Valve development US Medical PG Practice Questions and MCQs
Practice US Medical PG questions for Valve development. These multiple choice questions (MCQs) cover important concepts and help you prepare for your exams.
Valve development US Medical PG Question 1: A 38-year-old woman, gravida 2, para 1, at 24 weeks' gestation comes to the physician for a routine prenatal evaluation. She has no history of major medical illness and takes no medications. Fetal ultrasonography shows a cardiac defect resulting from abnormal development of the endocardial cushions. This defect is most likely to result in which of the following?
- A. Transposition of the great vessels
- B. Atrioventricular septal defect (Correct Answer)
- C. Dextrocardia
- D. Patent foramen ovale
- E. Sinus venosus defect
Valve development Explanation: ***Atrioventricular septal defect***
- **Endocardial cushion defects** are a hallmark of atrioventricular septal defects, leading to a common atrioventricular valve and an interatrial and/or interventricular communication.
- This defect commonly presents in individuals with **Down syndrome (Trisomy 21)**, though it can occur in isolation.
*Transposition of the great vessels*
- This defect results from abnormal **spiraling of the conotruncal septum**, not from endocardial cushion malformation.
- It leads to the **aorta arising from the right ventricle** and the **pulmonary artery from the left ventricle**, a circulation incompatible with life without a shunt.
*Dextrocardia*
- **Dextrocardia** is a condition where the heart is located on the right side of the chest, usually due to abnormal embryonic folding, and is not directly caused by endocardial cushion defects.
- It can occur as an isolated finding or as part of a more complex syndrome like **Kartagener syndrome**.
*Patent foramen ovale*
- A **patent foramen ovale** is a common remnant of fetal circulation, occurring when the foramen ovale fails to close after birth.
- It is a defect of the **atrial septum secondary to incomplete fusion between the septum primum and septum secundum**, not an endocardial cushion defect.
*Sinus venosus defect*
- A **sinus venosus defect** is a type of atrial septal defect occurring near the entrance of the superior or inferior vena cava.
- It is caused by **abnormal development of the sinus venosus** and is not directly related to endocardial cushion malformation.
Valve development US Medical PG Question 2: A 67-year-old man presents to his primary care physician for a wellness checkup. The patient states he has been doing well and currently has no concerns. The patient's daughter states that she feels he is abnormally fatigued and has complained of light-headedness whenever he gardens. He also admits that he fainted once. The patient has a past medical history of type II diabetes, hypertension, and constipation. He recently had a "throat cold" that he recovered from with rest and fluids. His temperature is 98.9°F (37.2°C), blood pressure is 167/98 mmHg, pulse is 90/min, respirations are 12/min, and oxygen saturation is 99% on room air. Physical exam reveals a systolic murmur heard best along the right upper sternal border. An ECG is performed and demonstrates no signs of ST elevation. Cardiac troponins are negative. Which of the following is the most likely diagnosis?
- A. Outflow tract obstruction
- B. Calcification of valve leaflets (Correct Answer)
- C. Incompetent valve
- D. Autoimmune valve destruction
- E. Bicuspid valve
Valve development Explanation: ***Calcification of valve leaflets***
- The patient's age (67 years old), symptoms (fatigue, light-headedness, syncope with exertion), and the presence of a **systolic murmur heard best along the right upper sternal border** are classic signs of **aortic stenosis**.
- In elderly patients, **degenerative calcification** of the aortic valve leaflets is the most common cause of aortic stenosis.
*Outflow tract obstruction*
- While aortic stenosis is a form of outflow tract obstruction, this option is too general.
- **Calcification of valve leaflets** is the specific pathological mechanism leading to the obstruction in this patient's age group.
*Incompetent valve*
- An incompetent valve (regurgitation) typically causes a **diastolic murmur** or a holosystolic regurgitant murmur, not the systolic ejection murmur described.
- The symptoms of an incompetent valve can differ, often including signs of volume overload rather than exertional syncope directly caused by reduced forward flow.
*Autoimmune valve destruction*
- **Rheumatic fever** can cause valve damage, but this is less common in developed countries in a 67-year-old with this specific presentation.
- Autoimmune causes are usually associated with specific rheumatic diseases or serological markers, none of which are mentioned.
