Cardiac cross-sections US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Cardiac cross-sections. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Cardiac cross-sections US Medical PG Question 1: A 58-year-old female presents to her primary care physician with complaints of chest pain and palpitations. A thorough past medical history reveals a diagnosis of rheumatic fever during childhood. Echocardiography is conducted and shows enlargement of the left atrium and narrowing of the mitral valve opening. Which of the following should the physician expect to hear on cardiac auscultation?
- A. Continuous, machine-like murmur
- B. Holosystolic murmur that radiates to the axilla
- C. Opening snap following S2 (Correct Answer)
- D. High-pitched, blowing decrescendo murmur in early diastole
- E. Mid-systolic click
Cardiac cross-sections Explanation: ***Opening snap following S2***
- The patient's history of **rheumatic fever** and echocardiographic findings of **left atrial enlargement** and **mitral valve narrowing** (mitral stenosis) are classic for this condition.
- An **opening snap** is a high-pitched, sharp sound that occurs shortly after **S2** (the second heart sound) and is pathognomonic for **mitral stenosis**, caused by the sudden tensing of the stenotic mitral valve leaflets as they open during diastole.
- The **S2-OS interval** indicates severity: a shorter interval suggests more severe stenosis.
*Continuous, machine-like murmur*
- This type of murmur is characteristic of a **patent ductus arteriosus (PDA)**, which is a congenital heart defect.
- The patient's symptoms and echocardiographic findings are not consistent with PDA.
*Holosystolic murmur that radiates to the axilla*
- This murmur describes **mitral regurgitation**, which is a leaky mitral valve. While rheumatic fever can cause mitral regurgitation, the echocardiogram shows **narrowing** of the mitral valve, not leakage.
- The radiation to the axilla is classical for the regurgitant jet flowing into the left atrium during systole.
*High-pitched, blowing decrescendo murmur in early diastole*
- This murmur is typical for **aortic regurgitation**, indicating a leaky aortic valve.
- The patient's presentation and echocardiogram findings specifically point to **mitral valve involvement** rather than aortic valve issues.
*Mid-systolic click*
- A **mid-systolic click** is characteristic of **mitral valve prolapse**, often followed by a late systolic murmur.
- The echocardiogram findings of **mitral valve narrowing** are not consistent with mitral valve prolapse.
Cardiac cross-sections US Medical PG Question 2: A previously healthy 19-year-old man is brought to the emergency department by his girlfriend after briefly losing consciousness. He passed out while moving furniture into her apartment. She said that he was unresponsive for a minute but regained consciousness and was not confused. The patient did not have any chest pain, palpitations, or difficulty breathing before or after the episode. He has had episodes of dizziness when exercising at the gym. His blood pressure is 125/75 mm Hg while supine and 120/70 mm Hg while standing. Pulse is 70/min while supine and 75/min while standing. On examination, there is a grade 3/6 systolic murmur at the left lower sternal border and a systolic murmur at the apex, both of which disappear with passive leg elevation. Which of the following is the most likely cause?
- A. Prolonged QT interval
- B. Hypertrophic cardiomyopathy (Correct Answer)
- C. Mitral valve stenosis
- D. Mitral valve prolapse
- E. Bicuspid aortic valve
Cardiac cross-sections Explanation: ***Hypertrophic cardiomyopathy***
- This patient's **syncope associated with exertion** (moving furniture) and episodes of **dizziness during exercise** are highly suggestive of hypertrophic cardiomyopathy (HCM).
- The presence of a **systolic murmur at the left sternal border and apex** that **decreases/disappears with passive leg elevation** indicates a dynamic left ventricular outflow tract (LVOT) obstruction that is sensitive to preload changes, a hallmark of HCM.
- Passive leg elevation **increases preload** → **increases LV volume** → **decreases LVOT obstruction** → **decreases murmur intensity**.
*Prolonged QT interval*
- While it can cause syncope, especially exertional, a prolonged QT interval generally **does not present with dynamic murmurs** that change with preload.
- ECG findings (not mentioned here) would be the primary diagnostic clue, not physical exam findings related to murmurs.
*Mitral valve stenosis*
- Mitral stenosis would typically present with a **diastolic murmur** (not systolic) and symptoms like dyspnea, fatigue, and possibly hemoptysis due to elevated left atrial pressure.
