📝 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:
A 7-year-old child with an atrial septal defect has enlargement of the right atrium and right ventricle. Which hemodynamic disturbance best explains these changes?

Options:
Pressure overload from systemic hypertension
Volume overload from increased atrial shunting
Reduced blood return from the pulmonary veins
Obstruction at the left ventricular outflow
Regurgitation through the mitral valve

Correct Answer:
Volume overload from increased atrial shunting

Explanation:
An ASD produces a left-to-right atrial shunt, increasing right atrial and right ventricular filling and causing right-sided volume overload.

MCQ 2

Question:
A child with a large ventricular septal defect has tachypnea and hepatomegaly. Which circulation receives the initial excess volume responsible for these symptoms?

Options:
Coronary circulation
Systemic venous circulation
Cerebral circulation
Pulmonary circulation
Portal circulation

Correct Answer:
Pulmonary circulation

Explanation:
A large VSD directs blood from the left ventricle to the right ventricle, increasing pulmonary blood flow and producing heart failure symptoms.

MCQ 3

Question:
A cyanotic infant has a ventricular septal defect, an overriding aorta and marked narrowing of the right ventricular outflow tract. Which physiological consequence follows directly from this combination?

Options:
Systemic delivery of poorly oxygenated blood
Marked increase in pulmonary venous pressure
Isolated left atrial volume overload
Complete separation of both circulations
Reduced pressure within the right ventricle

Correct Answer:
Systemic delivery of poorly oxygenated blood

Explanation:
Right ventricular outflow obstruction diverts deoxygenated blood across the VSD into the overriding aorta, producing systemic cyanosis.

MCQ 4

Question:
A child with an atrial septal defect has persistent splitting of the second heart sound during both inspiration and expiration. Which mechanism best explains this finding?

Options:
Early closure of the pulmonary valve
Delayed closure of the aortic valve
Reduced venous return during inspiration
Premature right ventricular contraction
Persistently increased right ventricular stroke volume

Correct Answer:
Persistently increased right ventricular stroke volume

Explanation:
Continuous right ventricular volume loading delays pulmonary valve closure, making the split second heart sound wide and relatively fixed.

MCQ 5

Question:
A child with a ventricular septal defect has dilation of the left atrium and left ventricle. Which mechanism produces this chamber pattern?

Options:
Direct transfer of blood into the left atrium
Reduced systemic venous return
Increased pulmonary venous return
Obstruction of right ventricular inflow
Reduced blood flow through the lungs

Correct Answer:
Increased pulmonary venous return

Explanation:
The left-to-right shunt increases pulmonary flow, which returns to the left atrium and left ventricle and produces left-sided volume overload.

MCQ 6

Question:
A child with severe pulmonary valve stenosis develops exertional dizziness. Which pathological change is most likely responsible for the reduced ability to increase cardiac output?

Options:
Fixed obstruction to right ventricular ejection
Excessive flow through an atrial defect
Progressive dilation of the left ventricle
Increased compliance of the pulmonary valve
Reduced resistance in the systemic circulation

Correct Answer:
Fixed obstruction to right ventricular ejection

Explanation:
Pulmonary stenosis limits right ventricular output, particularly during exercise, and may cause exertional dizziness or syncope.

MCQ 7

Question:
A child with Tetralogy of Fallot has chronic hypoxemia and an elevated hematocrit. Which physiological stimulus is responsible for this response?

Options:
Increased platelet destruction
Reduced iron absorption
Suppression of bone marrow activity
Enhanced erythropoietic drive
Loss of plasma proteins

Correct Answer:
Enhanced erythropoietic drive

Explanation:
Chronic hypoxemia stimulates erythropoiesis, producing secondary polycythemia as a compensatory response.

MCQ 8

Question:
A 10-year-old child with a long-standing atrial septal defect develops palpitations. Which structural alteration most strongly predisposes to this symptom?

Options:
Left ventricular wall thinning
Right atrial dilation
Pulmonary valve calcification
Aortic root narrowing
Left atrial fibrosis alone

Correct Answer:
Right atrial dilation

Explanation:
Chronic right atrial volume overload in ASD may predispose to atrial arrhythmias and palpitations.

MCQ 9

Question:
A child with severe right ventricular outflow obstruction has no central cyanosis. Which additional feature is most likely absent?

Options:
Right ventricular hypertrophy
Ejection systolic murmur
Post-stenotic arterial dilation
Exercise intolerance
A pathway for right-to-left shunting

Correct Answer:
A pathway for right-to-left shunting

Explanation:
Obstruction alone causes pressure overload but not cyanosis unless a communication allows deoxygenated blood to enter systemic circulation.

MCQ 10

Question:
An infant with a large ventricular septal defect develops repeated respiratory infections. Which mechanism best explains this association?

Options:
Reduced pulmonary perfusion
Right-to-left systemic shunting
Pulmonary overcirculation and congestion
Obstruction of pulmonary venous drainage
Reduced bronchial blood supply

Correct Answer:
Pulmonary overcirculation and congestion

Explanation:
Excessive pulmonary blood flow promotes congestion and respiratory symptoms, increasing susceptibility to recurrent chest infections.

