📝 Step 5 — KMU Past Papers & Exam Learning

This section contains KMU-style past paper questions designed to strengthen conceptual understanding. Focus on understanding explanations rather than memorizing answers.

🎯 How to Study KMU Past Papers

• Read the question carefully.
• Think about the answer before looking.
• Read the explanation slowly.
• Understand the reasoning behind the correct answer.
• Revise difficult questions again.

MCQ 1

Question:
During inspiration, physiological splitting of the second heart sound becomes more prominent. Which change is mainly responsible?

Options:

Increased left ventricular filling delays aortic closure
Prolonged right ventricular ejection delays pulmonary closure
Reduced venous return advances tricuspid valve closure
Raised aortic pressure delays mitral valve opening
Reduced pulmonary flow advances pulmonary valve closure

Correct Answer:
Prolonged right ventricular ejection delays pulmonary closure

Explanation:
Inspiration increases venous return to the right heart, prolonging right ventricular ejection and delaying P2 relative to A2.

MCQ 2

Question:
A patient with severe aortic stenosis develops atrial fibrillation. Which additional heart sound is expected to disappear?

Options:

First heart sound
Second heart sound
Third heart sound
Fourth heart sound
Opening snap

Correct Answer:
Fourth heart sound

Explanation:
S4 requires effective atrial contraction against a stiff hypertrophied ventricle. It disappears when coordinated atrial contraction is lost.

MCQ 3

Question:
A patient has a pansystolic apical murmur. The murmur becomes louder during sustained handgrip. What is the best explanation?

Options:

Increased afterload promotes backward flow into the left atrium
Reduced venous return increases flow through the mitral valve
Decreased arterial pressure increases forward ventricular ejection
Reduced left atrial pressure widens the regurgitant orifice
Increased contractility reduces the ventricular–atrial gradient

Correct Answer:
Increased afterload promotes backward flow into the left atrium

Explanation:
Handgrip increases systemic vascular resistance. The greater left ventricular afterload increases mitral regurgitant flow and murmur intensity.

MCQ 4

Question:
A woman with long-standing mitral stenosis develops persistent hoarseness. Which structure is most likely being compressed?

Options:

Right phrenic nerve
Left sympathetic chain
Right recurrent laryngeal nerve
Left vagus nerve
Left recurrent laryngeal nerve

Correct Answer:
Left recurrent laryngeal nerve

Explanation:
A markedly enlarged left atrium may compress the left recurrent laryngeal nerve, producing Ortner syndrome.

MCQ 5

Question:
A patient with severe mitral stenosis presents with episodes of blood-streaked sputum. What is the most likely underlying mechanism?

Options:

Necrosis of pulmonary valve cusps
Embolization into bronchial arteries
Rupture of vessels from pulmonary venous hypertension
Immune-complex injury of alveolar capillaries
Infection of the pulmonary arterial wall

Correct Answer:
Rupture of vessels from pulmonary venous hypertension

Explanation:
Raised left atrial and pulmonary venous pressures can rupture small bronchial veins or pulmonary capillaries, causing hemoptysis.

MCQ 6

Question:
Why is primary left ventricular hypertrophy generally absent in isolated mitral stenosis?

Options:

The ventricle is protected by pulmonary hypertension
The ventricle receives reduced filling without pressure overload
The aortic valve decreases systemic vascular resistance
The left atrium absorbs the full ventricular pressure
The ventricular myocardium undergoes early fibrous atrophy

Correct Answer:
The ventricle receives reduced filling without pressure overload

Explanation:
Mitral stenosis obstructs left ventricular inflow and primarily overloads the left atrium. The left ventricle is underfilled rather than pressure-loaded.

MCQ 7

Question:
A 48-year-old man develops calcific aortic stenosis at a younger age than expected. Echocardiography shows a congenitally bicuspid valve. What accelerated the degeneration?