- The murmur of mitral stenosis would not characteristically change with passive leg elevation in the manner described.
*Mitral valve prolapse*
- Mitral valve prolapse often presents with a **mid-systolic click** followed by a systolic murmur, which typically **intensifies with standing** or maneuvers that decrease left ventricular volume.
- The murmur described here decreases with leg elevation (increased preload), which is the opposite behavior of a mitral prolapse murmur.
*Bicuspid aortic valve*
- A bicuspid aortic valve can cause an **aortic stenosis murmur** (a systolic ejection murmur heard best at the right upper sternal border) or regurgitation, but it generally **does not cause a dynamic murmur that changes with preload** in this characteristic fashion.
- Symptoms related to bicuspid aortic valve disease (like syncope) would more commonly be associated with significant stenosis, not with a murmur that is acutely sensitive to preload changes.
Cardiac cross-sections US Medical PG Question 3: A 67-year-old man with type 2 diabetes mellitus comes to the emergency department because of lightheadedness over the past 2 hours. He reports that he has had similar episodes of lightheadedness and palpitations over the past 3 days. His only medication is metformin. His pulse is 110/min and irregularly irregular. An ECG shows a variable R-R interval and absence of P waves. The patient undergoes transesophageal echocardiography. During the procedure, the tip of the ultrasound probe is angled posteriorly within the esophagus. This view is most helpful for evaluating which of the following conditions?
- A. Myxoma in the left atrium
- B. Thrombus in the left pulmonary artery
- C. Thrombus in the left ventricular apex
- D. Tumor in the right main bronchus
- E. Aneurysm of the descending aorta (Correct Answer)
Cardiac cross-sections Explanation: ***Aneurysm of the descending aorta***
- When the TEE probe is angled **posteriorly within the esophagus**, it optimally visualizes structures directly posterior to the esophagus, particularly the **descending thoracic aorta**.
- The descending aorta runs parallel and immediately posterior to the esophagus, making this the ideal view for evaluating **aortic aneurysms, dissections, and atherosclerotic disease** of the descending aorta.
- Note: This patient's symptoms (lightheadedness, palpitations) are due to **atrial fibrillation** (irregularly irregular rhythm, absent P waves). The TEE is likely being performed for stroke risk evaluation, but this question tests knowledge of TEE probe positioning and anatomical visualization.
*Myxoma in the left atrium*
- The left atrium is best visualized using **mid-esophageal views** (especially the 4-chamber view at 0-20 degrees), not a posteriorly angled view.
- While TEE is excellent for detecting left atrial myxomas and is commonly performed in AFib patients to evaluate for left atrial appendage thrombus, the posterior angle is not optimal for this structure.
*Thrombus in the left pulmonary artery*
- The pulmonary arteries are located **anterior** to the esophagus, making them poorly visualized with a posteriorly angled probe.
- Pulmonary artery evaluation requires **anterior or superior angulation** of the TEE probe, or CT pulmonary angiography is preferred for pulmonary embolism diagnosis.
*Thrombus in the left ventricular apex*
- The left ventricular apex is best visualized using **transgastric views** (probe in stomach looking upward), not posterior esophageal views.
- LV apex thrombus evaluation requires short-axis and 2-chamber transgastric views at 0-90 degrees.
*Tumor in the right main bronchus*
- The bronchi are **anterior** to the esophagus and are not adequately visualized with TEE, regardless of probe angle.
- TEE is designed for cardiac and great vessel evaluation, not airway pathology; bronchoscopy or CT chest would be appropriate for bronchial tumors.
Cardiac cross-sections US Medical PG Question 4: A 70-year-old woman presents with substernal chest pain. She says that the symptoms began 2 hours ago and have not improved. She describes the pain as severe, episodic, and worse with exertion. She reports that she has had multiple similar episodes that have worsened and increased in frequency over the previous 4 months. Past medical history is significant for diabetes and hypertension, both managed medically. The vital signs include temperature 37.0°C (98.6°F), blood pressure 150/100 mm Hg, pulse 80/min, and respiratory rate 15/min. Her serum total cholesterol is 280 mg/dL and high-density lipoprotein (HDL) is 30 mg/dL. The electrocardiogram (ECG) shows ST-segment depression on multiple chest leads. Coronary angiography reveals 75% narrowing of her left main coronary artery. In which of the following anatomical locations is a mural thrombus most likely to form in this patient?
