Correct answer is C:
This young lady’s presentation is consistent with Cardioneurogenic syncope. Patient is most vulnerable when dehydrated, such as early in the morning. Syncope may be preceded by sense of nausea or disorientation, followed by fainting. Beta blockers are used to prevent the hypercontractility from occurring, thus breaking the cycle even before bradycardia occurs. Severe hypertension may cause reflex bradycardia, but this does not appear to be the case here. Bradycardia associated with hypertension is not associated with syncope.

Correct answer is C:
The heart size is within normal limits and the cardiac silhouette is normal.

Correct answer is B:

This patient has tetralogy of Fallot with pulmonary atresia and collaterals from subclavian arteries to pulmonary circulation resulting in an abnormal shadow, above that of the heart. Pericardial effusion enlarges the heart and pleural effusion surrounds the lung fields, neither of these conditions would cause a mass like effect in the right upper chest.

Correct answer is B:
The child in the case scenario “A” has typical stigmata of Down syndrome. 40% of these children are known to have congenital heart disease, mostly complete atrio-ventricular canal (AVC) defect. However, this child appears to have peripheral pulmonary stenosis, a normal finding in children less than 6 weeks of age. The murmur of AVC defect is that of a VSD, i.e. holosystolic and harsh.
The child in case scenario “B” has the features of Holt-Oram syndrome. This anomaly affects skeletal and cardiovascular systems. Patients have hypoplasia of lateral arm skeletal structures as well cardiac anomalies. The most encountered heart lesion is atrial septal defect, which appears to be the case here. The murmur is secondary to increase pulmonary valve blood flow and the fixed splitting of the second heart sound is due to constant increase in blood flow due to the ASD.
The patient in case scenario “C” is pregnant. Here fetus has congenital heart disease, but there is no clinical evidence that the mother has any cardiac problem. The murmur heard in this patient is a “mammary soufflé” which is heard in women with enlarging breast, as encountered in teenagers and pregnancy.
The child in case scenario “D” most probably has reactive airway disease. The bronchodilators used causes tachycardia and occasionally premature atrial contractions, this may explain the irregularity of the heart rhythm. The murmur described here is consistent with a venous hum since it is supra-clavicular not sub-clavicular which would make one think of PDA. The murmur increases in intensity in upright position because of increase venous return through the jugular veins when standing, this murmur should disappear if pressure is applied to that side of the neck.

Correct answer is A.
Modified in my version to be B (based on the scenario)
Normal heart sounds, no murmur.

Correct answer is B
There is a systolic ejection murmur with fixed splitting of second heart sound a soft mid-diastolic murmur. The patient appears to have Holt-Oram syndrome.

Correct answer is C
Diagnosis is pulmonary stenosis. Same answer, changed scenario

Correct answer is A
Diagnosis is patent ductus arteriosus. Same answer, changed scenario

Correct answer is A
The murmur is ejection systolic murmur with normal first and second heart sounds. Same answer, changed scenario

Correct answer is B
Ebstein’s malformation may have a variety of murmurs, here there is fixed splitting of second heart sound. Same answer, changed scenario

Correct answer is C
The murmur is diastolic; this would be heard loudest at the apical region. Same answer, changed scenario

Correct answer is A
The murmur (systolic click followed by a murmur) is of mitral valve prolapse, known to be associated with chest pain. Same answer, changed scenario

Correct answer is D
The murmur is holosystolic. The defect appears to be smaller now, thus lack of symptoms. Same answer, changed scenario

Correct answer is D
This patient has aortic regurgitation as complication to ventricular septal defect. I modified the scenario and the choices. Correct answer is still D.

Correct answer is B
The murmur is that of an atrial septal defect. Same answer, changed scenario

Correct answer is A
The murmur is a soft systolic murmur, suggestive of Still’s (aortic flow innocent murmur). Peripheral pulmonary stenosis is not normal at this age. Same answer, changed scenario

Correct answer is B
The murmur is holosystolic; this would most probably be loudest at the apex. Same answer, changed scenario

xxCorrect answer is A:
The CXR shows biventricular enlargement, increase pulmonary blood flow and haziness of the right lung field, which may suggest right pleural effusion. In aortic stenosis the LV is enlarged, causing the apex to be downwards towards the diaphragm as well as leftward displacement. Pulmonary stenosis causes right ventricular hypertrophy causing the left ventricular apex to be uplifted, which is noted here, however, the cardiac silhouette is typically not enlarged in the antero-posterior projection. Pulmonary vascular markings are normal in both aortic and pulmonary stenosis. Atrial septal defect does not cause left ventricular enlargement.

Correct answer is D:

The cardiac apex is to the left, the enlarged right border of the heart is due to dilated right atrium due to increased blood flow secondary to atrial septal defect. Ventricular inversion is characterized by apex towards the left as usual, however, the mediastinum is narrow due to abnormal relationship of the great vessels to each other.

