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Cardiac Pericardium FRCR 2A QBANK

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Question 1: Pericardial Constriction

Stem: A 62-year-old man with a remote history of tuberculosis presents with ascites, elevated jugular venous pressure (JVP) with Kussmaul’s sign, and peripheral oedema. A CT chest shows a circumferentially thickened pericardium (6 mm) with dense, ring-like calcification. The ventricles are normal in size.

Question: What is the most likely diagnosis?

(A) Cardiac Tamponade (B) Dilated Cardiomyopathy (C) Restrictive Cardiomyopathy (D) Constrictive Pericarditis (E) Endomyocardial Fibrosis

Correct Answer: (D) Constrictive Pericarditis.

Explanation:

  • Why (D) is correct: This is the classic presentation. The patient has signs of right-sided heart failure (ascites, elevated JVP, oedema). The key imaging findings of a thickened (>4 mm) and calcified pericardium are pathognomonic for chronic constrictive pericarditis. The calcified “shell” prevents the ventricles from expanding in diastole, causing all the symptoms.
  • Why (A) is wrong: Cardiac tamponade is an acute condition caused by a large effusion, which would appear as fluid, not calcification.
  • Why (C) is wrong: Restrictive cardiomyopathy (e.g., amyloid) presents with identical symptoms (diastolic dysfunction) but is a myocardial disease. The pericardium would appear normal, and the ventricles may be thick.
  • Why (B) is wrong: Dilated cardiomyopathy involves a globally dilated, hypocontractile heart, not normal-sized ventricles tethered by a calcified pericardium.
  • Why (E) is wrong: Endomyocardial fibrosis is a cause of restrictive cardiomyopathy and would not feature pericardial calcification.

Key Points: Constrictive Pericarditis

  • Pathology: A rigid, non-compliant pericardium (often scarred or calcified) impairs diastolic filling of the heart.
  • Clinical: Kussmaul’s sign (JVP rises with inspiration), ascites, oedema, pericardial “knock.”
  • Causes: Idiopathic, post-surgical, post-radiation, or infectious (especially TB).
  • CT/MRI Findings:
    • Pericardial thickening (>4 mm).
    • Pericardial calcification (highly specific).
    • Dilated atria and IVC.
    • “Sigmoid” or S-shaped interventricular septum (due to discordant pressures).

Question 2: Ischemic LGE Pattern

Stem: A 58-year-old man with a history of a myocardial infarction 6 months ago undergoes a Cardiac MRI (CMR). The Late Gadolinium Enhancement (LGE) images demonstrate an area of bright signal that is most intense in the subendocardium and extends outwards, covering the full thickness of the apical wall, consistent with the LAD territory.

Question: This pattern of LGE is most specific for what?

(A) Myocarditis (B) Cardiac Sarcoidosis (C) Ischemic Cardiomyopathy (D) Cardiac Amyloidosis (E) Hypertrophic Cardiomyopathy

Correct Answer: (C) Ischemic Cardiomyopathy.

Explanation:

  • Why (C) is correct: The subendocardial layer is the most vulnerable to ischemia. Therefore, infarction always starts at the subendocardium and progresses outwards (the “wavefront phenomenon”). Any LGE pattern that involves the subendocardium and follows a coronary artery territory is, by definition, ischemic.
  • Why (A) is wrong: Myocarditis causes non-ischemic LGE, typically in the epicardial or mid-wall layers.
  • Why (B) is wrong: Sarcoidosis causes patchy, non-ischemic LGE, classically in the mid-wall of the basal septum.
  • Why (D) is wrong: Amyloidosis causes a very specific diffuse, global subendocardial LGE, making the blood pool appear dark (“zebra sign”). It does not respect a coronary territory.
  • Why (E) is wrong: Hypertrophic Cardiomyopathy (HCM) shows patchy, non-ischemic LGE, typically in the mid-wall at the points of maximum hypertrophy.

Key Points: Late Gadolinium Enhancement (LGE) Patterns

  • Ischemic: Subendocardial or transmural; respects a coronary artery territory.
  • Non-Ischemic (General): Does not involve the subendocardium (or only does so globally, like amyloid).
  • Myocarditis: Epicardial or mid-wall, non-vascular.
  • HCM: Patchy mid-wall at insertion points or in thickest segments.
  • Amyloid: Diffuse, global subendocardial or transmural, “zebra sign”.
  • Sarcoid: Patchy mid-wall or epicardial, basal septum is a classic site.