*Bicuspid valve*
- A **bicuspid aortic valve** is a congenital anomaly that can lead to aortic stenosis, often presenting at a younger age (40s-60s) but can manifest later due to accelerated calcification.
- While it's a possibility, in a 67-year-old without prior history, **degenerative calcification** of a trileaflet valve is statistically more likely.
Valve development US Medical PG Question 3: A 4-year-old male is brought into your office because his mother states he has been fatigued. He has not been acting like himself and has been getting tired easily while running around and playing with other children. As of last week, he has also been complaining of being short of breath. His vitals are temperature 98.6 deg F (37.2 deg C), blood pressure 100/75 mmHg, pulse 98/min, and respirations 22/min. On exam, the patient is short of breath, and there is a holosystolic murmur with an appreciable thrill along the left sternal border. There are no other noticeable abnormalities, and the mother states that the child's prenatal course along with genetic testing was normal. What is the most likely diagnosis?
- A. Atrial septal defect (ASD)
- B. Endocardial cushion defect
- C. Ventricular septal defect (VSD) (Correct Answer)
- D. Patent ductus arteriosus (PDA)
- E. Tetralogy of Fallot
Valve development Explanation: ***Ventricular septal defect (VSD)***
- A **holosystolic murmur** at the **left sternal border** with an associated **thrill** is a classic finding for a VSD.
- The patient's fatigue and shortness of breath (evidencing activity intolerance) are signs of **left-to-right shunting** causing increased pulmonary blood flow and eventual heart failure.
*Atrial septal defect (ASD)*
- An ASD typically presents with a **systolic ejection murmur** at the upper left sternal border due to increased flow across the pulmonic valve, not a holosystolic murmur.
- While it can cause fatigue and dyspnea, a thrill is less common, and the murmur quality is distinct.
*Endocardial cushion defect*
- This defect involves the atrioventricular septum, often resulting in a **split S2** and a **holosystolic murmur** best heard at the lower left sternal border.
- However, it is strongly associated with **Down syndrome**, which is ruled out by the normal genetic testing.
*Patent ductus arteriosus (PDA)*
- PDA is characterized by a **continuous "machinery" murmur** best heard below the left clavicle, which is distinct from the holosystolic murmur described.
- The associated symptoms of fatigue and dyspnea can occur, but the murmur differentiates it.
*Tetralogy of Fallot*
- This condition presents with **cyanosis** and a **crescendo-decrescendo systolic ejection murmur** at the left sternal border, not a holosystolic murmur with a thrill.
- Patients often exhibit "tet spells" and **clubbing**, which are absent in this presentation.
Valve development US Medical PG Question 4: A 3175-g (7-lb) male newborn is delivered at 39 weeks' gestation to a 29-year-old primigravid woman following a spontaneous vaginal delivery. Apgar scores are 8 and 9 at 1 and 5 minutes, respectively. Cardiac examination in the delivery room shows a continuous machine-like murmur. An echocardiogram shows a structure with blood flow between the pulmonary artery and the aorta. This structure is most likely a derivate of which of the following?
- A. 4th aortic arch
- B. 1st aortic arch
- C. 6th aortic arch (Correct Answer)
- D. 2nd aortic arch
- E. 3rd aortic arch
Valve development Explanation: ***6th aortic arch***
- The description of a "continuous machine-like murmur" and a structure with blood flow between the pulmonary artery and the aorta is characteristic of a **patent ductus arteriosus (PDA)**.
- The **ductus arteriosus** is a remnant of the **6th aortic arch**, connecting the pulmonary artery to the aorta in fetal life.
*4th aortic arch*
- The **4th aortic arch** contributes to the formation of the **aortic arch** itself on the left side and the proximal **right subclavian artery** on the right.
- Abnormalities of the 4th arch can lead to conditions like **coarctation of the aorta** or **vascular rings**, which do not typically present as a PDA.
*1st aortic arch*
- The **1st aortic arch** largely disappears, but its remnants contribute to the formation of the **maxillary artery** and the **external carotid artery**.
- It is not involved in developmental anomalies of the major vessels between the pulmonary artery and aorta.
*2nd aortic arch*
- The **2nd aortic arch** also largely regresses, but its remnants contribute to the **stapedial artery** and part of the **hyoid artery**.
- It does not play a role in the formation of the ductus arteriosus or other major arteries of the heart.
