will most likely show occlusion of which of the following arteries?

A 5-year-old boy is brought to the office by his parents for evaluation of cyanosis with minimal exertion.  The boy has had occasional episodes of “turning blue” that first began during infancy and are now occurring more frequently.  During the episodes, the boy assumes a squatting position as it makes him “feel better.”  The family recently immigrated to the United States; the boy has never had a medical checkup prior to this visit.  Physical examination reveals a prominent right ventricular impulse and a harsh systolic murmur.  Which of the following embryological events is the most likely mechanism that caused this patient’s condition

A 78-year-old woman is hospitalized due to acute myocardial infarction.  The patient had been having intermittent chest pain for 3 days and came to the hospital when the pain became unremitting.  She has type 2 diabetes mellitus, but her medical follow-up has been poor.  On the third day of hospitalization, the patient has sudden-onset shortness of breath due to pulmonary edema.  Echocardiography confirms severe mitral regurgitation.  She is taken immediately to surgery, which reveals rupture of the posteromedial papillary muscle.  This patient’s finding typically suggests compromised blood flow through which of the following coronary arteries?

A 70-year-old man comes to the emergency department due to severe midback pain that started several hours ago.  He describes the pain as excruciating and wants immediate relief.  The patient also has nausea, diaphoresis, and lightheadedness.  He has a history of hypertension and chronic kidney disease.  His medication compliance has been poor.  He is an active smoker with a 40-pack-year history.  His blood pressure on the right arm is 220/105 mm Hg.  ECG shows sinus tachycardia and voltage criteria for left ventricular hypertrophy with secondary ST-segment and T wave changes.  After initial evaluation, a transesophageal echocardiogram shows a dissection flap in the descending aorta but no evidence of dissection in the ascending aorta.  The dissection flap in this patient most likely originates near which of the following points?

A 33-year-old man comes to the emergency department due to fever, chills, cough, and shortness of breath over the last week.  He smokes a pack of cigarettes a day, consumes 2 or 3 alcoholic beverages daily, and uses intravenous heroin 2 or 3 times per week.  He is febrile and tachycardic.  Blood cultures grow Staphylococcus aureus.  Chest x-ray shows bilateral nodular lesions with areas of cavitation.  The valve most likely affected in this patient can be best evaluated by auscultation at which of the following sites?

A 24-year-old primigravid woman at 36 weeks gestation comes to the office due to light-headedness and nausea at bedtime.  Her pregnancy has been uncomplicated, and medical history is unremarkable.  The patient takes folic acid daily but has been unable to tolerate oral iron.  Blood pressure is 115/75 mm Hg when sitting, 110/70 mm Hg when standing, and 80/60 mm Hg when supine.  Physical examination shows a uterus consistent in size with 36 weeks gestation.  Which of the following is the most likely explanation for this patient’s hypotension while supine?

A 10-year-old boy is brought to the clinic by his parents due to chronic fatigue, shortness of breath, and failure to gain weight.  The child was recently adopted from an orphanage in Asia.  He weighs 20 kg (44.2 lb).  Vital signs are within normal limits.  Physical examination reveals a loud systolic murmur.  Echocardiogram shows pulmonary stenosis and subaortic ventricular septal defect with deviation of the origin of the aorta to the right.  The mother describes occasional episodes of severe dyspnea and cyanosis, during which the child quickly assumes a squatting position.  Which of the following mechanisms during squatting relieves this child’s symptoms?

A 75-year-old man is found unresponsive in his home.  Emergency medical services are called by the neighbor, but the patient is pronounced dead at the scene.  The patient had a history of hypertension, type 2 diabetes mellitus, and coronary artery disease, as well as a 25-pack-year smoking history.  He worked at a coal mine in the remote past and retired as an auto mechanic 15 years ago.  Autopsy is performed; a section of lung tissue stained with hematoxylin and eosin is shown below.

