MCQ: Cardiovascular System Pathology

Question 1

Which foramen ovale closes in approximately 75% of individuals at birth?

Accepted Answer

Foramen ovale — Closes by fusion of septum primum and secundum. Persists in 25% of adults as PFO. ---

Question 2

Anatomical closure of the ductus arteriosus occurs through which process?

Accepted Answer

Intimal proliferation and fibrosis — Functional closure via vasoconstriction occurs first. Anatomical closure takes several weeks through intimal proliferation and fibrosis. ---

Question 3

Failure of which structure to adequately cover the ostium secundum results in ostium secundum ASD?

Accepted Answer

Septum secundum — Ostium secundum ASD occurs when the septum secundum does not enlarge sufficiently to cover the ostium secundum. ---

Question 4

Which VSD type is specifically more common in Asian patients?

Accepted Answer

Doubly committed subarterial VSD — Situated in the outlet septum, bordered by fibrous continuity of aortic and pulmonary valves. ---

Question 5

The fundamental embryological defect in Tetralogy of Fallot is

Accepted Answer

Anterior cephalad deviation of the outlet septum — This single defect produces all four features of TOF — outlet VSD, pulmonary outflow obstruction, overriding aorta and RVH. ---

Question 6

Which structure, when displaced apically, causes atrialization of the right ventricular inflow tract?

Accepted Answer

Septal leaflet of tricuspid valve — This is Ebstein's anomaly. Apical displacement of the septal tricuspid leaflet causes the RV inflow to function as an atrial chamber. ---

Question 7

In Transposition of Great Arteries, which embryological failure is directly responsible?

Accepted Answer

Resorption of subpulmonary instead of subaortic conus — Normally the subaortic conus resorbs, moving the aorta posteriorly to connect with the LV. In TGA the wrong conus resorbs, keeping the aorta anterior and connected to the RV. ---

Question 8

Which chromosomal abnormality is most specifically associated with coarctation of the aorta?

Accepted Answer

Turner syndrome — Turner syndrome is specifically associated with coarctation of aorta and bicuspid aortic valve. Trisomy 21 is associated with AV canal defects. ---

Question 9

Persistent truncus arteriosus always occurs alongside which other defect?

Accepted Answer

Ventricular septal defect — The single great vessel overrides both ventricles, so a VSD is always present in persistent truncus arteriosus. ---

Question 10

Sinus venosus ASD is specifically associated with anomalous drainage of pulmonary veins from which lung?

Accepted Answer

Right lung — Right pulmonary veins drain anomalously into the SVC or right atrium due to the proximity of the sinus venosus defect to the SVC entry. ---

Question 11

Which maternal teratogen is specifically associated with Ebstein's anomaly?

Accepted Answer

Lithium — Maternal lithium use in first trimester is the specific teratogen classically associated with Ebstein's anomaly. ---

Question 12

A restrictive VSD differs from a non-restrictive VSD in that it

Accepted Answer

May close spontaneously during childhood — Restrictive VSDs cause no significant haemodynamic derangement and may close spontaneously, unlike large non-restrictive VSDs which cause progressive pulmonary hypertension. ---

Question 13

Which congenital defect results from failure of both subpulmonary AND subaortic conus to resorb?

Accepted Answer

Double outlet right ventricle — Failure of either conus to resorb produces double outlet anomalies of the RV. TGA results from resorption of the wrong conus. TOF results from malalignment, not failure of resorption. ---

Question 14

The ostium primum is created during atrial septation by growth of which structure toward the AV canal?

Accepted Answer

Septum primum downward from the roof — The septum primum grows downward creating the ostium primum inferiorly. As it grows, perforations form superiorly creating the ostium secundum. ---

Question 15

VSD accounts for what percentage of all congenital heart disease?

Accepted Answer

25% — VSD is the most common congenital heart defect overall, accounting for 25% of all CHD. ---

Question 16

Which component of the ventricular septum lies directly beneath the aortic valve?

Accepted Answer

Membranous septum — The small membranous septum lies just underneath the aortic valve. Membranous VSDs often have inlet, outlet or trabecular extension. ---

Question 17

In which CHD does the right ventricle inflow tract function haemodynamically as an atrial chamber?

Accepted Answer

Ebstein's anomaly — Apical displacement of the septal tricuspid leaflet causes atrialization of the RV inflow tract — it receives atrial pressure and contracts out of synchrony with the functional RV. ---

Question 18

Which of the following is the correct sequence of atrial septal development?

Accepted Answer

Septum primum → ostium primum → ostium secundum → septum secundum — Septum primum grows down creating ostium primum. Perforations coalesce into ostium secundum. Then septum secundum develops to the right, leaving the fossa ovalis. ---

Question 19

Which of the following maternal infections is a recognised cause of congenital heart disease?

Accepted Answer

Rubella — Maternal rubella is a recognised environmental cause of CHD, particularly PDA and pulmonary stenosis. It is specifically listed among the environmental teratogenic causes of CHD. ---

Question 20

In Tetralogy of Fallot, which level is the dominant site of right ventricular outflow obstruction?

Accepted Answer

Subvalvular (infundibular) — The dominant obstruction in TOF is at the subvalvular/infundibular level due to hypertrophied infundibular myocardium from the malaligned outlet septum — not at the valve itself. ---

Question 21

Coarctation of the aorta occurs most commonly at which location?

Accepted Answer

Juxtaductal — at the ductus arteriosus insertion — Narrowing occurs just distal to the left subclavian artery at the site of ductus arteriosus insertion. ---

Question 22

Which radiological finding is specifically associated with coarctation of the aorta?

Accepted Answer

Rib notching — Caused by dilated intercostal collateral vessels eroding the inferior rib margins, developing to bypass the coarctation. ---

Question 23

A patient with an untreated large VSD develops reversed cyanosis. Which term describes this end-stage complication?

Accepted Answer

Eisenmenger syndrome — Chronic L→R shunting → pulmonary hypertension → pulmonary pressure exceeds systemic → shunt reverses to R→L → cyanosis. This is irreversible. ---

Question 24

Patent foramen ovale in adults is specifically associated with which cerebrovascular complication?

Accepted Answer

Paradoxical embolism causing cryptogenic stroke — Venous thrombus crosses from right to left atrium through the PFO entering systemic circulation, causing stroke without an obvious arterial source. ---

Question 25

Ostium primum ASD is associated with a cleft in which specific valve leaflet?

Accepted Answer

Anterior mitral valve leaflet — Both the ostium primum ASD and the cleft mitral leaflet result from the same endocardial cushion maldevelopment. Commonly seen in Down syndrome. ---

Question 26

Which congenital heart defect is characterised by absence of a direct connection between the right atrium and right ventricle?

Accepted Answer

Tricuspid atresia — There is no tricuspid valve orifice connecting RA to RV. Survival depends on an ASD for right-sided drainage and a VSD or PDA for pulmonary blood flow. ---

Question 27

Hypoplastic left heart syndrome is more common in which sex?

Accepted Answer

Males — Hypoplastic left heart is among the CHDs more common in males, alongside aortic stenosis, coarctation, pulmonary atresia, tricuspid atresia and TGA.

MCQ: Cardiovascular System Pathology

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