Question 3: Hypertrophic Cardiomyopathy (HCM)

Stem: A 22-year-old athlete collapses during practice. A Cardiac MRI is performed, which reveals a diastolic interventricular septal thickness of 28 mm, compared to a lateral wall thickness of 11 mm. There is patchy mid-wall LGE at the RV insertion points.

Question: What is the most likely diagnosis?

(A) Hypertensive Heart Disease **(B) ** “Athlete’s Heart” (C) Hypertrophic Cardiomyopathy (HCM) (D) Cardiac Amyloidosis (E) Aortic Stenosis

Correct Answer: (C) Hypertrophic Cardiomyopathy (HCM).

Explanation:

  • Why (C) is correct: The key finding is asymmetric septal hypertrophy (ASH). A wall thickness >15 mm that is asymmetric (septum >> lateral wall) is the hallmark of HCM. The presence of LGE is a risk factor for sudden cardiac death, fitting the clinical picture.
  • Why (A) is wrong: Hypertensive heart disease causes concentric (symmetric) hypertrophy, not asymmetric.
  • Why (B) is wrong: “Athlete’s Heart” is a physiological, symmetric hypertrophy, and wall thickness almost never exceeds 15 mm.
  • Why (D) is wrong: Amyloidosis also causes symmetric thickening, but with a characteristic diffuse LGE pattern and signs of diastolic dysfunction.
  • Why (E) is wrong: Chronic aortic stenosis causes concentric left ventricular hypertrophy (LVH) as a response to pressure overload.

Key Points: Hypertrophic Cardiomyopathy (HCM)

  • Pathology: A genetic disorder causing unexplained myocardial hypertrophy.
  • Key Finding: Asymmetric septal hypertrophy (ASH) is most common. Wall thickness > 15 mm.
  • Complications: Sudden cardiac death (SCD), heart failure, atrial fibrillation.
  • MRI Findings:
    • Asymmetric hypertrophy (septum > lateral wall).
    • Systolic Anterior Motion (SAM) of the mitral valve.
    • Patchy, mid-wall LGE (a risk factor for SCD).

Question 4: Cardiac Amyloidosis

Stem: A 72-year-old man presents with heart failure with preserved ejection fraction (HFpEF) and low voltages on his ECG. A Cardiac MRI shows symmetric biventricular hypertrophy. On LGE imaging, the myocardium is impossible to null against the blood pool, and there is diffuse, faint subendocardial enhancement throughout both ventricles.

Question: What is the most likely diagnosis?

(A) Hypertensive Heart Disease (B) Hypertrophic Cardiomyopathy (C) Cardiac Amyloidosis (D) Ischemic Cardiomyopathy (E) Cardiac Sarcoidosis

Correct Answer: (C) Cardiac Amyloidosis.

Explanation:

  • Why (C) is correct: This is the classic CMR description of amyloid. The combination of symmetric hypertrophy and a diffuse, global subendocardial LGE pattern is pathognomonic. The “impossible to null” finding (due to gadolinium rapidly filling the interstitium) and the low-voltage ECG (despite thick walls) are also classic.
  • Why (A) is wrong: Hypertensive heart disease causes symmetric hypertrophy but would not have this LGE pattern.
  • Why (B) is wrong: HCM causes asymmetric hypertrophy.
  • Why (D) is wrong: Ischemic cardiomyopathy would have LGE in a vascular territory.
  • Why (E) is wrong: Sarcoidosis causes patchy, mid-wall or epicardial LGE.

Key Points: Cardiac Amyloidosis

  • Pathology: A restrictive cardiomyopathy caused by infiltration of amyloid protein.
  • Clinical: HFpEF, low-voltage ECG despite thick walls.
  • CMR Findings:
    • Symmetric LVH (may also involve RV and atria).
    • LGE Pattern: Diffuse, global subendocardial or transmural enhancement.
    • Nulling: Difficulty/impossibility in nulling the myocardium (a key sign).
    • Biatrial enlargement and pericardial effusions are common.

