AIM • KMU Exam Reasoning
KMU Past Paper Practice
Congenital & Structural Heart Disease in Children
Final Year MBBS • 20 A-type Single Best Answer MCQs
MCQ 1
A 5-year-old child with an atrial septal defect is clinically well, but echocardiography shows progressive enlargement of the right atrium and right ventricle. Which finding best explains why intervention may still be considered despite minimal symptoms?
Persistent systemic desaturation
Chronic right-heart volume loading
Severe left ventricular pressure overload
Progressive pulmonary venous obstruction
Reduced systemic venous return
Correct Answer: Chronic right-heart volume loading
Explanation: A significant ASD can remain clinically silent while persistent left-to-right flow progressively dilates the right-sided chambers.
MCQ 2
A 14-year-old with congenital aortic stenosis develops dizziness during running. Resting blood pressure is normal and there is no cyanosis. Which physiological limitation most directly explains the exertional symptom?
Increased pulmonary venous drainage
Right-to-left intracardiac shunting
Excessive systemic venous pooling
Pulmonary arterial overcirculation
Limited increase in cardiac output across the obstruction
Correct Answer: Limited increase in cardiac output across the obstruction
Explanation: Fixed left ventricular outflow obstruction limits the ability to augment systemic blood flow during exercise, producing dizziness or syncope.
MCQ 3
A newborn becomes pale and poorly perfused several days after birth. Upper-limb pulses remain strong while femoral pulses become difficult to feel. Which change most likely precipitated the deterioration?
Reduction in ductal blood flow
Increase in atrial left-to-right shunting
Increase in pulmonary venous return
Development of tricuspid regurgitation
Reduction in pulmonary vascular resistance alone
Correct Answer: Reduction in ductal blood flow
Explanation: Severe neonatal coarctation may depend on ductal flow to maintain distal systemic perfusion; deterioration can occur as the ductus functionally closes.
MCQ 4
A school-aged child undergoes successful repair of coarctation of the aorta. At follow-up, the child is asymptomatic. Which clinical variable remains particularly important to monitor long term?
Serum bilirubin
Pulmonary venous oxygen content
Central venous pressure only
Systemic arterial blood pressure
Right atrial oxygen saturation
Correct Answer: Systemic arterial blood pressure
Explanation: Hypertension can persist or recur after anatomical correction of coarctation, so long-term blood-pressure surveillance remains important.
MCQ 5
An infant with a large left-to-right congenital shunt has tachypnea and poor weight gain. Chest radiography shows cardiomegaly and prominent pulmonary vascular markings. How should the radiographic vascular pattern be interpreted?
Reduced pulmonary venous return
Pulmonary outflow obstruction
Increased pulmonary blood flow
Reduced right ventricular filling
Systemic arterial obstruction
Correct Answer: Increased pulmonary blood flow
Explanation: Prominent pulmonary vascular markings in a child with a major left-to-right shunt reflect pulmonary overcirculation.
MCQ 6
A cyanotic 3-year-old has reduced pulmonary vascular markings on chest radiography. Echocardiography confirms a congenital lesion in which pulmonary blood flow is restricted. Which physiological category best fits this pattern?
Unrestricted left-to-right shunting
Cyanotic disease with reduced pulmonary flow
Pure systemic venous obstruction
Isolated pulmonary venous hypertension
Acyanotic volume-overload disease
Correct Answer: Cyanotic disease with reduced pulmonary flow
Explanation: Reduced vascular markings indicate decreased pulmonary perfusion, a pattern expected in cyanotic lesions with restricted pulmonary blood flow.
MCQ 7
A neonate has marked cyanosis. Pulse oximetry confirms significant hypoxemia, but the clinical team still cannot identify the specific congenital lesion. What is the main limitation of pulse oximetry in this situation?