*3rd aortic arch*
- The **3rd aortic arch** develops into the common carotid arteries and the proximal internal carotid arteries.
- Genetic disorders and malformations involving this arch typically affect the carotid system, not the connection between the pulmonary artery and aorta.
Valve development US Medical PG Question 5: A 14-year-old boy who has been otherwise healthy presents to his doctor complaining of feeling easily winded and light-headed at basketball practice. He has never felt this way before and is frustrated because he is good enough to make varsity this year. He denies smoking, alcohol, or recreational drug use. His mother is very worried because her oldest son and brother had both died suddenly while playing sports despite being otherwise healthy. The transthoracic echocardiogram confirms the suspected diagnosis, which demonstrates a preserved ejection fraction and systolic anterior motion of the mitral valve. The patient is advised that he will need to stay hydrated and avoid intense exercise, and he will likely need an ICD due to his family history. Which of the following physical exam findings is consistent with this patient’s most likely diagnosis?
- A. Tricuspid regurgitation
- B. Systolic ejection murmur that radiates to the carotids
- C. S3 heart sound
- D. Mitral regurgitation
- E. Systolic ejection murmur that worsens with the Valsalva maneuver (Correct Answer)
Valve development Explanation: ***Systolic ejection murmur that worsens with the Valsalva maneuver***
- The patient's presentation with **syncope/lightheadedness during exertion**, family history of **sudden cardiac death in athletes**, and echocardiogram findings of **systolic anterior motion (SAM) of the mitral valve** are classic for **hypertrophic cardiomyopathy (HCM)**.
- The murmur of HCM is typically a **systolic ejection murmur** that **worsens with maneuvers that decrease preload**, such as the **Valsalva maneuver** or standing, because this reduction in ventricular volume exacerbates the left ventricular outflow tract (LVOT) obstruction.
*Tricuspid regurgitation*
- This is typically associated with **right heart failure** or **pulmonary hypertension**, which are not indicated by the patient's symptoms or echo findings.
- While it can be heard as a **systolic murmur**, it usually accentuates with inspiration (Carvallo's sign) and does not worsen with the Valsalva maneuver in the context of hypertrophic cardiomyopathy.
*Systolic ejection murmur that radiates to the carotids*
- A systolic ejection murmur radiating to the carotids is characteristic of **aortic stenosis**, which involves a fixed obstruction of the aortic valve.
- While both HCM and aortic stenosis cause systolic murmurs, HCM's murmur has different auscultatory behavior with preload-altering maneuvers (worsening with Valsalva) compared to aortic stenosis (which often softens or is unchanged).
*S3 heart sound*
- An **S3 heart sound** is typically a low-pitched diastolic sound associated with **volume overload** and **heart failure with reduced ejection fraction**, indicating rapid ventricular filling into a dilated ventricle.
- The patient's echocardiogram shows a **preserved ejection fraction**, and his symptoms are related to outflow obstruction, not volume overload.
*Mitral regurgitation*
- While **mitral regurgitation (MR)** can occur in HCM due to systolic anterior motion (SAM) of the mitral valve causing malcoaptation, the primary murmur heard due to the **LVOT obstruction** is a **systolic ejection murmur**.
- The murmur of MR is typically a **holosystolic murmur** that radiates to the axilla and usually **softens with the Valsalva maneuver** as reduced preload can decrease the severity of regurgitation.
Valve development US Medical PG Question 6: Shortly after delivery, a female newborn develops bluish discoloration of the lips, fingers, and toes. She was born at term to a 38-year-old primigravid woman. Pregnancy was complicated by maternal diabetes mellitus. Pulse oximetry on room air shows an oxygen saturation of 81%. Echocardiography shows immediate bifurcation of the vessel arising from the left ventricle; the vessel emerging from the right ventricle gives out coronary, head, and neck vessels. An abnormality in which of the following developmental processes most likely accounts for this patient's condition?
- A. Alignment of infundibular septum
- B. Fusion of endocardial cushion
- C. Spiraling of aorticopulmonary septum (Correct Answer)
- D. Separation of tricuspid valve tissue from myocardium
- E. Division of aorta and pulmonary artery
Valve development Explanation: ***Spiraling of aorticopulmonary septum***
- The description of a vessel arising from the left ventricle that immediately bifurcates (pulmonary artery) and a vessel from the right ventricle that gives off coronary, head, and neck vessels (aorta) is characteristic of **transposition of the great arteries (TGA)**.