Which of the following is the most likely cause of this patient’s abnormal histopathology findings?

A 32-year-old man comes to the office due to progressive dyspnea, dizziness, and chest discomfort.  He has no prior medical problems but had a mild respiratory illness 2 weeks earlier that resolved spontaneously.  His father has a history of myocardial infarction.  Echocardiography shows pericardial fluid accumulation with late diastolic collapse of the right atrium.  Which of the following physical examination findings is most likely to be seen in this patient?

A 36-year-old woman is brought to the emergency department with sudden-onset right side weakness and speech difficulty.  During the last 3 weeks, the patient has experienced progressive fatigue, malaise, and low-grade fevers.  Despite the symptoms, she did not seek medical attention and did not take any medications.  She had a dental extraction 5 weeks ago, which was uncomplicated.  The patient has never previously been significantly ill or hospitalized.  She works as a receptionist at a legal firm and has never traveled outside the United States.  She does not use tobacco, alcohol, or illicit drugs.  The patient is admitted to the hospital, but despite adequate resuscitative measures, she dies 2 hours later.  Gross autopsy shows large, friable irregular masses attached to the atrial surface of a valve.  Which of the following underlying conditions most likely predisposed this patient to developing these cardiac changes?

A 54-year-old man comes to the emergency department with retrosternal chest pain of 30 minutes duration.  The patient also complains of sweating and mild dyspnea.  A single tablet of nitroglycerin is delivered sublingually, and the patient’s pain decreases significantly.  The patient has experienced several similar episodes of pain over the last 12 hours, all of which resolved spontaneously.  Which of the following ultrastructural changes would most likely indicate irreversible myocardial cell injury in this patient?

A 74-year-old man is brought to the emergency department due to acute-onset lower abdominal and back pain that was followed by an episode of syncope 2 hours ago.  The pain is sharp and constant.  He has had no changes in bowel or bladder function.  Other medical conditions include hypertension and hyperlipidemia.  The patient has a 50-pack-year history of smoking cigarettes.  Temperature is 36.9 C (98.4 F), blood pressure is 90/60 mm Hg, pulse is 108/min and regular, and respirations are 18/min.  BMI is 34 kg/m².  The patient is diaphoretic and appears pale.  Heart and lung sounds are normal.  Abdominal examination reveals moderate tenderness to deep palpation in the lower abdomen; there is no guarding or rebound tenderness.  Bowel sounds are normal.  Which of the following is the most likely diagnosis?

A 25-year-old woman comes to the office with a 3-month history of fatigue, myalgias, arthralgias, and a 5-kg (11-lb) weight loss.  She has also recently experienced increased leg pain with physical activity, which resolves with rest.  The patient has no other medical conditions and takes no medications.  Temperature is 37.6 C (99.7 F), and blood pressure is 160/90 mm Hg in the right arm and 120/80 mm Hg in the left.  A bruit is heard over the left subclavian artery.  Left radial pulse and dorsalis pedis pulses in both legs are weak.  The remainder of the examination shows no abnormalities.  Laboratory results reveal a hemoglobin level of 9.8 g/dL and an erythrocyte sedimentation rate of 110 mm/hr.  Which of the following pathologic mechanisms most likely underlies this patient’s current condition?

A 35-year-old woman is brought to the emergency department due to severe right leg pain.  She is a concert pianist with no known medical issues.  During rehearsal, she began experiencing cramping of the right foot that did not improve with stretching or rest.  The pain quickly spread to her calf, and the patient now rates the pain as 9 out of 10 in intensity.  On examination, the right foot and calf appear pale and cool compared with the left, and sensation is diminished.  Right-sided dorsalis pedis and posterior tibial pulses are absent, and the popliteal pulse is barely palpable.  Emergency embolectomy is performed and a gelatinous mass causing arterial occlusion is successfully removed.  Histopathologic section of the mass is shown in the exhibit.  Which of the following is the most likely origin of this patient’s embolus?