- A. Left ventricle (Correct Answer)
- B. Left atrium
- C. Aorta
- D. Right atrium
- E. Right ventricle
Cardiac cross-sections Explanation: ***Left ventricle***
- The patient presents with symptoms and ECG findings consistent with **unstable angina** or **non-ST elevation myocardial infarction (NSTEMI)**, indicating myocardial ischemia.
- With **75% left main coronary artery stenosis**, there is high risk of progression to **transmural myocardial infarction (STEMI)**, particularly affecting the anterior wall and septum.
- Mural thrombi in the left ventricle typically form **3-7 days post-infarction** in areas of **dyskinetic or akinetic myocardium** due to blood stasis, endocardial injury, and hypercoagulability (Virchow's triad).
- Left main disease affecting such a large territory makes the **left ventricle the most likely site** for mural thrombus formation.
*Left atrium*
- Mural thrombi in the left atrium are most commonly associated with **atrial fibrillation** due to blood stasis in the **left atrial appendage**.
- This patient's symptoms are characteristic of coronary artery disease affecting the left ventricle, not an atrial arrhythmia.
*Aorta*
- While thrombi can form in the aorta (e.g., in the setting of **atherosclerosis** or **aneurysms**), they are typically mural thrombi associated with specific vascular pathologies.
- The symptoms of **chest pain, ST depression**, and **coronary artery narrowing** point toward a myocardial event, making the left ventricle the most likely site for mural thrombus in this clinical context.
*Right atrium*
- Thrombi in the right atrium are usually associated with conditions leading to **venous stasis, such as deep vein thrombosis**, **central venous catheters**, or **right-sided heart failure**.
- The patient's presentation with exertional chest pain and left main coronary artery narrowing is unrelated to right atrial thrombosis.
*Right ventricle*
- The right ventricle is **much less commonly** affected by ischemic events leading to mural thrombi compared to the left ventricle, due to its **lower oxygen demand** and **different blood supply** (right coronary artery).
- While right ventricular infarction can occur (usually with inferior MI), the **left main coronary artery** supplies the left ventricle, making it the primary concern for mural thrombus formation in this patient.
Cardiac cross-sections US Medical PG Question 5: A 23-year-old man is brought to the emergency department by a coworker for an injury sustained at work. He works in construction and accidentally shot himself in the chest with a nail gun. Physical examination shows a bleeding wound in the left hemithorax at the level of the 4th intercostal space at the midclavicular line. Which of the following structures is most likely injured in this patient?
- A. Right atrium of the heart
- B. Inferior vena cava
- C. Left upper lobe of the lung (Correct Answer)
- D. Left atrium of the heart
- E. Superior vena cava
Cardiac cross-sections Explanation: ***Left upper lobe of the lung***
- The **left upper lobe of the lung** extends to the 4th intercostal space at the midclavicular line, making it the most probable structure to be traversed by a penetrating injury at this location.
- The **pleural cavity** and lung tissue are superficially located in this region, making them highly susceptible to injury from a nail gun.
*Right atrium of the heart*
- The **right atrium** is located predominantly on the right side of the sternum, more centrally, and slightly to the right of the midclavicular line.
- An injury at the **left 4th intercostal space at the midclavicular line** would typically be too lateral and superior to directly injure the right atrium.
*Inferior vena cava*
- The **inferior vena cava (IVC)** enters the right atrium from below, primarily located within the abdomen and passing through the diaphragm at the level of T8.
- Its position is far too **inferior and posterior** relative to the 4th intercostal space to be directly injured by this wound.
*Left atrium of the heart*
- The **left atrium** is the most posterior chamber of the heart and is largely covered by the left ventricle.
- Although part of the heart is on the left, an injury at the **4th intercostal space, midclavicular line**, would likely impact the left ventricle or lung tissue before reaching the left atrium, which is located more posteriorly and medially.