- TGA results from a failure of the **aorticopulmonary septum** to spiral during embryological development, leading to the aorta originating from the right ventricle and the pulmonary artery from the left ventricle.
*Alignment of infundibular septum*
- Abnormal alignment of the infundibular septum is associated with conditions like **tetralogy of Fallot**, which involves a maligned interventricular septum and a shifted aorta, presenting with a different set of echocardiographic findings.
- While also a **cyanotic heart defect**, tetralogy of Fallot's anatomy (e.g., interventricular septal defect, pulmonary stenosis) differs from the described TGA.
*Fusion of endocardial cushion*
- Failure of fusion of the **endocardial cushions** leads to **atrioventricular septal defects**, which involve defects in both the atria and ventricular septa, and often affect the mitral and tricuspid valves.
- These defects typically present with heart failure symptoms and different echocardiographic findings than those described for TGA.
*Separation of tricuspid valve tissue from myocardium*
- An abnormality in the separation of tricuspid valve tissue from the myocardium is the cause of **Ebstein anomaly**, where the tricuspid valve leaflets are displaced downwards into the right ventricle, leading to tricuspid regurgitation.
- Ebstein anomaly is characterized by right atrial enlargement and a largely functional right ventricle, leading to issues with right heart output but not the great artery transposition described.
*Division of aorta and pulmonary artery*
- The division of the truncus arteriosus into the aorta and pulmonary artery is a normal developmental process, which when complete usually produces the correct great artery connections. However, the exact arrangement of these vessels is determined by the **spiraling of the aorticopulmonary septum**, not just the division itself.
- Failure of this division, resulting in a **persistent truncus arteriosus**, would present as a single great artery arising from both ventricles, which is distinct from the two separate but transposed vessels seen in TGA.
Valve development US Medical PG Question 7: A newborn is rushed to the neonatal ICU after becoming cyanotic shortly after birth. An ultrasound is performed which shows the aorta coming off the right ventricle and lying anterior to the pulmonary artery. The newborn is given prostaglandin E1 and surgery is planned to correct the anatomic defect. Which of the following developmental processes failed to occur in the newborn?
- A. Failure of the membranous ventricular septum to fuse with the muscular interventricular septum
- B. Failure of the septum primum to fuse with the septum secundum
- C. Failure of the aorticopulmonary septum to spiral (Correct Answer)
- D. Failure of the ductus venosus to close
- E. Failure of the ductus arteriosus to close
Valve development Explanation: ***Failure of the aorticopulmonary septum to spiral***
- **Transposition of the great arteries (TGA)**, characterized by the aorta originating from the right ventricle and the pulmonary artery from the left ventricle, results from the **aorticopulmonary septum** failing to spiral properly during embryological development.
- This defect leads to two separate circulatory systems, causing severe **cyanosis** shortly after birth and requiring **prostaglandin E1** to maintain a patent ductus arteriosus for mixing of oxygenated and deoxygenated blood.
- This is a ductal-dependent lesion requiring urgent intervention.
*Failure of the membranous ventricular septum to fuse with the muscular interventricular septum*
- This specific failure leads to a **ventricular septal defect (VSD)**, which allows blood to shunt between ventricles.
- While VSDs can cause cyanosis if large and associated with pulmonary hypertension (Eisenmenger syndrome), the description of **great artery transposition** is not caused by this developmental failure.
*Failure of the septum primum to fuse with the septum secundum*
- This developmental anomaly results in a **patent foramen ovale (PFO)** or an **atrial septal defect (ASD)**.
- These defects typically cause a left-to-right shunt and present with symptoms later in life, not with severe immediate cyanosis.
- In TGA, an ASD may actually be beneficial as it allows some mixing of blood.
*Failure of the ductus venosus to close*
- The **ductus venosus** shunts oxygenated blood from the umbilical vein directly to the inferior vena cava, bypassing the fetal liver during intrauterine life.
- Persistent patency of the ductus venosus after birth is rare and does not cause the severe cyanosis and specific great artery anatomy seen in TGA.