Correct answer is A:

The stomach bubble in this patient is leftwards, which is normal. The atrial situs usually follows the abdominal situs, therefore, there is most probably situs solitus. None of the other pathologies are present in this CXR.

Correct answer is D:

Enlarged cardiac silhouette with downwards pointing apex indicates left ventricular hypertrophy. Right ventricular hypertrophy causes upwards lifting of the cardiac apex without enlarging cardiac silhouette in antero-posterior projections of CXR. Right atrial enlargement causes bulging of right heart border, while left atrial enlargement causes widening of carina angle, double left atrial shadow or posterior deviation of esophagus on a lateral projection.

Correct answer is C:

The catheter is placed through internal jugular access and courses through the innominant vein to end in the superior vena cava.

Correct answer is B:
The mediastinum is narrow, which suggests abnormal relationship of the great vessels to each other, this is also seen in atresia of either one of the great vessels.

Correct answer is C:

The left ventricle is dilated with slightly prominent pulmonary vascular markings. This patient has rheumatic heart disease with aortic and mitral regurgitation.

Correct answer is A:

The pulmonary vascular markings are significantly reduced in this patient with Alagille syndrome with severe peripheral pulmonary stenosis.

Correct answer is D:
Pectus excavatum causes the heart to deviate leftwards and clockwise (looking at the heart from the apex) This will cause no hemodynamic effect, however, the change in location of the various cardiac chambers to the fixed position of limb and chest leads will cause the changes in the ECG, this includes the following:
• Negative P wave in V1, because the right atrium becomes more anterior than rightwards.
• RSR’ in V1 as seen with RVH … due to a more anterior position of the RVOT
• QR waves in anterior chest leads … due to a more anterior position of the RV and change of ventricular septal plane.
• Right axis deviation … due to clockwise rotation of the heart.

The chest pain described here is typical of costo-chondritis and is not related to the ECG changes.

Correct answer is C:

The first ECG shows left atrial enlargement (LAE) and left ventricular hypertrophy (LVH). Note that the standardization mark indicates half standard in the chest leads, which means that the R waves in V6 are twice as tall as shown in the ECG. The criterion for LAE is wide and bifid P waves, while LVH is determined by tall R waves in V6 and deep S waves in V1.

The second ECG shows pure R wave in V1 which is indicates right ventricular hypertrophy (RVH); signs of LVH seem to resolve in the second ECG. Therefore, this lesion initially caused LAE and LVH and after several years, LAE and LVH resolved to be replaced by RVH.

Pulmonary stenosis causes RVH and does not impact the left ventricle.

Aortic stenosis on the other hand may cause LVH and even LAE, with prolonged course and severe condition it may lead to pulmonary venous hypertension followed by RVH, however, LVH and LAE should not have resolved.

Patent ductus arteriosus (PDA) causes left to right shunting at the arterial level, resulting in increase pulmonary blood flow and subsequently increase in pulmonary venous return which would cause volume burden on the LA and LV, resulting in the LAE and LVH pattern of the ECG. Years later, the excessive blood flow in the pulmonary circulation will cause pulmonary vascular obstructive disease which would cause less blood flow to the lungs, thus resolution of LAE and LVH and increasing RVH due to developing pulmonary hypertension.

Tetralogy of Fallot causes RVH and does not affect the left heart.

Correct answer is D:

The rhythm in this ECG is that of atrial flutter. The child is table hemodynamically; therefore, there is no need for cardioversion. Intravenous adenosine push is effective in Supraventricular tachycardia and would not interrupt atrial flutter. Amiodarone is effective in many arrhythmias, atrial flutter included, however, it is not the first line of therapy since it has many side effects such as hypothyroidism and pulmonary fibrosis.

Correct answer is C:

There are no p waves in this ECG; therefore, the rhythm is of Junctional origin. The determining factor for differentiating between the first three rhythms is the heart rate. Junctional ectopic tachycardia is a rapid heart rate, noted post0operatively leading to hemodynamic compromise. Accelerated Junctional rhythm is slower and does not cause hemodynamic compromise. The faster Junctional rhythm in the latter two causes the sinus node to be dormant. Escape Junctional rhythm is slow. It occurs with abnormality of the sinus node, resulting in an escape rhythm.

Correct answer is D:

Flutter waves are best seen in leads III and aVF. AV conduction is blocked 2:1

Correct answer is B:

The QRS complexes are narrow, indicating a Supraventricular rhythm.  No p waves are seen prior to QRS complexes, suggestive of Junctional rhythm.

Correct answer is A:

The QRS complexes are wide with RsR pattern in left chest leads (V6), indicative of left bundle branch block.

Correct answer is B:

There is increase in the left ventricular forces (tall R in V6 and deep S in V1) which are indicative of left ventricular hypertrophy, as seen in aortic stenosis.  Pulmonary stenosis, tetralogy of Fallot and atrial septal defect all cause right ventricular hypertrophy.  Patients with atrial septal defect also have right atrial enlargement.