*Superior vena cava*
- The **superior vena cava (SVC)** is located to the right of the midline, formed by the brachiocephalic veins behind the right first costal cartilage.
- Its position is too **medial and superior**, on the right side, to be directly injured by a nail penetrating the left 4th intercostal space at the midclavicular line.
Cardiac cross-sections US Medical PG Question 6: A 55-year-old man visits the clinic with his wife. He has had difficulty swallowing solid foods for the past 2 months. His wife adds that his voice is getting hoarse but they thought it was due to his recent flu. His medical history is significant for type 2 diabetes mellitus for which he is on metformin. He suffered from many childhood diseases due to lack of medical care and poverty. His blood pressure is 125/87 mm Hg, pulse 95/min, respiratory rate 14/min, and temperature 37.1°C (98.7°F). On examination, an opening snap is heard over the cardiac apex. An echocardiogram shows an enlarged cardiac chamber pressing into his esophagus. Changes in which of the following structures is most likely responsible for this patient’s symptoms?
- A. Patent ductus arteriosus
- B. Right ventricle
- C. Left ventricle
- D. Left atrium (Correct Answer)
- E. Right atrium
Cardiac cross-sections Explanation: ***Left atrium***
- The patient's symptoms of **dysphagia (difficulty swallowing)** and **hoarseness** suggest compression of anatomical structures by an enlarged cardiac chamber, which the echocardiogram confirms.
- An enlarged **left atrium**, typically due to **mitral stenosis**, can compress the esophagus (leading to dysphagia) and the **recurrent laryngeal nerve** (leading to hoarseness, known as Ortner's syndrome). The **opening snap** at the apex is also highly characteristic of mitral stenosis.
*Patent ductus arteriosus*
- A **patent ductus arteriosus (PDA)** is a congenital heart defect that typically causes a **continuous murmur** and may lead to pulmonary hypertension or heart failure, but not direct compression of the esophagus or recurrent laryngeal nerve.
- The symptoms of PDA are usually present earlier in life, though uncorrected large PDAs can cause symptoms in adulthood, they do not cause dysphagia or hoarseness through direct esophageal compression.
*Right ventricle*
- An enlarged **right ventricle** usually causes symptoms related to right heart failure like **peripheral edema** or **dyspnea** due to pulmonary hypertension.
- It is not anatomically positioned to compress the esophagus or recurrent laryngeal nerve in a way that would cause dysphagia or hoarseness.
*Left ventricle*
- An enlarged **left ventricle** (e.g., due to hypertension or aortic stenosis) primarily causes symptoms like **dyspnea on exertion** or **angina**.
- While a severely dilated left ventricle can displace other structures, it does not typically cause direct esophageal compression leading to dysphagia or recurrent laryngeal nerve compression leading to hoarseness.
*Right atrium*
- An enlarged **right atrium** might be seen in conditions like tricuspid regurgitation or right heart failure but can manifest as **edema** or **jugular venous distention**.
- It is not anatomically positioned to cause dysphagia or hoarseness from esophageal or recurrent laryngeal nerve compression.
Cardiac cross-sections US Medical PG Question 7: A 71-year-old man undergoes CT angiography for suspected mesenteric ischemia. Axial sections at the L1 level show a dissection flap in the superior mesenteric artery with the true lumen severely narrowed. The false lumen extends into a vessel that crosses anterior to the left renal vein. Coronal reconstructions show this vessel arising from the anterolateral aspect of the aorta at L2. The patient has left flank pain and hematuria in addition to abdominal pain. Synthesize the cross-sectional and vascular anatomy to determine the additional vessel involved.
- A. Left gonadal artery arising from the aorta (Correct Answer)
- B. Left middle colic artery from the SMA
- C. Left renal artery from the aorta
- D. Left inferior phrenic artery
- E. Left lumbar artery
Cardiac cross-sections Explanation: ***Left gonadal artery arising from the aorta***
- The **left gonadal artery** originates from the **anterolateral aspect of the aorta** at the **L2 level** and is known to cross **anterior to the left renal vein** as it descends.
- Compromise or dissection involving this artery can cause **flank pain and hematuria** due to its proximity to the ureter and its vascular territory, correlating with the patient's symptoms.