MCQ 11

Question:
A child with Tetralogy of Fallot has marked cyanosis but no signs of pulmonary congestion. Which finding best explains this combination?

Options:
Increased pulmonary venous pressure
Reduced pulmonary blood flow
Severe left ventricular failure
Large left-to-right atrial shunt
Mitral valve obstruction

Correct Answer:
Reduced pulmonary blood flow

Explanation:
Pulmonary outflow obstruction limits blood entering the lungs while promoting right-to-left shunting, causing cyanosis without pulmonary congestion.

MCQ 12

Question:
A child with a congenital cardiac murmur has no cyanosis, but echocardiography shows marked right ventricular hypertrophy without chamber dilation. Which lesion is most consistent with this pattern?

Options:
Large atrial septal defect
Large ventricular septal defect
Patent ductus arteriosus
Pulmonary stenosis
Tetralogy of Fallot with severe shunting

Correct Answer:
Pulmonary stenosis

Explanation:
Isolated pulmonary stenosis produces pressure overload and concentric right ventricular hypertrophy rather than primary volume dilation.

MCQ 13

Question:
A previously asymptomatic child with a small ventricular septal defect is found to have a palpable precordial thrill. Which feature of blood flow is responsible?

Options:
High-velocity passage through a restrictive opening
Equal ventricular pressure throughout systole
Reduced ventricular contractility
Complete absence of a pressure gradient
Minimal turbulence across the defect

Correct Answer:
High-velocity passage through a restrictive opening

Explanation:
A small restrictive VSD creates a high pressure gradient and marked turbulence, producing a loud murmur and sometimes a palpable thrill.

MCQ 14

Question:
A child with congenital heart disease develops clubbing several years after initially presenting without cyanosis. Which change most likely preceded the clubbing?

Options:
Spontaneous reduction in pulmonary pressure
Closure of the cardiac communication
Improved pulmonary arterial compliance
Reduction of systemic vascular resistance
Reversal of the direction of shunting

Correct Answer:
Reversal of the direction of shunting

Explanation:
Pulmonary hypertension may reverse an initial left-to-right shunt, causing chronic systemic desaturation, cyanosis and clubbing.

MCQ 15

Question:
A child with pulmonary valve stenosis has a prominent right ventricular heave on examination. Which anatomical change underlies this finding?

Options:
Right atrial volume overload
Left ventricular dilation
Thickening of right ventricular myocardium
Pulmonary venous congestion
Aortic root enlargement

Correct Answer:
Thickening of right ventricular myocardium

Explanation:
Chronic pressure overload causes right ventricular hypertrophy, which produces a palpable parasternal heave.

MCQ 16

Question:
A child with congenital heart disease has central cyanosis from birth. Which lesion is least compatible with this presentation in its uncomplicated form?

Options:
Tetralogy of Fallot
Tricuspid atresia
Transposition of great arteries
Atrial septal defect
Pulmonary atresia

Correct Answer:
Atrial septal defect

Explanation:
An uncomplicated ASD produces an acyanotic left-to-right shunt; early central cyanosis suggests a right-to-left shunt or abnormal mixing lesion.

MCQ 17

Question:
A child with a large VSD has developed severe pulmonary hypertension. Which cardiac chamber is expected to show increasing pressure-related hypertrophy at this stage?

Options:
Left atrium
Right ventricle
Left ventricle
Right atrium alone
Coronary sinus

Correct Answer:
Right ventricle

Explanation:
Pulmonary hypertension increases right ventricular afterload, resulting in progressive right ventricular hypertrophy.

MCQ 18

Question:
A pregnant woman with poorly controlled diabetes asks about fetal cardiac risk. Which step in disease causation is most relevant?

Options:
Disturbance of embryonic cardiovascular development
Postnatal bacterial injury of cardiac valves
Autoimmune destruction of ventricular muscle
Childhood pulmonary vascular thrombosis
Acquired obstruction of the outflow tract

Correct Answer:
Disturbance of embryonic cardiovascular development

Explanation:
Maternal diabetes is a recognized risk factor for congenital malformations through abnormal development of the fetal cardiovascular system.

MCQ 19

Question:
A child with suspected congenital heart disease has a normal chest radiograph but persistent cyanosis. Which investigation would provide the most useful next anatomical information?

Options:
Serum troponin level
Complete blood count
Arterial blood gas alone
Chest computed tomography without contrast
Echocardiography with Doppler assessment

Correct Answer:
Echocardiography with Doppler assessment

Explanation:
Echocardiography directly identifies structural defects, estimates gradients and demonstrates the direction of intracardiac blood flow.

MCQ 20

Question:
A child with Tetralogy of Fallot develops sudden worsening of cyanosis while crying. Which physiological change would most strongly worsen the episode?

Options:
Increase in systemic vascular resistance
Reduction in right ventricular contractility
Fall in systemic vascular resistance
Increase in pulmonary blood flow
Reduction in right-to-left shunting

Correct Answer:
Fall in systemic vascular resistance

Explanation:
A fall in systemic vascular resistance favors greater right-to-left shunting across the VSD and worsens systemic hypoxemia during a tet spell.

📌 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.