Correct answer is A:

Options B, C and D are correct if they where isolated findings, however, seeing all these abnormalities on ECG suggest that the lead connections are wrong (connecting right leads to left extremities and left leads to right extremities). With this lead connection, the p and QRS axis become abnormal (this ECG suggest low left atrial axis which is very unusual). In addition q waves are seen in leads which should not have any q waves such leads I and aVL.

Correct answer is C:

The ECG is normal; option C suggests an innocent heart murmur.  Option A suggests a ventricular septal defect which would likely have LVH and possibly RVH.  Option B suggests mitral stenosis, which would have left atrial enlargement.  Option D suggests pulmonary hypertension which would be associated with right ventricular hypertrophy.

Correct answer is C:

The rhythm is sinus with occasional wide QRS complexes not proceeded by a p wave indicating premature ventricular contraction.

Correct answer is B:

The giant P waves suggest Ebstein’s malformation.

Correct answer is B:

Murmur in case scenario (A) is consistent with ventricular septal defect, the holosystolic murmur is caused by left to right shunting at the defect, while the mid-diastolic murmur is due to increase flow across the mitral valve.

Murmur in scenario (B) is typical of an atrial septal defect.  The systolic murmur is due to increase blood flow across the pulmonary valve, while the diastolic murmur is due to increase flow across the tricuspid valve.  Fixed splitting of S2 is due to constant delay of pulmonary valve closure due to increase flow across the pulmonary valve due to left to right shunting at the atrial septal defect.

Murmur in scenario (C) is consistent with a patent ductus arteriosus.  The cause of the clicking noise is not clear, but observed in these patients, thus the description “machinery murmur”.

Murmur in scenario (D) is consistent with mitral valve prolapse.

Correct answer is C:

The QRS complexes are wide with RsR pattern in right chest leads (V1), indicative of right bundle branch block.

Correct answer is D:

qr pattern of QRS complex in the right chest lead is indicative of any of the above mentioned causes, it is also found in pectus excavatum.  RVH is most likely in this ECG in view of normal QRS axis (80 degrees).  All other cases would most probably have abnormal QRS axis.

Correct answer is A:

The rhythm is sinus (normal axis p waves preceding each QRS complex).  The p wave rate changes with respiration, thus consistent with sinus arrhythmia.  In Wenckebach the PR interval becomes progressively longer, then a p wave does not conduct.

Correct answer is A:

The heart rate (60 bpm) is too slow for a 6 month old.  This is sinus bradycardia.

Correct answer is B:

The child should be cardioverted if hemodynamically unstable, which is not the case in this example.  Amiodarone orally requires several days to be effective.  Vagal stimulation could be attempted here, but not through pressure over eyeballs, which is contraindicated in young children as damage to the eyeball may result.

Correct answer is C:

The rhythm in this ECG shows wide QRS complex tachycardia.  Treatment in this case should be initially fashioned as if the abnormal rhythm is ventricular tachycardia.  However, in the presence of known bundle branch block with similar pattern QRS as before the arrhythmia, then the rapid heart rate in this case may be secondary to Supraventricular tachycardia and treatment with adenosine could be considered.

Correct answer is A:

This ECG demonstrates short pr interval with delta waves (causing wide QRS) in inferior and lateral chest leads.  These findings are consistent with Wolf-Parkinson-White syndrome.

Correct answer is D

Echocardiography is safe to use in children. It utilizes ultrasound waves, which are harmless to human tissue. Continuous wave Doppler may cause increase in body temperature when used for prolonged periods in premature infants with small body mass. Ultrasound waves are not known to interfere with wound healing. The only precaution needed in the post-operative period is the use of sterile technique so as not to cause wound infection.

Correct answer is C:

Cardiac catheterization is performed for 2 reasons: 1) Obtain diagnostic data such as pressures and magnitude of shunt lesions, or 2) Provide therapeutic measures such as close defects or reduce pressure gradients of stenotic valves and vessels.

A small mid-muscular VSD is hemodynamically insignificant and does not pose threat to cardiac valves as some outflow ventricular septal defects do. Therefore closure with a device, such as the Amplatz device is not necessary.

A large secundum atrial septal defect is hemodynamically significant and will not close spontaneously; therefore, closure in the catheterization laboratory is indicated.

Patent ductus arteriosus should be closed at all ages outside the neonatal period since it poses high bacterial endocarditis risk. Most cardiologists advocate observation only of small patent ductus arteriosus not associated with a murmur (silent), since the risk of bacterial endocarditis is negligible in such lesions.

Correct answer is C:

Secundum atrial septal defect can be closed by occlusion devices as long as there is a reasonable rim of atrial septal tissue surrounding the defect to enable anchoring of device.

Apical ventricular septal defects are difficult to close surgically sine the area is not easily accessible to the surgeon without a left ventriculotomy which may leave the left ventricle scarred.

Sinus venosus atrial septal defects lack a rim of tissue adjacent to the superior and/or inferior vena cava and such are not amenable to device closure in the catheterization laboratory.