*Left middle colic artery from the SMA*
- The **middle colic artery** arises from the **SMA** at the level of the lower border of the pancreas and supplies the **transverse colon**.
- While it is a branch of the SMA, its course does not classically cross **anterior to the left renal vein**, nor would its involvement typically cause **hematuria**.
*Left renal artery from the aorta*
- The **left renal artery** arises from the aorta at the **L1-L2 level** but typically passes **posterior to the left renal vein**.
- Although renal artery involvement causes hematuria and flank pain, the specific anatomical description of the vessel crossing **anterior to the renal vein** rules it out.
*Left inferior phrenic artery*
- The **inferior phrenic arteries** usually arise from the aorta just above the **celiac trunk** or from the celiac trunk itself at the **T12-L1 level**.
- These vessels supply the **diaphragm and suprarenal glands** and do not descend to cross the **left renal vein at the L2 level**.
*Left lumbar artery*
- **Lumbar arteries** arise from the **posterior aspect** of the abdominal aorta, usually in four pairs corresponding to the L1-L4 vertebrae.
- They travel **posteriorly** to supply the posterior abdominal wall and spinal cord, making the description of an **anterior crossing** of the renal vein anatomically incorrect.
Cardiac cross-sections US Medical PG Question 8: A 29-year-old pregnant woman at 36 weeks gestation presents with severe right upper quadrant pain and elevated liver enzymes. CT (with abdominal shielding) shows a large subcapsular hematoma of the right hepatic lobe. An axial section at the level of T12 shows the hematoma is located between the liver capsule and parenchyma, with the collection tracking along the bare area of the liver. She develops hypotension. Evaluate the anatomical considerations for determining the optimal surgical approach.
- A. Access requires mobilization of the hepatic flexure of the colon first
- B. The hematoma can be accessed extraperitoneally via the bare area without entering the peritoneal cavity (Correct Answer)
- C. Immediate laparotomy through the ligamentum teres is required for vascular control
- D. The falciform ligament must be divided to access the hematoma
- E. Supracolic omental bursa entry provides the safest approach
Cardiac cross-sections Explanation: ***The hematoma can be accessed extraperitoneally via the bare area without entering the peritoneal cavity***
- The **bare area** of the liver is a region on the posterior-superior surface that lacks a **visceral peritoneum** coating, putting it in direct contact with the diaphragm.
- Because this area is continuous with the **retroperitoneal space**, a hematoma localized here can be managed surgically without violating the peritoneal cavity, which may help limit the spread of hemorrhage.
*Access requires mobilization of the hepatic flexure of the colon first*
- Mobilizing the **hepatic flexure** (Cattell-Braasch maneuver) is used to expose the **inframesocolic** space and the second part of the duodenum.
- The bare area is located superiorly and posteriorly on the liver, making colonic mobilization unnecessary and geographically irrelevant for direct access.
*Immediate laparotomy through the ligamentum teres is required for vascular control*
- The **ligamentum teres** is the obliterated umbilical vein located in the free edge of the **falciform ligament**, extending from the umbilicus to the liver notch.
- Opening the ligamentum teres does not provide vascular control of the hepatic parenchyma or the retroperitoneal bare area regions.
*The falciform ligament must be divided to access the hematoma*
- The **falciform ligament** attaches the liver to the anterior abdominal wall and diaphragm, separating the left and right anatomical lobes.
- Dividing it allows for liver mobilization during **intraperitoneal** surgery, but it is not the anatomical gateway to a posterior, extraperitoneal hematoma tracking along the bare area.
*Supracolic omental bursa entry provides the safest approach*
- The **omental bursa** (lesser sac) is located posterior to the stomach and anterior to the pancreas, providing access to the **posterior surface of the stomach**.
- It does not communicate directly with the **bare area** of the liver, which lies between the layers of the **coronary ligament** at the superior/posterior aspect.
Cardiac cross-sections US Medical PG Question 9: A 58-year-old man with esophageal cancer undergoes staging with CT and endoscopic ultrasound. An axial CT at the level of T6 shows the tumor extending from the esophagus into the space between the descending aorta and the left main bronchus. He develops massive hemoptysis during esophagoscopy. The patient is hemodynamically unstable despite resuscitation. Evaluate the anatomical basis for this complication and predict the most likely vessel injured.