Options:

Chronic immune-complex deposition
Repeated bacterial colonization
Progressive commissural fusion
Abnormal mechanical stress on the cusps
Reduced calcium deposition within the valve

Correct Answer:
Abnormal mechanical stress on the cusps

Explanation:
A bicuspid valve experiences abnormal flow and mechanical stress, leading to earlier cusp degeneration and calcification.

MCQ 8

Question:
A patient with severe aortic stenosis develops exertional angina despite normal coronary arteries. Which mechanism best explains this symptom?

Options:

Increased myocardial oxygen demand with impaired subendocardial perfusion
Reduced right ventricular filling with coronary vasodilatation
Regurgitant flow from the aorta into the ventricle
Coronary embolization from a left atrial thrombus
Reduced pulmonary venous pressure during exercise

Correct Answer:
Increased myocardial oxygen demand with impaired subendocardial perfusion

Explanation:
Concentric hypertrophy increases oxygen demand, while high intraventricular pressure and reduced diastolic perfusion impair myocardial oxygen supply.

MCQ 9

Question:
A patient with chronic mitral regurgitation remains mildly symptomatic despite a large regurgitant volume. Which adaptation best explains the initial compensation?

Options:

Concentric hypertrophy of the right ventricle
Reduced compliance of the left ventricle
Early closure of the aortic valve
Increased systemic arterial resistance
Progressive dilatation and compliance of the left atrium

Correct Answer:
Progressive dilatation and compliance of the left atrium

Explanation:
A dilated, compliant left atrium initially accommodates the regurgitant volume with a smaller rise in atrial and pulmonary venous pressure.

MCQ 10

Question:
A patient develops acute severe mitral regurgitation after chordal rupture. The murmur is shorter and less intense than expected. What is the best explanation?

Options:

The regurgitant orifice closes in late systole
The left ventricle ejects only into the aorta
The ventricular and atrial pressures equalize rapidly
The left atrium has developed marked compliance
The mitral valve opens during ventricular systole

Correct Answer:
The ventricular and atrial pressures equalize rapidly

Explanation:
In acute severe regurgitation, left atrial pressure rises rapidly, reducing the ventricular–atrial pressure gradient before systole ends.

MCQ 11

Question:
A child with acute rheumatic fever develops sharp chest pain and a pericardial friction rub. Which pathological appearance is most likely?

Options:

Caseous material covering the pericium
Purulent exudate filling the pericardial sac
Calcified plaques over the epicardial surface
Fibrinous “bread-and-butter” pericarditis
Hemorrhagic fluid caused by valve rupture

Correct Answer:
Fibrinous “bread-and-butter” pericarditis

Explanation:
Acute rheumatic pancarditis may involve the pericardium and produce a fibrinous exudate with a rough bread-and-butter appearance.

MCQ 12

Question:
A myocardial biopsy from a child with acute rheumatic carditis shows macrophages with centrally placed wavy chromatin. What are these cells called?

Options:

Reed–Sternberg cells
Anitschkow cells
Langhans giant cells
Aschoff giant cells
Touton giant cells

Correct Answer:
Anitschkow cells

Explanation:
Anitschkow cells are activated macrophages with characteristic “caterpillar” nuclear chromatin found within Aschoff bodies.

MCQ 13

Question:
A child has an elevated antistreptolysin O titre but no clinical Jones manifestations. Which interpretation is most appropriate?

Options:

The child has active rheumatic carditis
The child has chronic rheumatic valve disease
The child requires a diagnosis of recurrent rheumatic fever
The titre determines the severity of myocardial inflammation
The result supports recent streptococcal exposure only

Correct Answer:
The result supports recent streptococcal exposure only

Explanation:
An elevated ASO titre indicates a recent immune response to streptococcal infection but does not independently diagnose rheumatic fever or carditis.

MCQ 14

Question:
A patient with suspected infective endocarditis has repeatedly negative blood cultures. He received oral antibiotics before admission. What is the most likely explanation?