Pulmonary stenosis in patients with atrial septal defects restrict blood flow to the lungs and thus prevent significant congestive heart failure, however the combination of these two lesions result in right ventricular volume and pressure overload. Both lesions can be treated in the catheterization laboratory in one setting.

Correct answer is B:

The clinical picture is consistent with pericardial effusion and pending tamponade. This may be a result of trauma to cardiovascular walls during catheterization by catheters or the occlusion device. A large residual atrial septal defect will not cause any more congestive heart failure than before device closure, therefore unlikely to cause this picture of poor cardiac output.

Cardiac arrhythmia may occur during the catheterization procedure and occasionally persists thereafter; however, this will not lead to large cardiac silhouette or muffled cardiac tones.

Allergic reaction may manifest after contrast injection such as skin manifestation, upper airway obstruction, etc. This patient did not present with these manifestations.

Correct answer is A:

Complete surgical repair in all patients with Tetralogy of Fallot should be considered when the child is 6 months of age since the morbidity and mortality of complete surgical repair plateaus after 6 months of age. Complete repair should not be delayed, if possible, beyond 1 year of age as the risk of brain abscess or embolization due to right to left shunting at the ventricular septal defect increases after the first year of age. A systemic to pulmonary arterial shunt is used only when complete surgical repair is not possible due to small pulmonary branches or unstable patients. Complete surgical repair entails closure of ventricular septal defect with a patch, enlarging the right ventricular outflow through muscle resection and patch placement. Pulmonary valve annulus is best left without patch placement if near normal in size, however if small it could be enlarged with a patch. Patch enlargement of the pulmonary valve annulus will eliminate pulmonary valve stenosis, but at the expense of significant pulmonary regurgitation which will eventually lead to right ventricular dilation and dysfunction and arrhythmias. Down syndrome has no impact on timing of surgery as it does not reduce or increase operative risks.

Correct answer is D:

Only secundum atrial septal defect could be closed by device as it requires atrial septal wall surrounding the defect which is not present in primum and sinus venosus type atrial septal defects. Pulmonary valve stenosis could be treated in the catheterization laboratory by balloon dilation at the same time an atrial septal defect device is deployed.

Correct answer is D:

A child with tricuspid atresia is dependent upon the patent ductus arteriosus for pulmonary blood flow. Therefore, prostaglandin infusion is important soon after diagnosis. Once the child is stable, 1-2 weeks of age, a systemic to pulmonary arterial shunt will provide a reliable source of pulmonary blood flow without the disadvantages of prostaglandin infusion. A Glenn shunt connects the superior vena cava directly to the right pulmonary artery; this cannot be done prior 6-9 months of age since the normally elevated pulmonary vascular resistance does not allow proper function of a Glenn shunt which requires low pulmonary vascular resistance for proper functioning. A Glenn shunt should maintain the oxygen saturation at about 80% till the child is about 18-24 months of age, at which time a Fontan procedure could be performed. Fontan procedure entails connecting the inferior vena cava to the pulmonary arteries through a tunnel within the right atrium or an extra-cardiac conduit. The Fontan procedure allows all systemic venous return (except that from the coronary sinus) to flow directly to the pulmonary circulation, bypassing the cardiac chambers.

Correct answer is A:

When all pulmonary veins drain in an anomalous fashion to the superior vena cava, the connecting veins are typical small and may become stenosed resulting in severe obstruction. Therefore, such children are repaired immediately. Large apical ventricular septal defect may cause congestive heart failure which does not respond to medications, however, this typically occurs at few weeks of age. Large apical ventricular septal defect could be closed by a device in the cardiac catheterization laboratory or palliated by placing a band on the pulmonary artery to restrict blood flow.

Double outlet right ventricle and transposition of the great vessels with large atrial and ventricular septal defects are stable lesions which result in mild to moderate oxygen desaturation, thus allowing the child to grow for few weeks to months prior to the need to surgically intervene.

Correct answer is B:

Pulmonary edema is the result of large pulmonary blood flow secondary to left to right shunting at the ventricular septal defect. Surgical repair will cure this.

Sepsis or recent RSV pneumonitis are contraindications to surgery since the immune system is depressed secondary to surgical intervention due to the cardio-pulmonary by-pass machine. Cardiac surgery requires heparinaztion which will be deleterious to a child with cerebral hemorrhage.

Correct answer is B:

This drop in the urine output in this child is most probably secondary to excessive diuresis over the past 2 days due to aggressive furosemide dosing. This is supported by a low central venous pressure and elevated BUN. It is not necessary to add new pharmacologic agents or infuse with fluid. Withholding furosemide or adjusting to a lower dose will most probably correct the anomaly.

Correct answer is C:

Perimembranous VSD tend to close by incorporation of tricuspid valve tissue.  This forms an aneurysmal pouch at its orifice, which is likely to eventually completely close the VSD defect.

Option A is incorrect since large muscular VSDs, including those in the apex are not likely to spontaneously close.

Option B is incorrect since outflow tract VSDs are less likely to spontaneously close than perimembranous or muscular VSDs.

