📝 Step 6 — 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 newborn begins breathing immediately after delivery. Which pressure change is most important for functional closure of the interatrial fetal communication?
Options:
Rise in right atrial pressure
Rise in pulmonary arterial pressure
Rise in left atrial pressure
Fall in systemic arterial pressure
Fall in left ventricular pressure
Correct Answer:
Rise in left atrial pressure
Explanation:
Lung expansion increases pulmonary venous return, raising left atrial pressure and functionally closing the foramen ovale.
MCQ 2
Question:
A fetus depends on placental oxygenation. Which pathway allows highly oxygenated blood to reach the left side of the heart most efficiently?
Options:
Right atrium → right ventricle → pulmonary trunk
Inferior vena cava → right atrium → foramen ovale
Superior vena cava → right atrium → coronary sinus
Pulmonary trunk → ductus arteriosus → aorta
Umbilical arteries → placenta → umbilical vein
Correct Answer:
Inferior vena cava → right atrium → foramen ovale
Explanation:
Oxygen-rich blood from the IVC is preferentially directed through the foramen ovale to the left atrium.
MCQ 3
Question:
A premature infant has failure of a fetal arterial channel to close. Which physiological factor is most directly responsible for normal closure of this channel?
Options:
Reduced fetal hemoglobin level
Increased oxygen tension
Increased venous return to right atrium
Reduced pulmonary venous return
Increased placental resistance
Correct Answer:
Increased oxygen tension
Explanation:
After birth, increased oxygen tension promotes constriction of the ductus arteriosus.
MCQ 4
Question:
A child with a congenital cardiac defect has recurrent chest infections and signs of pulmonary overcirculation but no early cyanosis. Which type of shunt best explains this presentation?
Options:
Right-to-left atrial shunt
Right-to-left ventricular shunt
Left-to-right cardiac shunt
Pulmonary-to-systemic venous shunt
Systemic-to-coronary arterial shunt
Correct Answer:
Left-to-right cardiac shunt
Explanation:
Left-to-right shunts increase pulmonary blood flow and usually remain acyanotic early.
MCQ 5
Question:
A neonate has severe cyanosis soon after birth. Survival depends on mixing between pulmonary and systemic circuits. Which embryological error is most likely involved?
Options:
Failure of endocardial cushion fusion
Defective spiral septum formation
Incomplete closure of septum primum
Persistence of sinus venosus valve
Delayed closure of umbilical vein
Correct Answer:
Defective spiral septum formation
Explanation:
Transposition of great vessels results from abnormal spiral septum formation and produces parallel circulations.
MCQ 6
Question:
A congenital defect causes high-pressure blood to pass during systole into a lower-pressure chamber. Which consequence is expected if the defect is large?
Options:
Reduced pulmonary venous return
Increased pulmonary blood flow
Reduced left atrial filling
Decreased right ventricular workload
Immediate systemic desaturation
Correct Answer:
Increased pulmonary blood flow
Explanation:
A large VSD allows left ventricular blood to enter the right ventricle, increasing pulmonary flow.
MCQ 7
Question:
A baby with cyanotic spells improves temporarily on squatting. Which hemodynamic effect explains this improvement?
Options:
Reduced pulmonary venous pressure
Increased systemic vascular resistance
Reduced left ventricular afterload
Increased ductus arteriosus flow
Reduced right atrial filling
Correct Answer:
Increased systemic vascular resistance
Explanation:
Squatting increases systemic resistance, reducing right-to-left shunting in Tetralogy of Fallot.
MCQ 8
Question:
In fetal life, pulmonary blood flow remains low mainly because of:
Options:
Low pulmonary vascular resistance
High pulmonary vascular resistance
High left atrial pressure
Early closure of ductus arteriosus
High pulmonary venous return
Correct Answer:
High pulmonary vascular resistance
Explanation:
Collapsed fluid-filled fetal lungs have high vascular resistance, so most blood bypasses them.
MCQ 9
Question:
A neonate develops respiratory distress due to excessive pulmonary blood flow from a persistent fetal connection. Which vessel is directly involved?
Options:
Pulmonary vein
Umbilical artery
Ductus arteriosus
Coronary sinus
Ductus venosus
Correct Answer:
Ductus arteriosus
Explanation:
Persistence of the ductus arteriosus allows aortic blood to enter pulmonary circulation.
MCQ 10
Question:
Which developmental abnormality best explains an atrial septal defect?