Question 5: Left Atrial Myxoma

Stem: A 55-year-old woman presents with symptoms of a transient ischemic attack (TIA). A CT chest performed as part of the workup reveals a 4 cm, heterogeneous, low-attenuation mass within the left atrium. The mass is pedunculated (on a stalk) and is seen to arise from the interatrial septum at the fossa ovalis.

Question: What is the most likely diagnosis?

(A) Left Atrial Thrombus (B) Left Atrial Myxoma (C) Metastasis (e.g., from renal cell carcinoma) (D) Lipoma (E) Papillary Fibroelastoma

Correct Answer: (B) Left Atrial Myxoma.

Explanation:

  • Why (B) is correct: This is the textbook location and description. The vast majority (>75%) of myxomas are in the left atrium, and they classically arise from the interatrial septum at the fossa ovalis. They are the most common primary cardiac tumour and can cause embolic strokes.
  • Why (A) is wrong: A thrombus is a common cause of stroke but is typically located in the left atrial appendage, especially in patients with atrial fibrillation. It would not be pedunculated from the septum.
  • Why (C) is wrong: Metastases are more common than primary tumours but are usually solid, enhancing, and located in the myocardium (from hematogenous spread), not pedunculated in the left atrium.
  • Why (D) is wrong: A lipoma would be fat attenuation (-50 to -100 HU), not just “low-attenuation” (which for a myxoma is 20-40 HU).
  • Why (E) is wrong: A papillary fibroelastoma is the most common tumour of the valves (a small, mobile “frond-like” mass), not the interatrial septum.

Key Points: Atrial Myxoma

  • Pathology: Most common primary benign tumour of the heart.
  • Location: ~75% in the Left Atrium, arising from the interatrial septum.
  • Clinical: Can cause constitutional symptoms (fever, weight loss), obstructive symptoms (mimicking mitral stenosis), or embolic events (stroke).
  • Imaging: A pedunculated, heterogeneous, often low-attenuation (myxoid) mass.

Question 6: Acute Myocarditis

Stem: A 28-year-old man presents with acute chest pain and an elevated troponin two weeks after a significant viral illness. His coronary angiogram is normal. A Cardiac MRI shows myocardial oedema on T2-weighted images and patchy LGE in a non-vascular distribution, confined to the epicardial and mid-wall layers of the lateral LV wall.

Question: What is the most likely diagnosis?

(A) Acute Myocardial Infarction (B) Acute Myocarditis (C) Hypertrophic Cardiomyopathy (D) Takotsubo Cardiomyopathy (E) Pericarditis

Correct Answer: (B) Acute Myocarditis.

Explanation:

  • Why (B) is correct: This is the classic “Lake Louise Criteria” presentation. The clinical picture (young, viral prodrome, troponin rise, normal coronaries) strongly suggests myocarditis. The LGE pattern of epicardial and/or mid-wall enhancement in a non-vascular territory confirms it.
  • Why (A) is wrong: An acute MI (infarction) would have subendocardial LGE in a specific coronary territory.
  • Why (C) is wrong: HCM is a chronic condition of hypertrophy, not an acute illness, and has LGE at RV insertion points.
  • Why (D) is wrong: Takotsubo (“stress”) cardiomyopathy presents acutely but is defined by apical ballooning and a lack of LGE (as it’s just stunned myocardium, not scarred).
  • Why (E) is wrong: Acute pericarditis would show enhancement of the pericardium itself, not the myocardium.

Key Points: Acute Myocarditis

  • Pathology: Inflammation of the myocardium, often post-viral.
  • Clinical: Young patient, chest pain, troponin rise, normal coronary arteries.
  • CMR Findings (Lake Louise Criteria):
    • Myocardial oedema (high T2 signal).
    • LGE Pattern: Epicardial or mid-wall, non-vascular distribution.
    • Often involves the inferolateral wall.

Question 7: ARVC

Stem: A 25-year-old man presents with ventricular tachycardia and an ECG showing Epsilon waves. A Cardiac MRI is performed, which demonstrates a severely dilated and hypocontractile right ventricle with focal aneurysms of the free wall. T1-weighted images show fibro-fatty infiltration of the RV myocardium.