Option D is incorrect since inlet VSD with or without AVCD does not close spontaneously.

Correct answer is B:

PDA is known to pose a higher risk of sub-acute bacterial endocarditis than other lesions, possibly due to the high terbulent flow.  All PDAs should be closed.  Attempts to close in the cardiac catheterization laboratory should be attempted first, if not possible, then surgical closure is recommended.

Congestive heart failure in patients with PDA is related to the amount of blood flow shunted across.  Small defects should cause limited increase in pulmonary blood flow and consequently not cause congestive heart failure.

Pulmonary vascular obstructive disease is not expected as a complication to a small PDA due to limited increase in pulmonary blood flow with no significant impact on pulmonary vasculature.

Paradoxical embolization is known to occur with small atrial septal defects or even patent foramen ovale, but not with PDA.

Correct answer is C:

This child with complete atrioventricular canal defect has evidence of large shunting (at atrial and ventricular levels) causing increase pulmonary blood flow and congestive heart failure. Patients with complete atrioventricular canal defects may have large atrial and ventricular level defects allowing for some mixing of blood and mild desaturation as in this case. Oxygen desaturation due to high pulmonary vascular resistance is unlikely at 6 months of age, particularly in a patient without Down syndrome. Furthermore, elevated pulmonary vascular resistance resulting in pulmonary hypertension will have reduced pulmonary blood flow, not increased as it is clear in this case. Pulmonary stenosis, or tetralogy of Fallot when combined with complete atrioventricular canal defect present with cyanosis, but again these patients do not have evidence of increased pulmonary blood flow.

Correct answer is A:

In truncus arteriosus the pulmonary arteries are connected directly to the truncus (ascending aorta). The right and left pulmonary arteries may be connected together, through a short main pulmonary artery, or separately. Either way, there is no pulmonary valve. The hallmark of truncus arteriosus is presence of a single semilunar valve. Since the pulmonary arteries are directly connected to the truncus, a ductus arteriosus becomes unnecessary, though sometimes present. The pulmonary arteries tend to be small; however, the direct communication to the aorta results in high pulmonary blood flow and good oxygen saturation as well as resulting in pulmonary edema and congestive heart failure. The high pulmonary blood flow and risk of early pulmonary vascular resistance may result in pulmonary vascular obstructive disease, thus necessitating early surgical repair.

Correct answer is B:

The left coronary artery tends to be the dominant coronary artery. Coursing between the two great vessels due to an anomalous origin is likely to cause sudden death. On the other hand, anomalous origin of the right coronary artery is not known to cause sudden death. Both idiopathic hypertrophic sub-aortic stenosis and prolonged QT syndrome may cause sudden death, the former due to sudden obstruction of an already small left ventricular outflow tract and the latter due to the potential to develop ventricular tachycardia (torsades de pointis).

Correct Answer is A

A normal shortening fraction of the left ventricle is 28-35%. �A child with cardiogenic shock, as in this case, will have lower shortening fraction.

Correct answer is D

2-D echocardiography show cardiac structures well. �Central venous catheters and vegetations are well demonstrated by 2-D echocardiography. �Color Doppler is used to demonstrate blood flow, while Doppler echocardiography demonstrates pressure gradients across cardiac structures. �Chest radiography shows catheters well, but not capable of demonstrating soft tissue such as vegetations within the cardiac silhouette.

Correct answer is C

Ultrasound waves are reflected when it passes from soft tissue to air and as such it cannot penetrate Pneumopericardium. �Accumulation of fluid in the pleura or pericardium does not cause significant ultrasound waves reflection and are very well visualized by echocardiography. �Mediastinitis does not significantly alter ultrasound waves, and as such does not interfere with cardiac imaging.

Correct answer is B

Echocardiography is not a sensitive tool in the assessment of chest pain. �However, it can demonstrate one of the rare causes of chest pain: Anomalous left coronary artery from right coronary sinus. �In this abnormality, the left coronary artery emerges in an anomalous fashion from the right coronary sinus, thus coursing between the aorta and pulmonary arterial trunk. �With exercise, this coronary artery may be compressed causing myocardial ischemia or even sudden death.

Correct answer is A:

Cardiac valves and structures are seen well with echocardiography since it shows soft tissue well. �On the other hand peripheral pulmonary vascular tree is within lung tissues which act as a barrier to ultrasound waves.

Correct answer is A:

Atrial septal defect shunt is best measured by comparing the oxygen saturation of the mixed venous blood and that of the aorta. When blood shunts left to right at the atrial septal defect it causes the oxygen saturation in the right atrium to rise, however, thorough mixing of blood does not occur in the right atrium but more distally in the right heart circulation, such as in the pulmonary arteries. The higher the oxygen saturation in the pulmonary artery as compared to that of the aorta, the more blood volume shunted left to right at the atrial level.

Correct answer is C:

Elevated central venous pressure and evidence of depressed cardiac output (low blood pressure and narrow pulse pressure as well as prolonged capillary refill) suggest cardiac tamponade secondary to significant pericardial effusion.