*Failure of the ductus arteriosus to close*
- A **patent ductus arteriosus (PDA)** allows blood to flow from the aorta to the pulmonary artery after birth, which can lead to pulmonary overcirculation.
- In **transposition of the great arteries**, a PDA is actually crucial for survival as it provides a pathway for mixing of oxygenated and deoxygenated blood; maintaining PDA patency with PGE1 is the initial management, not a cause of the condition.
Valve development US Medical PG Question 8: A 26-year-old woman comes to the physician because she has not had a menstrual period for 5 weeks. Menarche was at the age of 14 years and menses occurred at regular 30-day intervals. She reports having unprotected sexual intercourse 3 weeks ago. A urine pregnancy test is positive. Which of the following best describes the stage of development of the embryo at this time?
- A. Fetal heart is beating, but cardiac activity is not yet visible on ultrasound
- B. Limb buds have formed, but fetal movements have not begun
- C. Sexual differentiation has begun, but fetal movement has not started
- D. Neural crest has formed, but limb buds have not yet formed (Correct Answer)
- E. Implantation has occurred, but notochord has not yet formed
Valve development Explanation: ***Neural crest has formed, but limb buds have not yet formed***
- At **5 weeks gestational age (3 weeks post-fertilization)**, neurulation is completing or recently completed
- **Neural crest cells** migrate from the neural folds during weeks 3-4 post-fertilization and are definitely present by this time
- **Limb buds** appear later, around week 4-5 post-fertilization (week 6-7 gestational age), making this the most accurate description for the current developmental stage
*Fetal heart is beating, but cardiac activity is not yet visible on ultrasound*
- The primitive heart tube begins contracting around day 22-23 post-fertilization (early week 4)
- At 3 weeks post-fertilization (5 weeks gestational age), the heart may just be starting to beat, but this timing is less precise
- Cardiac activity becomes visible on transvaginal ultrasound around 5.5-6 weeks gestational age, so this option is close but less precise than the correct answer
*Limb buds have formed, but fetal movements have not begun*
- **Limb buds** typically appear around week 4-5 post-fertilization (week 6-7 gestational age)
- This is **too advanced** for 3 weeks post-fertilization
- While fetal movements aren't perceptible to the mother until 16-20 weeks, they begin much later than the current stage
*Sexual differentiation has begun, but fetal movement has not started*
- **Sexual differentiation** of the gonads begins around week 7 post-fertilization (week 9 gestational age)
- External genitalia differentiation occurs even later (weeks 9-12 post-fertilization)
- This stage is **far too advanced** for the current 3-week post-fertilization timeframe
*Implantation has occurred, but notochord has not yet formed*
- **Implantation** occurs 6-12 days after fertilization, which is approximately 2-3 weeks before a positive pregnancy test
- The **notochord** forms during gastrulation in the **3rd week post-fertilization** (5th week gestational age)
- By the time of this positive pregnancy test (5 weeks gestational age), the notochord has **already formed**, making this statement incorrect
Valve development US Medical PG Question 9: A 55-year-old man visits the clinic with his wife. He has had difficulty swallowing solid foods for the past 2 months. His wife adds that his voice is getting hoarse but they thought it was due to his recent flu. His medical history is significant for type 2 diabetes mellitus for which he is on metformin. He suffered from many childhood diseases due to lack of medical care and poverty. His blood pressure is 125/87 mm Hg, pulse 95/min, respiratory rate 14/min, and temperature 37.1°C (98.7°F). On examination, an opening snap is heard over the cardiac apex. An echocardiogram shows an enlarged cardiac chamber pressing into his esophagus. Changes in which of the following structures is most likely responsible for this patient’s symptoms?
- A. Patent ductus arteriosus
- B. Right ventricle
- C. Left ventricle
- D. Left atrium (Correct Answer)
- E. Right atrium
Valve development Explanation: ***Left atrium***
- The patient's symptoms of **dysphagia (difficulty swallowing)** and **hoarseness** suggest compression of anatomical structures by an enlarged cardiac chamber, which the echocardiogram confirms.
- An enlarged **left atrium**, typically due to **mitral stenosis**, can compress the esophagus (leading to dysphagia) and the **recurrent laryngeal nerve** (leading to hoarseness, known as Ortner's syndrome). The **opening snap** at the apex is also highly characteristic of mitral stenosis.