Question: What is the most likely diagnosis?

(A) Dilated Cardiomyopathy (DCM) (B) Uhl’s Anomaly (C) Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) (D) Brugada Syndrome (E) Congenital Absence of the Pericardium

Correct Answer: (C) Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC).

Explanation:

  • Why (C) is correct: This is the classic description. ARVC is a disease of the right ventricle leading to arrhythmias. The key imaging findings are RV dilatation, regional wall motion abnormalities (aneurysms/dyskinesia), and fibro-fatty infiltration of the RV free wall. The clinical picture (young patient, VT, Epsilon waves) is also classic.
  • Why (A) is wrong: DCM is typically a biventricular or left-sided disease.
  • Why (B) is wrong: Uhl’s Anomaly is a congenital “parchment heart” with near-total absence of the RV myocardium; it is extremely rare. ARVC is a progressive replacement of myocardium.
  • Why (D) is wrong: Brugada Syndrome is a purely electrical disorder (a channelopathy) and has a structurally normal heart on imaging.
  • Why (E) is wrong: Congenital absence of the pericardium would cause the heart to be displaced leftward, with the LV apex “peeking” behind the sternum. It does not cause RV fatty infiltration.

Key Points: Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC)

  • Pathology: A genetic disorder where RV myocardium is progressively replaced by fibro-fatty tissue, leading to arrhythmias and sudden death.
  • Clinical: Young patient, palpitations, syncope, ventricular tachycardia.
  • CMR Findings (Task Force Criteria):
    • Major: Regional RV akinesia/dyskinesia/aneurysm + RV dilatation + reduced RV function.
    • Major: Fibro-fatty replacement of the RV myocardium.

Question 8: True Ventricular Aneurysm

Stem: A 68-year-old man, 4 months post-anterior MI, has a chest X-ray showing a prominent bulge on the left heart border. A CT scan confirms a dyskinectic, wide-mouthed out-pouching of the LV apex. The wall of this pouch is thin, fibrotic, and calcified.

Question: What is the most likely diagnosis?

(A) Left Ventricular Pseudoaneurysm (B) Left Ventricular True Aneurysm (C) Hypertrophic Cardiomyopathy (apical variant) (D) Pericardial Cyst (E) Ventricular Septal Defect

Correct Answer: (B) Left Ventricular True Aneurysm.

Explanation:

  • Why (B) is correct: A true aneurysm is a late complication of a transmural MI. It is an area of dead, fibrotic myocardium that bulges outwards. The key differentiating feature is a wide-mouthed connection to the LV cavity, and its wall is composed of thin, non-contractile myocardium.
  • Why (A) is wrong: A pseudoaneurysm is an acute complication (a contained rupture). Its key feature is a narrow neck (the rupture site), and its wall is formed only by pericardium, not myocardium. It has a high risk of rupture.
  • Why (C) is wrong: Apical HCM would show a thickened, hypertrophied apex, not a thin, dyskinetic bulge.
  • Why (D) is wrong: A pericardial cyst is a water-attenuation cyst outside the myocardium.
  • Why (E) is wrong: A VSD is a hole in the septum, not a bulge of the free wall.

Key Points: True vs. Pseudoaneurysm

  • True Aneurysm:
    • Time: Late complication (weeks to months post-MI).
    • Wall: Thinned, scarred myocardium (all 3 layers).
    • Neck: Wide.
    • Risk: Low risk of rupture; risk of thrombus/arrhythmia.
  • Pseudoaneurysm:
    • Time: Acute complication (days to weeks post-MI).
    • Wall: Pericardium only (contained rupture).
    • Neck: Narrow.
    • Risk: High risk of free rupture; a surgical emergency.

Question 9: Cardiac Tamponade

Stem: A 45-year-old woman with metastatic breast cancer presents to the emergency department with severe dyspnoea, hypotension, and muffled heart sounds. An urgent contrast-enhanced CT shows a large, circumferential pericardial effusion. The key hemodynamic finding is diastolic flattening of the right ventricular free wall and compression of the IVC.