Severe aortic regurgitation will cause wide pulse pressure due to drop in diastolic pressure. Pleural effusion will interfere with oxidation and less likely with cardiac output. Dilated cardiac chambers alone cannot explain the elevated central venous pressure and depressed cardiac output.

Correct answer is D:

Despite being clear, the pleural effusion in this child is chyle. The high lymphocyte count is suggestive of the chyle nature of this effusion. The white milky appearance of chyle is due to its high fat contents. This is not present in children who are not feeding orally, rendering the color of effusion clear. Chylothorax is seen in patients with Fontan procedure due to elevation of the central venous pressure which interferes with proper drainage of lymphatic fluid from the gastro-intestinal tract. Reducing the rate of effusion in such patients is done through reduction of volume of chyle through eliminating oral food intake and providing nutrition through total intravenous hyperalimentaion or using diet with medium chain triglycerides.

Correct answer is A:

In unprepared cyanotic congenital heart diseases, oxygen saturation depends upon the extent of pulmonary blood flow. �The greater the pulmonary blood flow, the higher the oxygen saturation. �Therefore, almost normal oxygen saturation could be achieved in infants if the pulmonary blood flow is allowed to be very high. �This is detrimental, since the high pulmonary blood flow will result in pulmonary edema and volume overload of the cardiac chambers resulting in congestive heart failure. �Therefore it is always best to aim for an oxygen saturation that does not burden the heart excessively, yet is appropriate for normal growth, such as an oxygen saturation of 75-85%.

The last set of parameters is not ideal since the high heart rate and the low blood pressure may reflect low systemic vascular resistance, which if corrected may lead to elevation of pulmonary blood flow and oxygen saturation.

Correct answer is A:

The coronary sinus, which drains the myocardium venous circulation, opens into the systemic atrium, thus joining the pulmonary venous blood and causing the oxygen saturation in the single ventricle and out into the systemic circulation to slightly drop. This is why patients with Fontan procedure have somewhat low oxygen saturation (92-95%), even without a Fontan circuit fenestration.

Correct answer is C:
The rhythm is that of Junctional ectopic tachycardia (JET), a known complication after surgical repair of Tetralogy of Fallot due to irritation of the atrio-ventricular nodal region. These arrhythmias are malignant since the heart rate is rapid; there is loss of coordination between atrial and ventricular contractions and the compromised myocardium due to surgical repair. Furthermore, these arrhythmias are difficult to treat. In many instances they appear to be precipitated by a rise in the temperature and could be treated or slowed down by lowering the temperature, even to sub normal levels. The only medication which may be helpful is amiodarone intravenously.

Correct answer is A:

Murmurs in atrial septal defect are not related to blood flow across the septal defect.  The pressure difference between the left and right atria is too small to generate turbulent blood flow, which could be heard as a murmur.  Instead, the increase in right heart blood flow will cause turbulent flow across the pulmonary valve leading to the systolic flow murmur.  The excessive blood flow across the pulmonic valve will cause it to always close late, resulting in fixed splitting of the second heart sound.  If the ASD is large enough it will cause the flow through the right heart to be increased even more causing turbulent flow across the tricuspid valve as well, exhibited in auscultation as a mid-diastolic murmur.  Tricuspid blood flow tends to be less turbulent even with increase blood flow through the right heart since it is larger in diameter than the pulmonic valve, but with larger ASD, it will eventually be turbulent enough to cause a heart murmur as well.

Option B is incorrect since pulmonary regurgitation murmur though diastolic, is in early diastole and not mid diastolic.  Furthermore, pulmonary regurgitation, due to small pressure differences between the pulmonary artery and the right ventricle during diastole tends to be inaudible.

Option C is incorrect since the size of the ASD does not curtail its closure through cardiac catheterization at this age.  Devices are available to close even the very large defects in this age group.  It should be noted that at 2 years of age, closure is postponed till about 5 years of age unless there is significant heart failure, not responding to medications.

Option D is incorrect since the type of ASD has no impact on the murmur produced.  All types of ASD will produce similar murmurs.

Correct answer is B:

Two factors help determine the possibility of spontaneous closure of an ASD.  First is type, secundum ASD is the only type amenable to spontaneous closure.  Primum and sinus venosus ASD defects are not likely to close spontaneously.  The second factor is the size of ASD.  Small secundum ASD (smaller than 3 mm) are very likely to close spontaneously, whereas secundum ASD larger than 8 mm are unlikely to close.

Option A is incorrect since medium size ASD (5-8 mm) may close spontaneously, but more than 15% stay open and require intervention for closure.

Option C is incorrect since medium size ASD may still close spontaneously as mentioned above.

Option D is incorrect since secundum ASD, particularly small and medium size are more likely to close than not.