Options:

Antimicrobial exposure has suppressed circulating organisms
The vegetations must be nonbacterial thrombotic lesions
The infection is confined entirely to the myocardium
The endocardial lesion cannot release organisms
The valve disease is caused by rheumatic immunity

Correct Answer:
Antimicrobial exposure has suppressed circulating organisms

Explanation:
Antibiotics given before blood sampling can reduce or eliminate detectable bacteremia, producing culture-negative infective endocarditis.

MCQ 15

Question:
A patient with infective endocarditis develops painful tender nodules on the fingertips. Which mechanism best explains these lesions?

Options:

Calcific emboli from a stenotic valve
Direct extension of infection through the skin
Immune-mediated vascular injury
Chronic venous congestion of the fingers
Reduced arterial flow from heart failure

Correct Answer:
Immune-mediated vascular injury

Explanation:
Osler nodes are painful lesions associated mainly with immunological vascular injury. Janeway lesions are painless and more closely linked with septic microemboli.

MCQ 16

Question:
A patient with a prosthetic heart valve develops indolent infective endocarditis. Which organism is an important cause in this setting?

Options:

Streptococcus pyogenes
Coagulase-negative staphylococci
Streptococcus pneumoniae
Neisseria meningitidis
Corynebacterium diphtheriae

Correct Answer:
Coagulase-negative staphylococci

Explanation:
Coagulase-negative staphylococci can adhere to prosthetic material and are important causes of prosthetic valve endocarditis.

MCQ 17

Question:
An 8-year-old child has confirmed group A streptococcal pharyngitis and no penicillin allergy. Which intervention best prevents the first attack of rheumatic fever?

Options:

Monthly echocardiographic surveillance
Long-term aspirin therapy
Antibiotics before dental procedures
Delayed treatment if joint symptoms develop
Completion of an appropriate penicillin course

Correct Answer:
Completion of an appropriate penicillin course

Explanation:
Primary prophylaxis consists of prompt and adequate treatment of confirmed GAS pharyngitis, commonly with penicillin or amoxicillin.

MCQ 18

Question:
A patient has persistent fever, a prosthetic valve and clinical features strongly suggesting infective endocarditis. Transthoracic echocardiography is negative. What is the most appropriate next investigation?

Options:

Exercise stress echocardiography
Repeat electrocardiography after one week
Computed tomography of the coronary arteries
Transesophageal echocardiography
Twenty-four-hour ambulatory blood pressure monitoring

Correct Answer:
Transesophageal echocardiography

Explanation:
Transesophageal echocardiography is more sensitive for prosthetic valve vegetations, perivalvular abscesses and cases with high suspicion despite negative transthoracic imaging.

MCQ 19

Question:
Histological examination of a valve vegetation shows fibrin, platelets, numerous bacterial colonies and necrotic debris. Which diagnosis is most likely?

Options:

Infective endocarditis
Rheumatic valvulitis
Libman–Sacks endocarditis
Nonbacterial thrombotic endocarditis
Degenerative calcific valve disease

Correct Answer:
Infective endocarditis

Explanation:
Infective vegetations contain microorganisms within platelet-fibrin material and are associated with necrosis, inflammation and valve destruction.

MCQ 20

Question:
A patient with native rheumatic mitral disease asks whether antibiotics are required before every dental procedure. Which response is most appropriate?

Options:

All native valve lesions require procedure-related prophylaxis
Monthly benzathine penicillin provides dental prophylaxis
Native rheumatic disease alone is not a highest-risk indication
Every murmur requires antibiotics before dental manipulation
Previous streptococcal pharyngitis is sufficient indication

Correct Answer:
Native rheumatic disease alone is not a highest-risk indication

Explanation:
Routine infective-endocarditis prophylaxis is not given solely for native rheumatic valve disease; it is reserved for selected highest-risk cardiac conditions.

.

📌 Important Exam Strategy

KMU examinations often test integrated understanding rather than isolated facts. Focus on linking anatomy, embryology, histology, and clinical concepts when reviewing questions.

✅ Revision Tip

If you can explain the reason behind the correct answer without looking at notes, your concept is strong.