Question: This combination of findings is diagnostic of:

(A) Constrictive Pericarditis (B) Acute Pulmonary Embolism (C) Cardiac Tamponade (D) Restrictive Cardiomyopathy (E) Severe Mitral Regurgitation

Correct Answer: (C) Cardiac Tamponade.

Explanation:

  • Why (C) is correct: This is the definition of cardiac tamponade. A pericardial effusion (in this case, likely malignant) is under high pressure, preventing the heart from filling. The key sign is hemodynamic compromise (hypotension) caused by diastolic collapse of the right-sided chambers (RV and RA), which are under lower pressure.
  • Why (A) is wrong: Constriction is caused by a thickened, rigid pericardium, not a large fluid-filled effusion.
  • Why (B) is wrong: A massive PE would cause RV dilatation and bowing of the interventricular septum to the left (pressure overload), not external compression of the RV.
  • Why (D) is wrong: Restrictive cardiomyopathy is an intrinsic muscle disease and would not have a large pericardial effusion.
  • Why (E) is wrong: Severe MR would cause a dilated left atrium, not RV collapse.

Key Points: Cardiac Tamponade

  • Pathology: A pericardial effusion under pressure, leading to impaired diastolic filling and hemodynamic collapse.
  • Clinical: Beck’s Triad (hypotension, muffled heart sounds, elevated JVP). Pulsus paradoxus.
  • Imaging:
    • Large pericardial effusion.
    • Diastolic collapse/flattening of the RV free wall.
    • Compression of the RA.
    • Dilated, non-collapsing IVC (back-pressure).

Question 10: Cardiac Sarcoidosis

Stem: A 48-year-old woman with known pulmonary sarcoidosis presents with new-onset complete heart block requiring a pacemaker. A Cardiac MRI is performed, which reveals patchy, nodular areas of LGE. This enhancement is most prominent in the mid-wall of the basal interventricular septum.

Question: This specific pattern of LGE is most characteristic of:

(A) Cardiac Sarcoidosis (B) Ischemic Heart Disease (C) Hypertrophic Cardiomyopathy (D) Myocarditis (E) Cardiac Amyloidosis

Correct Answer: (A) Cardiac Sarcoidosis.

Explanation:

  • Why (A) is correct: The clinical context (known sarcoid, heart block) is a major clue. The LGE pattern of patchy, mid-wall enhancement with a predilection for the basal septum is the most classic (though not only) finding in cardiac sarcoidosis, as this is where granulomas often form.
  • Why (B) is wrong: Ischemic disease is subendocardial and follows a vascular territory.
  • Why (C) is wrong: HCM involves hypertrophy and LGE at RV insertion points or in the thickest segments, not typically the basal septum alone.
  • Why (D) is wrong: Myocarditis is also mid-wall/epicardial but classically involves the lateral wall and does not have the same strong association with heart block.
  • Why (E) is wrong: Amyloid is a diffuse, global subendocardial process.

Key Points: Cardiac Sarcoidosis

  • Pathology: Non-caseating granulomatous infiltration of the myocardium.
  • Clinical: Can be asymptomatic or present with arrhythmias, heart block, or heart failure.
  • CMR Findings:
    • LGE Pattern: Patchy, non-vascular, mid-wall or epicardial.
    • Classic Location: Basal interventricular septum and basal lateral wall.
    • May also show myocardial thinning/aneurysm in late stages.

Question 11: Calcific Aortic Stenosis

Stem: A 78-year-old man presents with exertional syncope, dyspnoea, and angina. A gated, non-contrast cardiac CT is performed. The images demonstrate bulky, irregular calcification of all three leaflets of the aortic valve, resulting in restricted motion.

Question: What is the most likely diagnosis?

(A) Rheumatic Heart Disease (B) Bicuspid Aortic Valve (C) Degenerative Calcific Aortic Stenosis (D) Aortic Valve Endocarditis (E) Hypertrophic Obstructive Cardiomyopathy (HOCM)

Correct Answer: (C) Degenerative Calcific Aortic Stenosis.