Correct answer is B:

The newly heard murmur seems to suggest aortic regurgitation, a known complication to perimembrenous and outflow type VSD.  This occurs when tan aortic valve cusp becomes involved in the defect causing it to prolapse and eventually become incompetent resulting in regurgitation.  This is an indication to close the VSD surgically to reduce risk of further progression of the aortic valve disease.

Option A is incorrect since an increase in pulmonary blood flow due to a VSD will indeed cause a diastolic murmur across the VSD, however, this would be a mid-diastolic murmur at the apex and not an early diastolic murmur at the right upper sternal border.  Furthermore, the pulmonary vascular resistance drops in the first few weeks of life and is unlikely to continue to drop at age4-5 years.

Option C is incorrect since it likely that catheter closure at this point is likely to be contraindicated due to the likelihood of involvement of an aortic valve cusp in the VSD.  This will prevent proper deployment of the device and further damage to aortic valve.

Option D is incorrect since mitral stenosis produces a mid-diastolic murmur at the apex, not an early diastolic murmur at the right upper sternal border.

Correct answer is C:

It is always best to choose the least invasive therapy for any medical condition. �In considering the options available for closure of PDA, intravenous indomethacin is the least invasive, though not free of complications as it may cause gastric ulceration, thrmbocytopenia or precipitate renal impairment. �Indomethacin works best in premature infants, in the first few days of life. �Therefore the child in option (A) will be best treated with intravenous indomethacin.

Correct answer is B:

The ventricular septal defect in complete atrioventricular canal defect is typically large, therefore, the left to right shunting across it is laminar and not turbulent, thus does not cause an audible murmur. �On the other hand, atrioventricular valve regurgitation is turbulent and is the cause of murmur in most patients with this congenital heart disease.

Correct answer is A:

The systolic murmur is typical of aortic stenosis, occasionally the systolic murmur is preceded by an ejection click. Murmur is heard best over the right upper sternal border with radiation into the suprasternal notch, where a thrill is palpable. The diastolic murmur most probably reflects aortic regurgitation which may be associated with aortic stenosis due to deformed aortic valve cusps. The murmur of aortic regurgitation is early in diastole and decrescendo in nature.

Murmur of pulmonary stenosis is best heard over the left upper sternal border and those due to patent ductus arteriosus are best heard over the left sub-clavicular region.

Correct answer is B:

All grades of aortic stenosis require prophylaxis, unlike pulmonary valve disease where mild pulmonary stenosis does not require subacute bacterial endocarditis prophylaxis.

Conditions for which endocarditis prophylaxis is recommended

High-risk category
Prosthetic cardiac valves, including bioprosthetic and homograft valves
Previous bacterial endocarditis
Complex cyanotic congenital heart disease (e.g., single ventricle states, transposition of the great arteries, and tetralogy of Fallot)
Surgically constructed systemic-to-pulmonary shunts or conduits

Moderate-risk category
Most other congenital cardiac malformations, such as patent ductus arteriosus, ventricular septal defect, primum atrial septal defect, coarctation of the aorta, and bicuspid aortic valve
Acquired valvar dysfunction (e.g., rheumatic heart disease or collagen vascular disease)
Hypertrophic cardiomyopathy
Mitral valve prolapse with valvar regurgitation and/or thickened leaflets
Conditions for which endocarditis prophylaxis is not recommended

Negligible-risk category (no greater risk than that for the general population)
Isolated secundum atrial septal defect
Surgical repair of atrial septal defect, ventricular septal defect, or patent ductus arteriosus (without residua beyond 6�months)
Previous coronary artery bypass graft surgery
Mitral valve prolapse without valvar regurgitation
Physiologic, functional, or innocent heart murmurs
Previous Kawasaki disease without valvar dysfunction
Previous rheumatic fever without valvar dysfunction
Cardiac pacemakers (intravascular and epicardial) and implanted defibrillators

Correct answer is A:

In pulmonary stenosis there is systolic click caused by opening of the pulmonary valve. �This is followed by an ejection systolic murmur heard best over the left upper sternal border. �The second component of the second heart sound is caused by closure of the pulmonic valve. �Therefore in pulmonary stenosis, as blood will require more time to go through a stenotic valve, the closure of this valve will be delayed causing widening of splitting of second heart sound, until it completely disappears as the valve becomes too deformed to create a closure sound.

Correct answer is C:

The jet produced by forceful blood flow through a narrow pulmonary valve orifice results in dilation of the main pulmonary artery. In addition severe regurgitation of the pulmonary valve, as seen in patients with absent pulmonary valve, may cause dilation of the pulmonary artery.

Correct answer is C.

The values in set (A) suggest persistent fetal circulation (PFC). Dystolic BP in lower extremities is typically slightly higher in lower extremities than that of upper. The lower O2 saturation in the lower extremities suggest right to left shunting at the patent ductus arteriosus.

The values in set (B) are within normal limits.

The values in set (C) suggests severe coarctation of the aorta with low BP in lower extremities and lower saturation due to right to left shunting at the patent ductus arteriosus which is supplying blood flow to the descending aorta in view of coarctation proximal to the ductal insertion into the aorta. The coarctation will be more severe once the ductus arteriosus closes leading to poor cardiac output to the lower extremities, eventually leading to metabolic acidosis and cardiogenic shock.