*Patent ductus arteriosus*
- A **patent ductus arteriosus (PDA)** is a congenital heart defect that typically causes a **continuous murmur** and may lead to pulmonary hypertension or heart failure, but not direct compression of the esophagus or recurrent laryngeal nerve.
- The symptoms of PDA are usually present earlier in life, though uncorrected large PDAs can cause symptoms in adulthood, they do not cause dysphagia or hoarseness through direct esophageal compression.
*Right ventricle*
- An enlarged **right ventricle** usually causes symptoms related to right heart failure like **peripheral edema** or **dyspnea** due to pulmonary hypertension.
- It is not anatomically positioned to compress the esophagus or recurrent laryngeal nerve in a way that would cause dysphagia or hoarseness.
*Left ventricle*
- An enlarged **left ventricle** (e.g., due to hypertension or aortic stenosis) primarily causes symptoms like **dyspnea on exertion** or **angina**.
- While a severely dilated left ventricle can displace other structures, it does not typically cause direct esophageal compression leading to dysphagia or recurrent laryngeal nerve compression leading to hoarseness.
*Right atrium*
- An enlarged **right atrium** might be seen in conditions like tricuspid regurgitation or right heart failure but can manifest as **edema** or **jugular venous distention**.
- It is not anatomically positioned to cause dysphagia or hoarseness from esophageal or recurrent laryngeal nerve compression.
Valve development US Medical PG Question 10: A 28-year-old woman with corrected transposition of the great arteries (L-TGA) who has been asymptomatic presents for preconception counseling. She has a systemic right ventricle supporting systemic circulation and asks about pregnancy risks. Her cardiologist notes mild tricuspid regurgitation. Evaluate the embryologic basis of her condition and synthesize recommendations regarding pregnancy.
- A. Simple transposition with late correction; pregnancy is safe with standard monitoring
- B. Both AV and ventriculoarterial discordance creating physiologically corrected circulation; pregnancy acceptable if systemic RV function normal, but requires high-risk obstetric and cardiology co-management (Correct Answer)
- C. Uncorrected transposition incompatible with pregnancy; recommend adoption
- D. Iatrogenic correction; pregnancy safe as anatomy is normalized
- E. Partial transposition; standard prenatal care is sufficient
Valve development Explanation: ***Both AV and ventriculoarterial discordance creating physiologically corrected circulation; pregnancy acceptable if systemic RV function normal, but requires high-risk obstetric and cardiology co-management***
- **L-TGA** involves **levo-looping** of the heart tube where the **morphologic right ventricle** (RV) supports the systemic circulation due to double discordance (atrioventricular and ventriculoarterial).
- Pregnancy is generally tolerated (maternal WHO class III) if **systemic RV function** is preserved, but requires multidisciplinary care to monitor for **heart failure**, **arrhythmias**, and worsening **tricuspid regurgitation**.
*Simple transposition with late correction; pregnancy is safe with standard monitoring*
- **D-TGA** (simple transposition) requires surgical correction (e.g., Arterial Switch) and has a distinct embryology involving failure of **conotruncal septation** spiral.
- Unlike L-TGA, corrected D-TGA carries different risks and would not be classified as having a "systemic right ventricle" if an **arterial switch** was performed.
*Uncorrected transposition incompatible with pregnancy; recommend adoption*
- **L-TGA** is "congenitally corrected," meaning blood flows in the correct physiological sequence; it is not inherently incompatible with pregnancy if the **systemic RV** is functional.
- Maternal mortality is not high enough to warrant absolute contraindication unless there is severe **RV dysfunction** or NYHA Class III/IV symptoms.
*Iatrogenic correction; pregnancy safe as anatomy is normalized*
- This condition is **congenitally corrected**, meaning the "correction" occurred during **embryogenesis** due to the double mismatch, not through surgery.
- The anatomy is never truly "normalized" because the **tricuspid valve** and **RV** are not designed for high-pressure systemic resistance, making pregnancy a high-risk event.
*Partial transposition; standard prenatal care is sufficient*
- There is no clinical entity termed "partial transposition" in this context; L-TGA is a complete, albeit **physiologically corrected**, malformation.
- Standard prenatal care is insufficient because the hemodynamic stress of pregnancy can trigger **systemic RV failure** or significant **heart block**.
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