Explanation:

  • Why (C) is correct: This is the most common cause of aortic stenosis in an elderly patient. It is a degenerative “wear and tear” process, resulting in bulky calcification starting at the leaflet bases. The clinical triad (syncope, angina, dyspnoea) is classic.
  • Why (A) is wrong: Rheumatic heart disease also causes AS, but it is characterized by commissural fusion (fusion of the leaflet tips) and is almost always accompanied by mitral valve disease.
  • Why (B) is wrong: A bicuspid valve is a congenital cause and would be seen in a younger patient. It has a characteristic “fish mouth” appearance and only two leaflets.
  • Why (D) is wrong: Endocarditis would present with vegetations (irregular, mobile masses on the leaflets) and clinical signs of infection, not just calcification.
  • Why (E) is wrong: HOCM causes sub-aortic obstruction (from the thick septum), not valvular obstruction.

Key Points: Degenerative Aortic Stenosis

  • Pathology: Most common cause of AS in the elderly.
  • Clinical Triad: Angina, Syncope, Dyspnoea (Heart Failure).
  • Imaging:
    • CT: Bulky, irregular calcification of a tri-leaflet valve, starting at the bases.
    • Echo/CMR: Restricted leaflet motion, high-velocity jet.

Question 12: Left Atrial Appendage Thrombus

Stem: A 71-year-old man with known persistent atrial fibrillation is scheduled for a cardioversion. A pre-procedural cardiac CT is performed with a delayed-phase scan. The images reveal a persistent, low-attenuation filling defect confined to the tip of the left atrial appendage.

Question: What is the most likely diagnosis?

(A) Atrial Myxoma (B) Left Atrial Appendage Thrombus **(C) ** Pectinate Muscles (D) Incomplete Mixing Artifact (E) Metastasis

Correct Answer: (B) Left Atrial Appendage Thrombus.

Explanation:

  • Why (B) is correct: The most common site for a thrombus to form in atrial fibrillation is the left atrial appendage (LAA), due to blood stasis. A persistent filling defect on delayed imaging (which rules out slow flow) is diagnostic of a thrombus.
  • Why (A) is wrong: A myxoma arises from the interatrial septum, not the appendage.
  • Why (C) is wrong: Pectinate muscles are normal anatomical ridges within the appendage, but they should enhance with the rest of the myocardium and would not appear as a filling defect on delayed images.
  • Why (D) is wrong: Incomplete mixing (slow flow) can mimic a thrombus on early-phase images, but it would opacify (fill in) on delayed-phase scans. This defect was persistent.
  • Why (E) is wrong: A metastasis would be a solid, enhancing mass, not a low-attenuation filling defect.

Key Points: Left Atrial Appendage Thrombus

  • Risk Factor: Atrial Fibrillation (due to stasis).
  • Location: The Left Atrial Appendage is the most common site (~90% of thrombi).
  • CT Imaging:
    • A filling defect in the LAA.
    • Delayed-phase imaging is crucial to differentiate from slow-flow artifact (which will fill in). A true thrombus will remain a dark defect.

Question 13: Ventricular Pseudoaneurysm

Stem: A 66-year-old man, 10 days post-inferior MI, presents with acute dyspnoea and a new systolic murmur. A Cardiac MRI reveals a large, contained collection posterior to the LV. This collection communicates with the LV cavity via a defect with a narrow neck. The wall of the collection is formed by the pericardium and does not enhance.

Question: What is the most likely diagnosis?

(A) True Ventricular Aneurysm (B) Ventricular Pseudoaneurysm (C) Papillary Muscle Rupture (D) Ventricular Septal Defect (E) Dressler’s Syndrome

Correct Answer: (B) Ventricular Pseudoaneurysm.

Explanation:

  • Why (B) is correct: This is the classic description of a contained ventricular free wall rupture. It is an acute post-MI complication. The key differentiating feature is the narrow neck (the site of the rupture) relative to the size of the aneurysmal sac. The wall is pericardium, not myocardium. This is a surgical emergency.
  • Why (A) is wrong: A true aneurysm is a late complication with a wide neck and a wall made of thinned myocardium.
  • Why (C) is wrong: Papillary muscle rupture would cause catastrophic mitral regurgitation and a massively dilated left atrium, not a contained posterior collection.
  • Why (D) is wrong: A VSD is a rupture of the septum, which would show a shunt from the LV to the RV, not a posterior collection.
  • Why (E) is wrong: Dressler’s Syndrome is an autoimmune pericarditis, which would present as a pericardial effusion and enhancement, not a pseudoaneurysm.