It cannot detect systemic hypoxemia
It cannot be used in neonates
It directly measures pulmonary artery pressure
It replaces structural cardiac imaging
It identifies hypoxemia but does not define cardiac anatomy
Correct Answer: It identifies hypoxemia but does not define cardiac anatomy
Explanation: Pulse oximetry detects reduced arterial oxygen saturation but cannot determine which structural congenital defect is responsible.
MCQ 8
An infant with suspected congenital heart disease has an ECG showing chamber hypertrophy. The treating team requests echocardiography next. What additional information is echocardiography expected to provide?
Direct visualization of structural anatomy and hemodynamic effects
Confirmation of bacterial respiratory infection
Measurement of hemoglobin concentration
Assessment of renal perfusion alone
Detection of peripheral pulse delay
Correct Answer: Direct visualization of structural anatomy and hemodynamic effects
Explanation: Echocardiography defines cardiac anatomy and demonstrates the functional consequences of the structural lesion, complementing ECG findings.
MCQ 9
A cyanotic infant is found to have total anomalous pulmonary venous connection. Which associated communication is physiologically essential for oxygenated pulmonary venous blood to reach the systemic arterial circulation?
Aortic narrowing
Pulmonary valve obstruction
Interatrial communication
Mitral valve stenosis
Left ventricular outflow obstruction
Correct Answer: Interatrial communication
Explanation: Because pulmonary veins return to the right side in TAPVC, blood must cross an atrial communication to reach the left heart and systemic circulation.
MCQ 10
A neonate with Ebstein anomaly has a markedly enlarged right atrium on echocardiography. Which structural abnormality most directly produces this chamber abnormality?
Failure of pulmonary veins to reach the left atrium
Single arterial trunk leaving the ventricles
Complete absence of the tricuspid valve opening
Downward displacement of the tricuspid valve
Narrowing of the descending thoracic aorta
Correct Answer: Downward displacement of the tricuspid valve
Explanation: Apical displacement of the tricuspid valve “atrializes” part of the right ventricle and is associated with marked right atrial enlargement and regurgitation.
MCQ 11
A newborn with cyanotic congenital heart disease has no effective connection between the right atrium and right ventricle. Which diagnosis best matches this anatomical description?
Ebstein anomaly
Tricuspid atresia
Truncus arteriosus
Total anomalous pulmonary venous connection
Transposition of the great arteries
Correct Answer: Tricuspid atresia
Explanation: Tricuspid atresia is defined by absence of an effective right atrioventricular connection, forcing systemic venous blood to use an alternative intracardiac pathway.
MCQ 12
An infant with congenital heart disease has mild cyanosis and a single common arterial vessel supplying both pulmonary and systemic circulations. Which lesion is most consistent with this anatomy?
Truncus arteriosus
Coarctation of the aorta
Ebstein anomaly
Atrial septal defect
Tricuspid atresia
Correct Answer: Truncus arteriosus
Explanation: Truncus arteriosus has one common arterial trunk supplying systemic, pulmonary and coronary circulations, with mixing of ventricular blood.
MCQ 13
A child with congenital heart disease has tachypnea and hepatomegaly. Oxygen saturation is normal. Which finding would most strongly support heart failure rather than isolated cyanotic physiology?
Persistent central cyanosis alone
Reduced pulmonary vascular markings
Normal feeding with normal weight gain
Isolated clubbing without tachypnea
Poor feeding with sweating and growth failure
Correct Answer: Poor feeding with sweating and growth failure
Explanation: Feeding difficulty, sweating and failure to thrive are important infant manifestations of cardiac failure caused by increased cardiovascular workload.
MCQ 14
A child with suspected congenital heart disease has an ejection systolic murmur and exertional symptoms. Echocardiography shows obstruction at the left ventricular outflow. Which investigation finding would be most consistent with the chronic hemodynamic effect?