Options:
Failure of spiral septum rotation
Failure of septal tissue approximation
Failure of truncus arteriosus division
Failure of pulmonary valve canalization
Failure of aortic arch regression
Correct Answer:
Failure of septal tissue approximation
Explanation:
ASD commonly results from abnormal development or fusion of atrial septal components.
MCQ 11
Question:
A newborn has separate systemic and pulmonary circuits. Which associated defect would be most helpful for short-term survival?
Options:
Mitral valve stenosis
Closed ductus arteriosus
Patent ductus arteriosus
Closed foramen ovale
Pulmonary valve agenesis
Correct Answer:
Patent ductus arteriosus
Explanation:
In transposition, PDA permits mixing of blood between the two parallel circulations.
MCQ 12
Question:
Which circulatory event directly follows clamping of the umbilical cord?
Options:
Fall in placental venous return
Rise in placental oxygen exchange
Rise in right atrial filling
Fall in systemic vascular resistance
Opening of ductus venosus
Correct Answer:
Fall in placental venous return
Explanation:
Cord clamping removes placental circulation, reducing venous return through the umbilical vein.
MCQ 13
Question:
A child with long-standing left-to-right shunt later develops cyanosis. What is the most likely underlying mechanism?
Options:
Closure of pulmonary veins
Reversal of shunt direction
Opening of coronary sinus
Regression of right ventricle
Closure of systemic arteries
Correct Answer:
Reversal of shunt direction
Explanation:
Pulmonary hypertension may reverse the shunt, causing deoxygenated blood to enter systemic circulation.
MCQ 14
Question:
Which fetal structure becomes the ligamentum arteriosum after normal postnatal adaptation?
Options:
Ductus arteriosus
Ductus venosus
Foramen ovale
Umbilical vein
Umbilical artery
Correct Answer:
Ductus arteriosus
Explanation:
After closure, ductus arteriosus forms the ligamentum arteriosum.
MCQ 15
Question:
A vascular lesion in an infant enlarges initially and later tends to regress. Which developmental process is most closely related?
Options:
Defective cardiac septation
Excess endothelial proliferation
Abnormal valve cushion fusion
Persistence of fetal shunting
Failure of neural crest migration
Correct Answer:
Excess endothelial proliferation
Explanation:
Hemangioma is a benign vascular lesion caused by proliferation of endothelial cells.
MCQ 16
Question:
Which defect primarily causes cyanosis because deoxygenated blood enters the aorta through a septal communication?
Options:
Small atrial septal defect
Large patent ductus arteriosus
Tetralogy of Fallot
Isolated mild pulmonary stenosis
Small ventricular septal defect
Correct Answer:
Tetralogy of Fallot
Explanation:
In TOF, pulmonary stenosis raises right ventricular pressure and drives blood through VSD into the aorta.
MCQ 17
Question:
A visible superficial red vascular marking is due to persistent dilation of small vessels. Which anomaly best fits this description?
Options:
Telangiectasia
Hemangioma
Patent ductus arteriosus
Atrial septal defect
Ventricular septal defect
Correct Answer:
Telangiectasia
Explanation:
Telangiectasia is dilation of small superficial vessels, producing visible red vascular markings.
MCQ 18
Question:
Which change converts fetal parallel circulation toward adult serial circulation?
Options:
Increase in placental flow
Increase in pulmonary vascular resistance
Decrease in pulmonary blood flow
Closure of fetal shunts
Opening of umbilical vein
Correct Answer:
Closure of fetal shunts
Explanation:
Closure of fetal shunts separates pulmonary and systemic circuits into adult serial circulation.
MCQ 19
Question:
Which abnormality in Tetralogy of Fallot directly produces pressure overload of the right ventricle?
Options:
Overriding aorta
Pulmonary stenosis
Atrial septal defect
Patent ductus venosus
Dilated coronary sinus
Correct Answer:
Pulmonary stenosis
Explanation:
Pulmonary stenosis obstructs right ventricular outflow, causing pressure overload and hypertrophy.
MCQ 20
Question:
Which treatment principle is most appropriate when ductus arteriosus must be kept open temporarily for survival?
Options:
Give prostaglandin E1
Give prostaglandin inhibitor
Give beta blocker only
Give diuretic only
Give anticoagulant therapy
Correct Answer:
Give prostaglandin E1
Explanation:
Prostaglandin E1 maintains ductus arteriosus patency in duct-dependent congenital heart disease.
📌 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.