Key Points: Pseudoaneurysm vs. True Aneurysm

  • Pseudoaneurysm:
    • Time: Acute (days-weeks).
    • Neck: Narrow.
    • Wall: Pericardium.
    • Risk: High risk of rupture.
  • True Aneurysm:
    • Time: Chronic (months-years).
    • Neck: Wide.
    • Wall: Scarred Myocardium.
    • Risk: Low risk of rupture.

Question 14: Malignant Coronary Artery Anomaly

Stem: A 19-year-old basketball player experiences syncope during a game. A CT Coronary Angiogram (CTCA) is performed. It demonstrates that the left main coronary artery arises anomalously from the right coronary cusp. The artery is then seen taking a course between the aorta and the pulmonary artery.

Question: This finding is significant because it is a high-risk feature for:

(A) Early Atherosclerosis (B) Coronary Artery Aneurysm (C) Sudden Cardiac Death (D) Aortic Dissection (E) Pulmonary Hypertension

Correct Answer: (C) Sudden Cardiac Death.

Explanation:

  • Why (C) is correct: An anomalous coronary artery with an interarterial course (passing between the aorta and pulmonary artery) is a “malignant” anomaly. During exercise, the aorta and pulmonary artery expand, compressing the coronary artery and causing acute ischemia and sudden cardiac death.
  • Why (A) is wrong: This anomaly does not cause atherosclerosis.
  • Why (B) is wrong: It is not associated with aneurysms.
  • Why (D) is wrong: It does not cause aortic dissection.
  • Why (E) is wrong: It does not cause pulmonary hypertension.

Key Points: Anomalous Coronary Arteries

  • “Malignant” Course: Interarterial (between the aorta and pulmonary artery). This is the highest-risk anomaly.
  • “Benign” Courses:
    • Retroaortic (behind the aorta).
    • Pre-pulmonic (in front of the pulmonary artery).
    • Septal (through the interventricular septum).
  • Significance: Malignant interarterial course is a leading cause of exercise-induced sudden cardiac death in young people.

Question 15: Dilated Cardiomyopathy (DCM)

Stem: A 48-year-old man with a long history of heavy alcohol use presents with severe, progressive heart failure. A Cardiac MRI shows global four-chamber dilatation and severe biventricular systolic dysfunction (LVEF 25%). There is no LGE to suggest ischemia, but faint linear LGE is noted in the mid-wall of the interventricular septum.

Question: What is the most likely diagnosis?

(A) Ischemic Cardiomyopathy (B) Hypertrophic Cardiomyopathy (C) Dilated Cardiomyopathy (DCM) (D) Restrictive Cardiomyopathy (E) Constrictive Pericarditis

Correct Answer: (C) Dilated Cardiomyopathy (DCM).

Explanation:

  • Why (C) is correct: The key finding is global dilatation and severe systolic dysfunction (a “big, baggy heart”). The absence of ischemic-pattern LGE (subendocardial) rules out ischemia. The faint mid-wall septal LGE is a non-specific sign of fibrosis, commonly seen in DCM. Alcohol is a well-known toxin that causes DCM.
  • Why (A) is wrong: Ischemic cardiomyopathy is a common cause of a dilated heart, but it would always have subendocardial LGE.
  • Why (B) is wrong: HCM is characterized by a thick, non-dilated ventricle.
  • Why (D) is wrong: Restrictive cardiomyopathy is a disease of stiff ventricles, which are normal-sized or thick (not dilated), with massive bi-atrial enlargement.
  • Why (E) is wrong: Constrictive pericarditis is a pericardial disease, and the ventricles would be normal-sized and “tethered”.

Key Points: Dilated Cardiomyopathy (DCM)

  • Pathology: A disease of systolic dysfunction, leading to progressive dilatation of the ventricles.
  • Causes: Idiopathic, alcoholic, post-viral, genetic.
  • CMR Findings:
    • LV and/or RV dilatation.
    • Global systolic dysfunction (low ejection fraction).
    • LGE: Often absent. If present, it is typically linear, non-vascular mid-wall enhancement, especially in the septum.

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