The values in set (D) suggest cyanotic congenital heart disease with normal aortic arch.

Correct answer is C:

Post-coarcectomy hypertension is a known complication in patients after repair of coarctation of aorta; this is thought to be due to high rennin levels from pre-operative low renal perfusion and/or poor vascular development in post-coarctation region of the body due to low blood flow state for long time. The blood pressure in this patient is significantly elevated in both upper and lower extremities which rules out the possibility of re-coarctation.

Correct answer is B:

Patients with tetralogy of Fallot have decreased pulmonary blood flow due to pulmonary stenosis, which increases in intensity as the child grows. As the extent of pulmonary and right ventricular outflow tract stenosis increase the child becomes more prone to develop Hypercyanotic spells as well as increase incidence of right to left shunting of emboli or septic emboli from the systemic venous circulation to the systemic arterial circulation which may result in stroke or brain abscess. Congestive heart failure may develop if the right ventricle fails, however, this occurs in much older patients and is not associated with increase pulmonary blood flow, which as previously stated is reduced.

Correct answer is B:

This child appears to have a Hypercyanotic spell and is critically ill, therefore, starting an intravenous line may be difficult and require time. Morphine injection subcutaneously may break the cycle and therefore, should be immediately given. In the meantime an intravenous line could be initiated and esmolol or phenylephrine administered. Oxygen will not significantly benefit the child since cyanosis is due lack of pulmonary blood flow.

Correct answer is D:

Glen shunt provides pulmonary blood flow through the superior vena cava which typically is connected to the right pulmonary artery in an end-side fashion. The inferior vena cava continues to drain into the right atrium. The Fontan procedure eventually incorporates venous blood return from the inferior vena cava to the pulmonary circulation. A bi-directional shunt implies that the blood from the superior vena cava flows to both lungs.

Correct answer is B:

The high oxygen saturation noted in this child indicates significant increase in pulmonary blood flow. Acyanotic congenital heart disease, such as tricuspid atresia will present with increasing oxygen saturation as the pulmonary blood flow increases. High pulmonary blood flow results in improved oxygen saturation since there is larger fully saturated blood volume returning through the pulmonary veins to the heart, thus diluting the poorly saturated oxygen saturation returning from the body. However, this increase in pulmonary blood flow will also cause pulmonary edema and congestive heart failure manifested as tachypnea, tachycardia and failure to thrive. Systemic to pulmonary arterial shunts are fixed in diameter, as the child grows, the shunt size will be relatively smaller with less congestive heart failure. Anti-congestive heart failure medications, such as afterload reducing agents, diuretics and inotropic agents, such as digoxin can bridge the patient until the effective size of the shunt is smaller.

A Glen shunt will be performed eventually, but not at 3 months of age.

Providing oxygen supplementation will only reduce pulmonary vascular resistance more and result in further increase of pulmonary blood flow and congestive heart failure.

Correct answer is A:

Patients with transposition of the great vessels, especially those without a ventricular septal defect are extremely cyanotic at birth.

Correct answer is D:

In transposition of the great arteries, the pulmonary valve becomes posterior, which places it further away from the sternum and consequently the stethoscope. On the other hand the aortic valve is anterior and closer to the sternum. The loud nearby aortic valve and the soft further away pulmonary valve result in a single heart sound. On the other hand, it really is difficult to appreciate the splitting of second heart sound even in normal newborns in view of their rapid heart rate. Therefore, the issue of single heart sound in babies with transposition of the great arteries becomes a matter of roundmanship rather than any real benefit in clinical assessment.

Correce Answer: C

This child is likely to have DiGeorge syndrome which includes defects of the heart (outflow abnormalities), parathyroid gland and thymus gland. Failure of proper development of the thymus will cause T-cells immune deficiency. Not all patients with positive DiGeorge gene test are complete in their presentation, i.e. not all defect may be manifested.

Correct answer is C:

The snowman appearance refers to the 2 circular shadows, one on top of the other simulating figure 8 or a snowman. This is produced by the cardiac shadow making the lower round structure and the anomalous veins as the collect into a single vertical vein which ascends to meet a dilated innominant vein which runs horizontally to the right to meet the superior vena cava.

All other choices are associated with a narrow mediastinum due to abnormal antero-posterior relationship as in transposition of the great vessels and corrected transposition, or a single great vessel as in truncus arteriosus.

Correct answer is D:

Pulmonary veins drain into any of the systemic venous structures close to the heart such as superior and inferior vena cavae, right atrium and coronary sinus. These structures have lower pressures than that of the pulmonary veins, thus facilitating blood flow. On the other hand, the right ventricle has a higher pressure than the pulmonary veins which would prevent such a connection. Furthermore, the right ventricle is embryologically very distinct from the pulmonary veins, while the other structures listed above are in close proximity, which could lead to this embryological mal-development.