- A. Penetration of the left pulmonary artery
- B. Involvement of intercostal arteries
- C. Direct invasion of the descending thoracic aorta
- D. Erosion into the left inferior pulmonary vein
- E. Fistula formation with a bronchial artery (Correct Answer)
Cardiac cross-sections Explanation: ***Fistula formation with a bronchial artery***
- At the level of **T5-T6**, the esophagus is in close proximity to the **bronchial arteries**, which often arise from the descending thoracic aorta and follow the posterior aspect of the bronchi.
- Erosion by an esophageal tumor into high-pressure systemic **bronchial vessels** is a common cause of **massive hemoptysis** and rapid hemodynamic instability in mid-esophageal malignancies.
*Penetration of the left pulmonary artery*
- The **left pulmonary artery** is located more anteriorly and superiorly relative to the esophagus at the level described.
- While it carries a large volume of blood, it is a **low-pressure system** compared to systemic arteries like the bronchial arteries.
*Involvement of intercostal arteries*
- The **posterior intercostal arteries** run in the intercostal spaces along the ribs, further away from the midline esophageal path.
- Injury to these vessels might cause bleeding, but it would not typically manifest as direct **massive hemoptysis** into the airway during esophagoscopy.
*Direct invasion of the descending thoracic aorta*
- While **aortoesophageal fistulas** lead to catastrophic hematemesis, the clinical presentation of massive **hemoptysis** specifically implies an abnormal communication with the **respiratory tract**.
- The tumor's location described between the aorta and the bronchus makes the smaller **bronchial arteries** the more likely intermediary site of erosion leading to airway bleeding.
*Erosion into the left inferior pulmonary vein*
- The **left inferior pulmonary vein** is situated lower in the mediastinum and is more anterior than the esophageal-aortic interface at T6.
- Injury to a pulmonary vein is less likely to produce the rapid, high-pressure **arterial-grade hemorrhage** seen with bronchial or aortic involvement.
Cardiac cross-sections US Medical PG Question 10: A 42-year-old woman undergoes pelvic MRI for evaluation of a pelvic mass. A mid-sagittal T2-weighted image shows a 6 cm heterogeneous mass arising from the anterior uterine wall, and an axial section at the level of the cervix shows the mass has extended laterally to involve structures within the broad ligament. Analyze the cross-sectional anatomy to predict which structure is at highest risk for injury during surgical resection.
- A. Uterine artery at the level where it crosses the ureter (Correct Answer)
- B. Internal iliac vein
- C. Obturator nerve
- D. Ovarian artery
- E. External iliac artery
Cardiac cross-sections Explanation: ***Uterine artery at the level where it crosses the ureter***
- This structure is located within the **cardinal ligament** (base of the **broad ligament**) at the level of the cervix, placing it directly in the path of a mass extending laterally from the uterus.
- The relationship where the **uterine artery crosses superior to the ureter** ("water under the bridge") is critical, and a mass in this region significantly increases the risk of surgical injury to both structures during ligation.
*Internal iliac vein*
- While the uterine artery originates from the internal iliac system, the **internal iliac vein** is situated posteriorly on the **pelvic sidewall**, well behind the contents of the broad ligament.
- It is generally protected by the **parietal peritoneum** and is not primarily involved in masses confined to the lateral uterine and broad ligament extension.
*Obturator nerve*
- The **obturator nerve** runs along the lateral pelvic wall within the **obturator canal**, far lateral to the midline structures of the uterus and broad ligament.
- Injury usually occurs during **pelvic lymph node dissection** rather than routine resection of a mass involving the medial broad ligament.
*Ovarian artery*
- The **ovarian artery** travels within the **suspensory ligament of the ovary** (infundibulopelvic ligament) and enters the broad ligament superiorly, near the uterine fundus.
- Since the mass is described as extending laterally at the **level of the cervix**, the ovarian vessels are anatomically superior to the primary zone of risk.
*External iliac artery*
- This artery runs along the **medial border of the psoas muscle** and serves as a landmark for the lateral boundary of the true pelvis.
- It is located far lateral to the **cervical and paracervical tissues** where the mass is extending, making it an unlikely site for injury during this specific resection.
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