Right atrial volume overload
Reduced left ventricular wall thickness
Evidence of left ventricular pressure loading
Isolated pulmonary venous obstruction
Right-to-left atrial shunting
Correct Answer: Evidence of left ventricular pressure loading
Explanation: Aortic outflow obstruction chronically increases left ventricular systolic pressure and produces pressure-loading changes.
MCQ 15
A pediatrician detects central cyanosis in an infant with suspected congenital heart disease. Which subsequent bedside finding would indicate that the disease has begun to affect systemic perfusion as well as oxygenation?
Normal capillary refill
Normal feeding pattern
Normal peripheral temperature
Delayed capillary refill with weak peripheral pulses
Isolated systolic murmur
Correct Answer: Delayed capillary refill with weak peripheral pulses
Explanation: Weak pulses and delayed capillary refill indicate impaired systemic perfusion and identify a more unstable cardiovascular state.
MCQ 16
A child with a surgically corrected congenital heart defect attends follow-up. The parents ask why reassessment is still necessary despite successful anatomical repair. Which explanation is most appropriate?
All repaired defects inevitably recur within childhood
Residual hemodynamic effects or later cardiovascular problems may persist
Follow-up is required only to repeat chest radiography
All physical activity must be permanently prohibited
Clinical examination becomes unnecessary after surgery
Correct Answer: Residual hemodynamic effects or later cardiovascular problems may persist
Explanation: Anatomical correction does not guarantee absence of residual lesions or later complications, so appropriate cardiovascular follow-up remains necessary.
MCQ 17
A child with congenital heart disease has a chest radiograph showing increased heart size and increased pulmonary vascularity. Which broad pathophysiological pattern is most consistent with these findings?
Pulmonary overcirculation from a significant shunt
Severe restriction of pulmonary blood flow
Isolated lower-body arterial obstruction
Parallel circulation without adequate mixing
Isolated tricuspid valve displacement
Correct Answer: Pulmonary overcirculation from a significant shunt
Explanation: Cardiomegaly with prominent pulmonary vascularity suggests increased pulmonary flow and volume loading from a significant left-to-right shunt.
MCQ 18
A cyanotic infant has a congenital lesion in which oxygenated and deoxygenated blood mix before entering a single common arterial outlet. Which physiological consequence would be expected?
Completely normal systemic oxygenation
Complete separation of venous and arterial blood
Selective perfusion of the upper body only
Absence of pulmonary blood flow
Systemic delivery of partially desaturated mixed blood
Correct Answer: Systemic delivery of partially desaturated mixed blood
Explanation: A common arterial outlet receives mixed ventricular blood, so systemic arterial oxygen content is reduced and cyanosis results.
MCQ 19
Parents of an infant with cyanotic congenital heart disease are preparing for discharge after specialist assessment. Which information is most important to ensure safe home care?
The murmur should disappear before follow-up is needed
The child should avoid all feeding during mild breathlessness
Worsening cyanosis, feeding difficulty or breathing distress requires urgent review
Routine follow-up is unnecessary after initial echocardiography
Growth monitoring is unrelated to congenital heart disease
Correct Answer: Worsening cyanosis, feeding difficulty or breathing distress requires urgent review
Explanation: Families should recognize deterioration early; increasing cyanosis, poor feeding and respiratory distress are important warning features requiring reassessment.
MCQ 20
A pediatric resident is assessing a child with possible structural heart disease. The child has a murmur but no cyanosis. Which approach best reflects appropriate diagnostic reasoning?
Assume the lesion is clinically insignificant because cyanosis is absent
Diagnose the specific defect from murmur intensity alone
Request advanced imaging before performing cardiovascular examination
Integrate symptoms, pulses, heart sounds and echocardiographic anatomy
Exclude congenital disease if oxygen saturation is normal
Correct Answer: Integrate symptoms, pulses, heart sounds and echocardiographic anatomy
Explanation: Congenital heart disease is diagnosed by integrating clinical findings with structural and hemodynamic information rather than relying on one isolated sign.
